CN110567556B - Frequency modulation continuous wave radar level gauge for measuring material level in container - Google Patents
Frequency modulation continuous wave radar level gauge for measuring material level in container Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/284—Electromagnetic waves
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Abstract
The application relates to a frequency modulation continuous wave radar level gauge for measuring a material level in a container, and belongs to the technical field of radar level gauges. The application comprises the following steps: the local oscillation module is used for generating local oscillation signals; the transmitting path is used for receiving the local oscillation signal generated by the local oscillation module and forming electromagnetic waves so as to transmit the electromagnetic waves to the target object; the receiving path is used for receiving the electromagnetic wave reflected by the target object and forming a reflected signal; and the mixer is used for receiving the local oscillation signal generated by the local oscillation module and the reflected signal formed by the receiving path and mixing to form a mixed signal for determining the material level distance. The application is beneficial to solving the problem of the near-end measurement blind area of the frequency modulation continuous wave radar level meter, thereby improving the measurement reliability of the frequency modulation continuous wave radar level meter.
Description
Technical Field
The application belongs to the technical field of radar level gauges, and particularly relates to a frequency modulation continuous wave radar level gauge for measuring material level in a container.
Background
The frequency modulation continuous wave radar level gauge is one type of radar level gauge, as shown in fig. 1, and fig. 1 is a schematic diagram of a typical structure of a frequency modulation continuous wave radar level gauge in the related art.
In fig. 1, a processing module 1 is a device responsible for data processing, and the processing module 1 controls a local oscillation module 3 to output a local oscillation signal with a frequency changing through a frequency control module 2, where the frequency changing is generally linearly changed with time, that is, chirping. The local oscillation signal can be split into a feedback signal for frequency control by the frequency control module 2, and if the frequency control is open-loop control, the feedback signal can be omitted.
The local oscillation module 3 divides a local oscillation signal into one path to be used as a transmitting signal of the frequency modulation continuous wave radar level gauge for the circulator 4, and inputs the divided path into the mixer 5. In fig. 1, a microwave path 100 (hereinafter referred to as a transmit-receive common microwave path 100) is commonly used for signal transmission and reception of the fm continuous wave radar level gauge, and the rf connectors (100 a, 100 b), the rf cable 100c, the feed source 100d, the waveguide 100e and the antenna 100f in the transmit-receive common microwave path 100 are commonly used for transmission and reception, and isolation of signal transmission and reception is achieved by the circulator 4. As shown in fig. 2, fig. 2 is a schematic diagram of a typical structure of a circulator 4 in the related art, and when an input is at a port a, a port B is an output terminal, and a port C is an isolated terminal; and when input is at port B, port C is the output and port a is the isolated. For the frequency modulation continuous wave radar level gauge of the microwave path 100 which is shared by the current transmission and reception, the port A is connected to the local oscillation module 3, the port B is connected to the microwave path 100 which is shared by the transmission and reception, and the port C is connected to the mixer 5. The local oscillation module 3 transmits local oscillation signals to the mixer 5 through a port A of the mixer 5, transmits the local oscillation signals to the shared microwave channel 100 through a port B of the mixer 5, transmits electromagnetic waves to a target object through the shared microwave channel 100, receives the electromagnetic waves reflected by the target object through the shared microwave channel 100, forms reflected signals and transmits the reflected signals to the mixer 5. The mixer 5 mixes the local oscillation signal with the received reflected signal to obtain a mixed signal, and the mixed signal is the frequency difference signal between the local oscillation signal and the reflected signal. The mixer 5 transmits the mixed signal to the intermediate frequency amplifier 6 to amplify the signal, the intermediate frequency amplifier 6 outputs the amplified signal to the a/D conversion module 7, and the processing module 1 collects the mixed signal from the a/D conversion module 7 and processes the signal to obtain the level distance.
In practical use, for the fm continuous wave radar level gauge as shown in fig. 1, on the one hand, due to the deficiency in signal isolation of the circulator 4, it is shown that: the local oscillation signal of the local oscillation module 3 is input from a port A of the circulator 4 as a transmitting signal, most of the signal is output from a port B, and the least part of the signal is leaked from a port C and leaked into the mixer 5; on the other hand, when the transmission signal output from the port B is transmitted in the transmission/reception shared microwave path 100, the impedance matching of each connection point in the transmission/reception shared microwave path 100 cannot be perfect, for example, the connection structure of the radio frequency cable, the feed source, the waveguide, the antenna, etc. cannot be perfect, so that part of the transmission signal transmitted in the transmission/reception shared microwave path 100 is directly reflected back and enters the circulator 4 from the port B of the circulator 4.
The local oscillation signal leaked from the port C and the part of the transmission signal directly reflected in the microwave channel 100, which are shared by both transmission and reception, are used as reflection signals after entering the circulator 4, and then are sent to the mixer 5 for mixing, so that a stronger interference echo is formed at the near end of the fm continuous wave radar level gauge, and a measurement blind area is formed at the near end of the fm continuous wave radar level gauge. As shown in fig. 3 and fig. 4, fig. 3 is a schematic diagram of one measurement result of the fm continuous wave radar level gauge, fig. 4 is a schematic diagram of another measurement result of the fm continuous wave radar level gauge, and in fig. 3 and fig. 4, I is a near-end interference wave formed by a local oscillation signal that is leaked from the port C by a small portion of the isolation capability of the circulator 4 and a portion of the transmission signal that is reflected directly in the transmitting and receiving common microwave channel 100; and II is the reflected wave of the target object. Fig. 3 shows a situation that the object is far away from the fm continuous wave radar level gauge, in which near-end interference waves and object reflected waves are effectively distinguished, and when the object is near to the fm continuous wave radar level gauge, as shown in fig. 4, the interference of the near-end interference waves causes that the object reflected waves cannot be effectively identified, thereby forming a near-end measurement blind zone, and causing unreliable near-end measurement of the fm continuous wave radar level gauge.
Disclosure of Invention
In order to overcome the problems in the related art at least to a certain extent, the application provides the frequency modulation continuous wave radar level gauge for measuring the material level in the container, which is beneficial to solving the problem of a near-end measurement blind area of the frequency modulation continuous wave radar level gauge, and further improves the measurement reliability of the frequency modulation continuous wave radar level gauge.
In order to achieve the above purpose, the application adopts the following technical scheme:
the application provides a frequency modulation continuous wave radar level gauge for measuring a material level in a container, comprising:
the local oscillation module is used for generating local oscillation signals;
the transmitting path is used for receiving the local oscillation signal generated by the local oscillation module and forming electromagnetic waves so as to transmit the electromagnetic waves to a target object;
The receiving path is used for receiving the electromagnetic wave reflected by the target object and forming a reflected signal;
and the mixer is used for receiving the local oscillation signal generated by the local oscillation module and the reflection signal formed by the receiving path, and mixing the reflection signal to form a mixed signal for determining the material level distance.
Further, the method comprises the steps of,
The emission path is arranged in a vertical direction, has a certain space span in the electromagnetic wave emission direction from top to bottom, and comprises:
the transmitting feed source is used for receiving the local oscillation signal generated by the local oscillation module and converting the local oscillation signal into electromagnetic waves;
the transmitting antenna is used for transmitting electromagnetic waves generated by the transmitting feed source to the target object;
The transmitting antenna has a span in an electromagnetic wave transmitting direction;
The receiving path is arranged in a vertical direction, has a certain space span in the electromagnetic wave receiving direction from bottom to top, and comprises:
the receiving antenna is used for receiving electromagnetic waves reflected by the target object;
The receiving antenna has a span in an electromagnetic wave transmitting direction;
And the receiving feed source is used for converting the electromagnetic waves received by the receiving antenna into the reflected signals and transmitting the reflected signals to the mixer.
Further, the method comprises the steps of,
The transmit path further includes:
the transmitting waveguide is used for transmitting electromagnetic waves generated by the transmitting feed source to the transmitting antenna;
the receive path further includes:
And the receiving waveguide is used for transmitting the electromagnetic waves received by the receiving antenna to the receiving feed source.
Further, the method comprises the steps of,
The transmitting feed source is directly or indirectly connected with the local oscillation module, and the receiving feed source is directly or indirectly connected with the mixer.
Further, the method comprises the steps of,
The local oscillation module transmits signals with the transmitting feed source through a first radio frequency cable, and the mixer transmits signals with the receiving feed source through a second radio frequency cable;
The first radio frequency cable and the local oscillation module, the first radio frequency cable and the transmitting feed source, the second radio frequency cable and the mixer, and the second radio frequency cable and the receiving feed source are all connected through radio frequency connectors.
Further, the method comprises the steps of,
If the transmit path includes the transmit feed and the transmit antenna but does not include the transmit waveguide, and the receive path includes the receive feed and the receive antenna but does not include the receive waveguide, then the transmit feed, the receive feed are both formed on the same circuit board, and the transmit feed is located in the transmit antenna, and the receive feed is located in the receive antenna; or alternatively
If the transmit path includes the transmit feed, the transmit waveguide, and the transmit antenna, and the receive path includes the receive feed, the receive waveguide, and the receive antenna, then the transmit feed, the receive feed are formed on the circuit board with the transmit feed in the transmit waveguide, and the receive feed in the receive waveguide.
Further, the method comprises the steps of,
If the transmitting path includes the transmitting feed source and the transmitting antenna but does not include the transmitting waveguide, and the receiving path includes the receiving feed source and the receiving antenna but does not include the receiving waveguide, forming the transmitting feed source by using a portion of a first microstrip line formed on the circuit board extending into the transmitting antenna, wherein the first microstrip line is directly connected with the local oscillation module; and forming the receiving feed source by using a portion of a second microstrip line formed on the circuit board extending into the receiving antenna, wherein the second microstrip line is directly connected with the mixer; or alternatively
Forming the transmitting feed source by using a portion of the first microstrip line extending into the transmitting waveguide if the transmitting path includes the transmitting feed source, the transmitting waveguide, and the transmitting antenna, and the receiving path includes the receiving feed source, the receiving waveguide, and the receiving antenna; and forming the receiving feed source by utilizing the part of the second microstrip line extending into the receiving waveguide.
Further, the method comprises the steps of,
If the transmitting path comprises the transmitting feed source and the transmitting antenna but does not comprise the transmitting waveguide, and the receiving path comprises the receiving feed source and the receiving antenna but does not comprise the receiving waveguide, forming the transmitting feed source by using a first microstrip antenna formed on the circuit board, wherein the first microstrip antenna is positioned in the transmitting antenna and is directly connected with the local oscillator module; and forming the receiving feed source by using a second microstrip antenna formed on the circuit board, wherein the second microstrip antenna is positioned in the receiving antenna and is directly connected with the mixer; or alternatively
If the transmitting path comprises the transmitting feed source, the transmitting waveguide and the transmitting antenna, and the receiving path comprises the receiving feed source, the receiving waveguide and the receiving antenna, the transmitting feed source is formed by using the first microstrip antenna, wherein the first microstrip antenna is positioned in the transmitting waveguide and is directly connected with the local oscillator module; and forming the receiving feed source by using the second microstrip antenna, wherein the second microstrip antenna is positioned in the receiving waveguide, and the second microstrip line is directly connected with the mixer.
Further, the method comprises the steps of,
The transmitting antenna and the receiving antenna are of independent structures, and are arranged in parallel or close to each other.
Further, the method comprises the steps of,
The transmitting antenna and the receiving antenna are formed by separating an antenna baffle plate formed by a single antenna along the axial direction.
Further, the method comprises the steps of,
The transmitting waveguide and the receiving waveguide are of independent structures, and are arranged in parallel or close to each other.
Further, the method comprises the steps of,
The transmitting waveguide and the receiving waveguide are formed by separating waveguide partitions formed along the axial direction by single waveguides.
Further, the method comprises the steps of,
The frequency modulation continuous wave radar level gauge further comprises:
and a guard mechanism for preventing foreign objects from entering the transmitting path and the receiving path.
Further, the method comprises the steps of,
The protection mechanism comprises: and the antenna protective cover is formed at the free end antenna port of the transmitting antenna and the receiving antenna.
Further, the method comprises the steps of,
The protection mechanism comprises: and a blocking head formed in the transmitting waveguide and the receiving waveguide, respectively, or in the transmitting antenna or the receiving antenna, respectively.
Further, the method comprises the steps of,
The bottom of the antenna protective cover is of a plane structure, or of a convex structure or of a concave structure.
Further, the method comprises the steps of,
And if the transmitting antenna and the receiving antenna are respectively independent structures, the transmitting antenna and the receiving antenna are respectively close to one side of each other and are connected or close to the antenna protective cover.
Further, the method comprises the steps of,
If the transmitting antenna and the receiving antenna are formed by separating an antenna baffle formed by a single antenna along the axial direction, the antenna baffle is connected with or close to the antenna protection cover.
Further, the method comprises the steps of,
The transmitting antenna and the receiving antenna face the side face of the antenna protection cover respectively, and are attached to the antenna protection cover.
Further, the method comprises the steps of,
The transmitting antenna and the receiving antenna each face a side face of the antenna shield, and a fixing mechanism for fixing the fixed antenna shield is formed.
Further, the method comprises the steps of,
The antenna housing, the transmitting antenna and the receiving antenna form an inner space filled with an anti-deformation material capable of allowing microwaves to penetrate.
Further, the method comprises the steps of,
The transmitting antenna and the receiving antenna are horn antennas or lens antennas.
Further, the method comprises the steps of,
The frequency modulation continuous wave radar level gauge further comprises:
the frequency control module is connected with the local oscillation module;
The intermediate frequency amplifier is connected with the mixer;
the A/D conversion module is connected with the intermediate frequency module;
and the processing module is respectively connected with the A/D conversion module and the frequency control module.
Further, the method comprises the steps of,
The frequency modulation continuous wave radar level gauge further comprises:
and the display module is connected with the processing module.
Further, the method comprises the steps of,
The frequency modulation continuous wave radar level gauge further comprises:
the communication module is connected with the processing module; and/or the number of the groups of groups,
And the interface module is connected with the processing module.
Further, the method comprises the steps of,
The transmitting feed source and the receiving feed source are linear polarization feed sources.
Further, the method comprises the steps of,
The transmitting feed source and the receiving feed source are circularly polarized feed sources, and the polarization directions of the transmitting feed source and the receiving feed source are opposite, wherein one is in a left-hand polarization direction, and the other is in a right-hand polarization direction.
Further, the method comprises the steps of,
The transmitting waveguide and the receiving waveguide are cylindrical structures with semicircular cross sections, and plane side surfaces of the transmitting waveguide and the receiving waveguide are close to or close to each other so as to form a cylindrical outer contour.
Further, the method comprises the steps of,
The transmitting antenna and the receiving antenna are conical structures with semicircular cross sections, and plane side surfaces of the transmitting antenna and the receiving antenna are close to or close to each other so as to form a conical outer contour.
The application adopts the technical proposal and has at least the following beneficial effects:
according to the frequency modulation continuous wave radar level gauge, the ring device and the transmitting and receiving shared microwave channels are omitted, and the independent transmitting channels and receiving channels are arranged, so that the problem of a near-end measurement blind area of the frequency modulation continuous wave radar level gauge is solved, and the measurement reliability of the frequency modulation continuous wave radar level gauge is improved.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application as claimed.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a typical structure of a related art frequency modulated continuous wave radar level gauge;
FIG. 2 is a schematic diagram of a typical construction of a circulator of the related art;
FIG. 3 is a schematic diagram of a measurement of a frequency modulated continuous wave radar level gauge;
FIG. 4 is a schematic diagram of another measurement result of a frequency modulated continuous wave radar level gauge;
FIG. 5 is a schematic diagram of a frequency modulated continuous wave radar level gauge according to an embodiment of the present application;
FIG. 6 is a schematic diagram of a frequency modulated continuous wave radar level gauge according to another embodiment of the present application;
FIG. 7 is a schematic diagram of a frequency modulated continuous wave radar level gauge according to another embodiment of the present application;
FIG. 8 is a schematic diagram of a frequency modulated continuous wave radar level gauge according to another embodiment of the present application;
FIG. 9 is a schematic diagram showing the structure of FIG. 8A;
FIG. 10 is a schematic diagram of a frequency modulated continuous wave radar level gauge according to another embodiment of the present application;
fig. 11 is a schematic diagram showing a specific structure at B in fig. 10.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail below. It will be apparent that the described embodiments are only some, but not all, embodiments of the application. All other embodiments, based on the examples herein, which are within the scope of the application as defined by the claims, will be within the scope of the application as defined by the claims.
The present application provides a frequency modulation continuous wave radar level gauge for measuring a material level in a container, wherein the top of the container is provided with an opening or a window structure which can be penetrated by microwaves, and referring to fig. 5 to 7, the frequency modulation continuous wave radar level gauge comprises:
The local oscillation module 3 is used for generating local oscillation signals;
a transmitting path 200, configured to receive the local oscillation signal generated by the local oscillation module 3, and form an electromagnetic wave to transmit the electromagnetic wave to a target object;
A receiving path 300, configured to receive the electromagnetic wave reflected by the target object and form a reflected signal;
and the mixer 5 is used for receiving the local oscillation signal generated by the local oscillation module 3 and the reflected signal formed by the receiving path 300 and mixing to form a mixed signal for determining the level distance.
Specifically, in the foregoing embodiment, with respect to the fm continuous wave radar level gauge (such as the fm continuous wave radar level gauge shown in fig. 1) in the related art, the fm continuous wave radar level gauge (such as those shown in fig. 5 to 7) provided by the present application, by omitting the circulator 4 and the microwave channel 100 shared by transmitting and receiving, and adopting the separate transmitting channel 200 and receiving channel 300, on one hand, the problem that a part of the transmitting signal leaks due to insufficient isolation capability of the circulator, is treated as a reflected signal, and is then sent to the mixer for performing mixing processing can be solved; on the other hand, the independent transmitting path and receiving path realize the mutual independence of the signal transmission and the signal reception, and the transmitting path 200 is only used for transmitting functions and is not used for receiving; the receiving path 300 is used only for receiving and is not used for transmitting, so that the condition that a transmitting signal is directly coupled to the receiving path 300 does not exist, and even if each connection point in the transmitting path 200 can cause reflection of a signal, the signal reflected back in the transmitting path 200 cannot be received, so that the problem that part of the transmitting signal directly reflected back in the transmitting and receiving shared microwave path can be used as a reflecting signal after entering the circulator and then is transmitted to the mixer 5 for mixing processing can be solved. Therefore, the scheme of the embodiment of the application can effectively solve the problems in the two aspects, and further solve the problem of the near-end measurement blind area of the frequency modulation continuous wave radar level meter, thereby improving the measurement reliability of the frequency modulation continuous wave radar level meter.
In one embodiment, the transmit path 200 includes:
The emission path 200 is disposed in a vertical direction, and has a certain space span (as shown in fig. 8 and 10) in an electromagnetic wave emission direction from top to bottom, and includes: (as shown in FIG. 5)
A transmitting feed source 200a, configured to receive a local oscillation signal generated by the local oscillation module 3, and convert the local oscillation signal into electromagnetic waves;
a transmitting antenna 200b, configured to transmit electromagnetic waves generated by the transmitting feed source 200a to the target object;
The transmitting antenna 200b has a span in the electromagnetic wave transmitting direction;
The receiving path 300 is disposed in a vertical direction, and has a certain space span (as shown in fig. 8 and 10) in a bottom-up electromagnetic wave receiving direction, and includes: (as shown in FIG. 5)
A receiving antenna 300a for receiving electromagnetic waves reflected back by the target object;
the receiving antenna 300a has a span in the electromagnetic wave transmitting direction;
and a receiving feed 300b for converting the electromagnetic wave received by the receiving antenna 300a into the reflected signal and transmitting the reflected signal to the mixer.
Specifically, the transmitting feed 200a is connected to the local oscillation module 3, the receiving feed 300b is connected to the mixer 5, and it is seen that the mixer 5 is only connected to the receiving feed 300b, and is not connected to the transmitting feed 200a, so that the mixer 5 only receives the reflected signal formed by the receiving feed 300 b.
For transmitting antenna 200b and receiving antenna 300a, either a horn or a lens antenna may be used, and for horn antennas, the cross-section may be semi-circular, rectangular, or other shaped.
For both the transmit feed 200a and the receive feed 300b, the structures of both may be identical, and the particular feed structure may be a coaxial waveguide feed structure.
The transmitting feed source and the receiving feed source can be linear polarization feed sources, or the transmitting feed source and the receiving feed source are circular polarization feed sources, and the polarization directions of the transmitting feed source and the receiving feed source are opposite, wherein one is a left-hand polarization direction, and the other is a right-hand polarization direction. The feed source is positioned on the microwave circuit or fixed on the microwave circuit board, and the corresponding antenna is aligned to the feed source in the vertical direction below the feed source.
The transmitting antenna 200b and the receiving antenna 300a may be formed by metal casting, or may be formed by casting a plastic into a unitary structure and then coating the surface with a conductive material.
As shown in fig. 6, 8 and 10, the transmission path 200 further includes:
A transmitting waveguide 200c for transmitting the electromagnetic wave generated by the transmitting feed 200a to the transmitting antenna 200b;
The receive path 300 further includes:
And a receiving waveguide 300c for transmitting the electromagnetic wave received by the receiving antenna 300a to the receiving feed 300b.
Specifically, the transmitting antenna 200b transmits the radar wave generated by the transmitting feed 200a through the transmitting waveguide 200c, and transmits the radar wave received by the transmitting antenna 300a through the receiving waveguide 300c to the receiving feed 300b, and in practice, the axes of the transmitting waveguide 200c and the transmitting antenna 200b are collinear, and the axes of the receiving waveguide 300c and the receiving antenna 300a are collinear.
The transmitting waveguide 200c and the receiving waveguide 300c may be formed by metal casting, or may be formed by casting a plastic into a unitary structure and then coating the surface with a conductive material.
In one embodiment, the transmit feed 200a is directly or indirectly connected to the local oscillator module 3 and the receive feed 300b is directly or indirectly connected to the mixer 5.
For the case of indirect connection, as shown in fig. 7, in a specific embodiment, signals are transmitted between the local oscillation module 3 and the transmission feed 200a through a first radio frequency cable 200d, and signals are transmitted between the mixer 5 and the reception feed 300b through a second radio frequency cable 300 d;
The first rf cable 200d and the local oscillation module 3, the first rf cable 200d and the transmission feed source 200a, the second rf cable 300d and the mixer 5, and the second rf cable 300d and the reception feed source 300b are all connected by rf connectors (200 e, 200f, 300e, 300 f).
Specifically, as shown in fig. 7, the transmitting feed source 200a is indirectly connected with the local oscillation module 3 through a first radio frequency cable 200d, the receiving feed source 300b is indirectly connected with the mixer 5 through a second radio frequency cable 300d, and the transmitting feed source 200a and the receiving feed source 300b both transmit signals through radio frequency cables, so that the extension of the frequency modulation continuous wave radar level gauge in the length direction can be realized through the radio frequency cables.
In the case of direct connection, as shown in fig. 8 to 10, in practical application, the local oscillation module 3 and the mixer 5 are formed on one circuit board, the transmission feed 200a may be formed by a microstrip line directly connected to the local oscillation module 3, and the reception feed 300b may be formed by a microstrip line directly connected to the mixer 5. Alternatively, a microstrip antenna for transmitting may be formed on the circuit board and directly connected to the local oscillation module 3, and the microstrip antenna for transmitting forms the transmitting feed source 200a, and a microstrip antenna for receiving may be formed on the circuit board and directly connected to the mixer 5, and the microstrip antenna for receiving forms the receiving feed source 300b. For the microstrip antenna used as the feed source, the microstrip antenna can be a microstrip array antenna formed by a plurality of array elements or a microstrip antenna formed by a single array element. The direct connection between the transmit feed 200a and the local oscillator module 3 and the direct connection between the receive feed 300b and the mixer 5 helps to reduce impedance mismatch problems due to the connection point.
Further extended embodiments of the present application are described below, surrounding the direct connection of the transmitting feed 200a to the local oscillator module 3 and the direct connection of the receiving feed 300b to the mixer 5.
In one embodiment, if the transmit path 200 includes the transmit feed 200a and the transmit antenna 200b, but does not include the transmit waveguide 200c, and the receive path 300 includes the receive feed 300b and the receive antenna 300a, but does not include the receive waveguide 300c, then the transmit feed 200a, the receive feed 300b are all formed on the same circuit board 11, and the transmit feed 200a is located in the transmit antenna 200b, and the receive feed 300b is located in the receive antenna 300 a; or alternatively
As shown in fig. 8 to 10, if the transmission path 200 includes the transmission feed 200a, the transmission waveguide 200c, and the transmission antenna 200b, and the reception path 300 includes the reception feed 300b, the reception waveguide 300c, and the reception antenna 300a, the transmission feed 200a, the reception feed 300b are each formed on the circuit board 11 with the transmission feed 200a in the transmission waveguide 200c, and the reception feed 300b in the reception waveguide 300 c.
Specifically, for the case that the above-mentioned transmitting path 200 includes the transmitting feed 200a and the transmitting antenna 200b, but does not include the transmitting waveguide 200c, and the receiving path 300 includes the receiving feed 300b and the receiving antenna 300a, but does not include the receiving waveguide 300c, the radar wave generated by the transmitting feed 200a is directly transmitted through the transmitting antenna 200b, and the radar wave received by the receiving antenna 300a is directly transmitted to the receiving feed 300b, which needs to be satisfied in practical applications: the transmitting port of the transmitting feed 200a to the transmitting antenna 200b has a space span in the transmitting direction, and the receiving port of the receiving feed 300b to the patch antenna also needs to have a space span in the receiving direction, which can be achieved by the transmitting antenna 200b and the receiving antenna 300a themselves, for example, a horn antenna can be employed to achieve such space span.
Further, as shown in fig. 8 and 9, if the transmission path 200 includes the transmission feed 200a and the transmission antenna 200b but does not include the transmission waveguide 200c, and the reception path 300 includes the reception feed 300b and the reception antenna 300a but does not include the reception waveguide 300c, the transmission feed 200a is formed with a portion of a first microstrip line formed on the circuit board 11 extending into the transmission antenna 200b, wherein the first microstrip line is directly connected with the local oscillation module 3; and forming the reception feed 300b with a portion of a second microstrip line formed on the circuit board 11 extending into the reception antenna 300a, wherein the second microstrip line is directly connected to the mixer 5; or alternatively
If the transmission path 200 includes the transmission feed 200a, the transmission waveguide 200c, and the transmission antenna 200b, and the reception path 300 includes the reception feed 300b, the reception waveguide 300c, and the reception antenna 300a, the transmission feed 200a is formed using a portion of the first microstrip line extending into the transmission waveguide 200 c; and forming the reception feed 300b using a portion of the second microstrip line extending into the reception waveguide 300 c.
As shown in fig. 8 and 9, in particular, in the above-described related embodiments, the feed source is formed by a microstrip line, and in practical applications, the microstrip line extending into the waveguide may be made into a needle shape to serve as the feed source. The transmitting waveguide 200c and the receiving waveguide 300c are directly fixed on the circuit board 11, then openings are formed on the sides of the transmitting waveguide 200c and the receiving waveguide 300c, a part, which is connected with the local oscillation module 3 and extends into the transmitting waveguide 200c, forms a transmitting feed source 200a, and a transmitting signal generated by the local oscillation module 3 enters the transmitting waveguide 200c through the first microstrip line to enter and exit for transmission. The portion of the second microstrip line connected to the microwave reception signal input terminal of the mixer 5 extending into the reception waveguide 300c constitutes the reception feed 300b.
For the case where the transmitting path 200 does not include the transmitting waveguide 200c and the receiving path 300 does not include the receiving waveguide 300c, and the transmitting antenna 200b and the receiving antenna 300a are directly fixed to the circuit board 11, the transmitting antenna 200b and the receiving antenna 300a may employ horn antennas, and the related implementation may refer to the implementation where the sides of the transmitting waveguide 200c and the receiving waveguide 300c have openings, and microstrip lines are introduced.
Further, as shown in fig. 10 and 11, if the transmission path 200 includes the transmission feed 200a and the transmission antenna 200b but does not include the transmission waveguide 200c, and the reception path 300 includes the reception feed 300b and the reception antenna 300a but does not include the reception waveguide 300c, the transmission feed 200a is formed with a first microstrip antenna formed on the circuit board 11, wherein the first microstrip antenna is located in the transmission antenna 200b and is directly connected with the local oscillation module 3; and forming the receiving feed 300b using a second microstrip antenna formed on the circuit board 11, wherein the second microstrip antenna is located in the receiving antenna 300a and is directly connected to the mixer 5; or alternatively
If the transmission path 200 includes the transmission feed 200a, the transmission waveguide 200c and the transmission antenna 200b, and the reception path 300 includes the reception feed 300b, the reception waveguide 300c and the reception antenna 300a, the transmission feed 200a is formed using the first microstrip antenna, wherein the first microstrip antenna is located in the transmission waveguide 200c and is directly connected with the local oscillation module 3; and forming the receiving feed 300b by using the second microstrip antenna, wherein the second microstrip antenna is located in the receiving waveguide 300c, and the second microstrip line is directly connected with the mixer 5.
Specifically, fig. 10 shows a case where the transmitting path 200 includes the transmitting waveguide 200c and the receiving path 300 includes the receiving waveguide 300c in the above-described related embodiment, and the transmitting waveguide 200c and the receiving waveguide 300c are directly fixed to the circuit board 11. For the case where the transmission path 200 does not include the transmission waveguide 200c and the reception path 300 does not include the reception waveguide 300c, and the transmission antenna 200b and the reception antenna 300a are directly fixed to the circuit board 11, the transmission antenna 200b and the reception antenna 300a may employ horn antennas, and the related implementation may refer to the application in which microstrip antennas are provided in the transmission waveguide 200c and the reception waveguide 300c, respectively, as shown in fig. 10.
As shown in fig. 11, the microstrip antenna may be a microstrip array antenna formed of a plurality of array elements or a microstrip antenna formed of a single array element.
For the formation of the transmitting antenna 200b and the receiving antenna 300a, some related embodiments are described below.
In one embodiment, the transmitting antenna 200b and the receiving antenna 300a are independent structures, and the transmitting antenna 200b and the receiving antenna 300a are arranged in parallel or close to each other.
Specifically, the transmitting antenna 200b and the receiving antenna 300a are independent structures, and one may be an image of the other. In a specific application, a horn structure with a circular appearance can be formed by two horns with semicircular cross sections, for example, the transmitting antenna and the receiving antenna are conical structures with semicircular cross sections, and plane side surfaces of the transmitting antenna and the receiving antenna are close to or closely attached to each other to form a conical outer contour. The case shown in fig. 8 and 10 may be formed by attaching the transmitting antenna 200b and the receiving antenna 300a in parallel, and the attaching of the two may be realized by welding, bundling, bonding, fastening, mortise and tenon joint, or the like.
In another embodiment, the transmitting antenna 200b and the receiving antenna 300a are formed separately by an antenna spacer formed by a single antenna in the axial direction.
Specifically, the transmitting antenna 200b and the receiving antenna 300a are two modules of a single antenna, and are formed by separating antenna partitions, and in the case of a horn antenna, fig. 8 and 10 may also illustrate a case where a conductive partition is interposed between one horn antenna to separate the transmitting antenna 200b and the receiving antenna 300a.
For the formation of the transmitting waveguide 200c and the receiving waveguide 300c, some related embodiments are described below.
In one embodiment, the transmitting waveguide 200c and the receiving waveguide 300c are independent structures, and the transmitting waveguide 200c and the receiving waveguide 300c are disposed in parallel or close to each other.
Specifically, the transmitting waveguide 200c and the receiving waveguide 300c are independent structures, and one may be a mirror image of the other. In a specific application, two waveguides with semicircular or semi-elliptical cross sections can be combined into a waveguide with a circular or elliptical appearance, for example, the transmitting waveguide and the receiving waveguide are cylindrical structures with semicircular cross sections, and the planar sides of the transmitting waveguide and the receiving waveguide are close to or closely attached to each other to form a cylindrical outer contour. The case shown in fig. 8 and 10 may be formed by attaching the transmitting waveguide 200c and the receiving waveguide 300c in parallel, and the attaching of the two may be realized by welding, bundling, bonding, fastening, mortise and tenon joint, or the like.
In a particular application, where transmit antenna 200b and receive antenna 300a are joined to form a unitary antenna having a circular structure in cross-section, and where transmit waveguide 200c and receive waveguide 300c are joined to form a unitary waveguide also having a circular structure in cross-section, both the circular structure of unitary antenna and the circular structure of unitary waveguide may be collinear in axis.
The transmitting waveguide 200c and the receiving waveguide 300c may be waveguides having gradually increasing diameters.
In another embodiment, the transmitting waveguide 200c and the receiving waveguide 300c are formed separately by a waveguide partition formed by a single waveguide in the axial direction.
Specifically, the transmitting waveguide 200c and the receiving waveguide 300c are two modules of a single waveguide, and the case shown in fig. 8 and 10 may be that the transmitting waveguide 200c and the receiving waveguide 300c are formed by one single waveguide separated by a waveguide partition.
As shown in fig. 8 and 10, in one embodiment, the fm continuous wave radar level gauge further comprises:
A guard mechanism 12 for preventing foreign objects from entering the transmit path 200 and the receive path 300.
In the related art, the shielding mechanism 12 is capable of passing electromagnetic waves, but is capable of preventing foreign objects from entering, and in specific applications, the shielding mechanism 12 can function to block corrosion, steam, dust, or pressure and high temperature, etc., depending on the specific use of the fm continuous wave radar level gauge. The guard mechanism 12 of the present application also achieves the basic functions described above.
Further, the method comprises the steps of,
The guard mechanism 12 includes: an antenna shield (the shield mechanism 12 shown in fig. 8 and 10 is a shield) is formed at the free end antenna port of both the transmitting antenna 200b and the receiving antenna 300 a.
Specifically, fig. 8 and fig. 10 show a schematic structural diagram of an antenna protection cover, in a finished product of the fm continuous wave radar level gauge, the transmitting antenna 200b and the receiving antenna 300a are already installed, and an antenna port of the transmitting antenna 200b and the receiving antenna 300a for facing a target object is a free end antenna port.
Further, the method comprises the steps of,
The guard mechanism 12 includes: plugs are formed in the transmitting waveguide 200c and the receiving waveguide 300c, respectively, or in the transmitting antenna 200b or the receiving antenna 300a, respectively.
It should be noted that, in the related art, the antenna of the frequency modulation continuous wave radar level gauge is shared by receiving and transmitting, is a single antenna, is provided with an antenna housing or a plugging head to achieve the protection purpose, when the electromagnetic wave emitted by the frequency modulation continuous wave radar level gauge encounters the antenna housing or the plugging head, reflection will necessarily occur, a reflection signal is generated, the reflection signal will increase the interference wave at the near end of the frequency modulation continuous wave radar level gauge, and it can be understood that, when the frequency modulation continuous wave radar level gauge in the related art is provided with the antenna housing, the measurement blind area of the frequency modulation continuous wave radar level gauge will necessarily increase.
The application can effectively solve the problem of increasing the measurement blind area when the frequency modulation continuous wave radar level gauge is provided with the protection mechanism 12, and is specifically expressed as follows: in the present application, the transmitting antenna 200b and the receiving antenna 300a are arranged in parallel, the transmitting antenna 200b is only used for transmitting electromagnetic waves and the receiving antenna 300a is only used for receiving electromagnetic waves, in a specific application, the transmitting antenna 200b and the receiving antenna 300a are aligned to the target object, the transmitting antenna 200b transmits electromagnetic waves to the target object, when the electromagnetic waves in the transmitting direction meet the opposite part of the protection mechanism 12, a transmitting signal is generated, and because of separation and isolation between the transmitting antenna 200b and the receiving antenna 300a, the reflecting signal is reflected into the transmitting antenna 200b and is not received by the receiving antenna 300a, thus the problem of increasing measurement blind areas caused by the protection mechanism 12 can be solved.
In summary, by adopting the solution of the present application, compared to the fm continuous wave radar level gauge (such as the fm continuous wave radar level gauge shown in fig. 1) in the related art, the following three problems can be solved by omitting the circulator and simultaneously providing the independent transmitting channel 200 and the receiving channel 300:
First, can solve the problem that the insufficient isolation capability of the circulator causes a part of the emission signal to leak, is regarded as the reflection signal, and then is sent to the mixer 5 for mixing processing.
The second, independent transmitting path 200 and receiving path 300, realize the signal is independent each other, the transmitting path 200 only uses as the transmitting function, do not do and receive and use; the receiving path 300 is used only for receiving and is not used for transmitting, so that the condition that a transmitting signal is directly coupled to the receiving path 300 does not exist, and even if each connection point in the transmitting path 200 can cause reflection of a signal, the signal reflected back in the transmitting path 200 cannot be received, so that the problem that part of the transmitting signal directly reflected back in the transmitting and receiving shared microwave path can be used as a reflecting signal after entering the circulator and then is transmitted to the mixer 5 for mixing processing can be solved.
Third, the problem of increased measurement blind area caused by the guard mechanism 12 can be solved.
Therefore, the scheme of the embodiment of the application can effectively solve the problems of the three aspects, and further can solve the problem of a near-end measurement blind area of the frequency modulation continuous wave radar level meter, thereby improving the measurement reliability of the frequency modulation continuous wave radar level meter.
In one embodiment, the bottom of the antenna protection cover is of a plane structure, or of a convex structure or of a concave structure.
In practical use, the fm continuous wave radar level gauge is placed vertically, and the radome is also placed vertically, and the bottom of the radome is the portion facing the free end antenna ports of both the transmitting antenna 200b and the receiving antenna 300 a.
Specifically, the bottom of the antenna protection cover can be an upward concave conical surface or a spherical surface, and can also be a downward protruding conical surface or a spherical surface.
Regarding the relationship between the radome and the transmitting antenna 200b and the receiving antenna 300a, some related embodiments of the present application are described below.
In one embodiment, if the transmitting antenna 200b and the receiving antenna 300a are in independent structures, the transmitting antenna 200b and the receiving antenna 300a are respectively close to each other, and are connected or close to the antenna protection cover.
In another embodiment, if the transmitting antenna 200b and the receiving antenna 300a are formed separately by an antenna partition formed by a single antenna in the axial direction, the antenna partition is connected or close to the antenna shield.
Specifically, the connection mentioned in the two embodiments can be realized by means of bonding, threads, screws, buckles, clamping grooves, bundling and the like, and can play a supporting role on the antenna protection cover in the positive pressure occasion, and play a tightening role on the antenna protection cover in the negative pressure occasion to prevent the antenna protection cover from deforming.
In one embodiment, both the transmit antenna 200b and the receive antenna 300a each face a side of the antenna shield, conforming to the antenna shield.
Specifically, the side surface of the antenna protection cover is attached to the transmitting antenna 200b and the receiving antenna 300a, and in a high-voltage occasion, the transmitting antenna 200b and the receiving antenna 300a can play a supporting role on the antenna protection cover.
Further, both the transmitting antenna 200b and the receiving antenna 300a are each faced to a side surface of the antenna shield, and a fixing mechanism for fixing the fixed antenna shield is formed.
Specifically, the transmitting antenna 200b and the receiving antenna 300a fix the antenna protection cover through respective fixing mechanisms, so that the antenna protection cover can be effectively prevented from being deformed when being in a pressure field.
In one embodiment, the antenna housing and the internal space formed by the transmitting antenna and the receiving antenna are filled with a deformation-resistant material capable of allowing microwaves to penetrate.
Specifically, the deformation-resistant material can be plastic to fill the internal space formed by the antenna housing, the transmitting antenna and the receiving antenna, so that the antenna housing becomes solid, and the pressure resistance of the antenna housing is improved.
As shown in fig. 5 to 7, in one embodiment, the fm continuous wave radar level gauge further comprises:
the frequency control module 2 is connected with the local oscillation module 3;
An intermediate frequency amplifier 6 connected to the mixer 5;
The A/D conversion module 7 is connected with the intermediate frequency module;
the processing module 1 is respectively connected with the A/D conversion module 7 and the frequency control module 2.
Specifically, the processing module 1 may be a DSP processor, and the frequency control module 2 may be a phase-locked loop.
For the above-mentioned frequency control module 2, intermediate frequency amplifier 6, a/D conversion module 7 and processing module 1, the related applications may refer to the fm continuous wave radar level gauge in the related art, and in the background of the present application, the above-mentioned module components are also described correspondingly, so that reference may be made, and further description is omitted herein.
As shown in fig. 5 to 7, further, the fm continuous wave radar level gauge further includes:
And the display module 8 is connected with the processing module 1.
Specifically, the display module 8 may display data or curves or text, allowing the user to observe the current measurement results and to query and set parameters.
As shown in fig. 5 to 7, further, the fm continuous wave radar level gauge further includes:
a communication module 9 connected to the processing module 1; and/or the number of the groups of groups,
An interface module 10 is connected to the processing module 1.
Specifically, the external output signal mode may be 4-20mA, HART, FF, profibus modes through the communication module and/or the interface module.
It is to be understood that the same or similar parts in the above embodiments may be referred to each other, and that in some embodiments, the same or similar parts in other embodiments may be referred to.
It should be noted that in the description of the present application, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Furthermore, in the description of the present application, unless otherwise indicated, the meaning of "plurality", "multiple" means at least two.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected through intervening elements. Further, "connected" as used herein may include wireless connections. The use of the term "and/or" includes any and all combinations of one or more of the associated listed items.
Any process or method description in a flowchart or otherwise described herein may be understood as: means, segments, or portions of code representing executable instructions including one or more steps for implementing specific logical functions or processes are included in the preferred embodiment of the present application in which functions may be executed out of order from that shown or discussed, including in a substantially simultaneous manner or in an inverse order, depending upon the function involved, as would be understood by those skilled in the art of embodiments of the present application.
It is to be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.
Those of ordinary skill in the art will appreciate that all or a portion of the steps carried out in the method of the above-described embodiments may be implemented by a program to instruct related hardware, where the program may be stored in a computer readable storage medium, and where the program, when executed, includes one or a combination of the steps of the method embodiments.
Furthermore, the functional units in the various embodiments of the present application may be integrated into one processing module 58, or the units may exist physically separately, or two or more units may be integrated into one module. The integrated modules may be implemented in hardware or in software functional modules. The integrated modules may also be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product.
The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, or the like.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the application, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the application.
Claims (23)
1. A frequency modulated continuous wave radar level gauge for measuring a level of a material in a container, comprising:
the local oscillation module is used for generating local oscillation signals;
the transmitting path is used for receiving the local oscillation signal generated by the local oscillation module and forming electromagnetic waves so as to transmit the electromagnetic waves to a target object;
The receiving path is used for receiving the electromagnetic wave reflected by the target object and forming a reflected signal;
the mixer is used for receiving the local oscillation signal generated by the local oscillation module and the reflected signal formed by the receiving channel, and mixing the reflected signal to form a mixed signal for determining the material level distance;
a guard mechanism for preventing foreign objects from entering the transmit path and the receive path;
The emission path is arranged in a vertical direction, has a certain space span in the electromagnetic wave emission direction from top to bottom, and comprises: the transmitting feed source is used for receiving the local oscillation signal generated by the local oscillation module and converting the local oscillation signal into electromagnetic waves; the transmitting antenna is used for transmitting electromagnetic waves generated by the transmitting feed source to the target object; the transmitting antenna has a span in an electromagnetic wave transmitting direction; the receiving path is arranged in a vertical direction, has a certain space span in the electromagnetic wave receiving direction from bottom to top, and comprises: the receiving antenna is used for receiving electromagnetic waves reflected by the target object; the receiving antenna has a span in an electromagnetic wave transmitting direction; the receiving feed source is used for converting electromagnetic waves received by the receiving antenna into the reflected signals and transmitting the reflected signals to the mixer; or the transmitting path comprises the transmitting feed source, the transmitting antenna and a transmitting waveguide, and the transmitting waveguide is used for transmitting electromagnetic waves generated by the transmitting feed source to the transmitting antenna; the receiving path comprises the receiving feed source, the receiving antenna and: the receiving waveguide is used for transmitting electromagnetic waves received by the receiving antenna to the receiving feed source;
The transmitting feed source is directly or indirectly connected with the local oscillation module, and the receiving feed source is directly or indirectly connected with the mixer;
And if the transmit path includes the transmit feed and the transmit antenna, but does not include the transmit waveguide, and the receive path includes the receive feed and the receive antenna, but does not include the receive waveguide, then the transmit feed, the receive feed are both formed on the same circuit board, and the transmit feed is located in the transmit antenna, and the receive feed is located in the receive antenna; the transmitting feed source is formed by utilizing the part of the first microstrip antenna formed on the circuit board extending into the transmitting antenna, wherein the first microstrip antenna is directly connected with the first microwave pulse source; and forming the receiving feed source by using a portion of a second microstrip antenna formed on the circuit board extending into the receiving antenna, wherein the second microstrip antenna is directly connected with the mixer;
Or if the transmit path includes the transmit feed, the transmit waveguide, and the transmit antenna, and the receive path includes the receive feed, the receive waveguide, and the receive antenna, the transmit feed, the receive feed are formed on the circuit board with the transmit feed in the transmit waveguide, and the receive feed in the receive waveguide; the part of the first microstrip antenna extending into the transmitting waveguide is utilized to form the transmitting feed source; and forming the receiving feed source by utilizing the part of the second microstrip antenna extending into the receiving waveguide.
2. The frequency modulated continuous wave radar level gauge according to claim 1, wherein,
The local oscillation module transmits signals with the transmitting feed source through a first radio frequency cable, and the mixer transmits signals with the receiving feed source through a second radio frequency cable;
The first radio frequency cable and the local oscillation module, the first radio frequency cable and the transmitting feed source, the second radio frequency cable and the mixer, and the second radio frequency cable and the receiving feed source are all connected through radio frequency connectors.
3. The frequency modulated continuous wave radar level gauge according to claim 1, wherein,
If the transmitting path comprises the transmitting feed source and the transmitting antenna but does not comprise the transmitting waveguide, and the receiving path comprises the receiving feed source and the receiving antenna but does not comprise the receiving waveguide, forming the transmitting feed source by using a first microstrip antenna formed on the circuit board, wherein the first microstrip antenna is positioned in the transmitting antenna and is directly connected with the local oscillator module; and forming the receiving feed source by using a second microstrip antenna formed on the circuit board, wherein the second microstrip antenna is positioned in the receiving antenna and is directly connected with the mixer; or alternatively
If the transmitting path comprises the transmitting feed source, the transmitting waveguide and the transmitting antenna, and the receiving path comprises the receiving feed source, the receiving waveguide and the receiving antenna, the transmitting feed source is formed by using the first microstrip antenna, wherein the first microstrip antenna is positioned in the transmitting waveguide and is directly connected with the local oscillator module; and forming the receiving feed source by using the second microstrip antenna, wherein the second microstrip antenna is positioned in the receiving waveguide and is directly connected with the mixer.
4. A fm continuous wave radar level gauge according to claim 1, wherein said transmitting antenna and said receiving antenna are of independent construction, and said transmitting antenna and said receiving antenna are arranged in parallel or in close proximity to each other.
5. The fm continuous wave radar level gauge according to claim 1, wherein said transmitting antenna and said receiving antenna are formed separately by an antenna spacer formed by a single antenna in an axial direction.
6. The fm continuous wave radar level gauge according to claim 1, wherein said transmitting waveguide and said receiving waveguide are of independent structures, and said transmitting waveguide and said receiving waveguide are disposed in parallel or in close proximity to each other.
7. The fm continuous wave radar level gauge according to claim 1, wherein said transmitting waveguide and said receiving waveguide are formed separately by a waveguide partition formed by a single waveguide in an axial direction.
8. The frequency modulated continuous wave radar level gauge according to claim 1, wherein,
The protection mechanism comprises: and the antenna protective cover is formed at the free end antenna port of the transmitting antenna and the receiving antenna.
9. The frequency modulated continuous wave radar level gauge according to claim 1, wherein,
The protection mechanism comprises: and a blocking head formed in the transmitting waveguide and the receiving waveguide, respectively, or in the transmitting antenna or the receiving antenna, respectively.
10. The fm continuous wave radar level gauge according to claim 8, wherein said antenna shield has a bottom portion that is planar, or convex, or concave.
11. The frequency modulated continuous wave radar level gauge according to claim 8, wherein,
And if the transmitting antenna and the receiving antenna are respectively independent structures, the transmitting antenna and the receiving antenna are respectively close to one side of each other and are connected or close to the antenna protective cover.
12. The frequency modulated continuous wave radar level gauge according to claim 8, wherein,
If the transmitting antenna and the receiving antenna are formed by separating an antenna baffle formed by a single antenna along the axial direction, the antenna baffle is connected with or close to the antenna protection cover.
13. A fm continuous wave radar level gauge according to claim 8, wherein said transmitting antenna and said receiving antenna each face a side of said antenna shield, and are attached to said antenna shield.
14. A fm continuous wave radar level gauge according to claim 8, wherein said transmitting antenna and said receiving antenna are each facing a side of said antenna shield, a fixing mechanism being formed for fixing said antenna shield.
15. The fm continuous wave radar level gauge according to claim 8, wherein an interior space formed by said antenna shield and said transmitting and receiving antennas is filled with a deformation resistant material that is transparent to microwaves.
16. A fm continuous wave radar level gauge according to claim 1, wherein said transmitting antenna and said receiving antenna are both horn antennas or lens antennas.
17. The fm continuous wave radar level gauge according to claim 1, wherein said fm continuous wave radar level gauge further comprises:
the frequency control module is connected with the local oscillation module;
The intermediate frequency amplifier is connected with the mixer;
the A/D conversion module is connected with the intermediate frequency amplifier;
and the processing module is respectively connected with the A/D conversion module and the frequency control module.
18. The fm continuous wave radar level gauge according to claim 17, wherein said fm continuous wave radar level gauge further comprises:
and the display module is connected with the processing module.
19. The fm continuous wave radar level gauge according to claim 17, wherein said fm continuous wave radar level gauge further comprises:
the communication module is connected with the processing module; and/or the number of the groups of groups,
And the interface module is connected with the processing module.
20. The frequency modulated continuous wave radar level gauge according to claim 1, wherein said transmitting feed and said receiving feed are linearly polarized feeds.
21. The fm continuous wave radar level gauge according to claim 1, wherein said transmitting feed and said receiving feed are circularly polarized feeds and have opposite polarization directions, wherein one is left-hand polarization and the other is right-hand polarization.
22. The fm continuous wave radar level gauge according to claim 6, wherein said transmitting waveguide and said receiving waveguide are cylindrical structures having semicircular cross sections, and planar sides of said transmitting waveguide and said receiving waveguide are adjacent or abutted to each other to form a cylindrical outer profile.
23. A fm continuous wave radar level gauge according to claim 4, wherein said transmitting antenna and said receiving antenna are tapered structures having semi-circular cross sections, and planar sides of said transmitting antenna and said receiving antenna are adjacent or abutted against each other to form a conical outer profile.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911041080.4A CN110567556B (en) | 2019-10-30 | 2019-10-30 | Frequency modulation continuous wave radar level gauge for measuring material level in container |
| PCT/CN2019/115539 WO2021082030A1 (en) | 2019-10-30 | 2019-11-05 | Frequency-modulated continuous-wave radar level meter for measuring material level in container |
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| CN201911041080.4A CN110567556B (en) | 2019-10-30 | 2019-10-30 | Frequency modulation continuous wave radar level gauge for measuring material level in container |
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| CN111834743B (en) * | 2020-06-19 | 2021-04-06 | 北京微度芯智科技有限责任公司 | Level meter antenna radio frequency board, antenna structure and antenna system |
| CN113375758A (en) * | 2021-07-08 | 2021-09-10 | 北京锐达仪表有限公司 | Radar level meter with variable beam angle |
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| CN103176181A (en) * | 2011-12-20 | 2013-06-26 | 中国电子科技集团公司第五十研究所 | Nonlinear node detector of frequency modulation continuous wave system |
| CN107144822A (en) * | 2017-06-29 | 2017-09-08 | 成都瑞达物联科技有限公司 | Millimetre-wave radar integrated radio-frequency front end |
| CN210664667U (en) * | 2019-10-30 | 2020-06-02 | 北京锐达仪表有限公司 | Frequency modulation continuous wave radar level meter for measuring material level in container |
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