CN111914976B

CN111914976B - Novel combined type UWB electronic tags

Info

Publication number: CN111914976B
Application number: CN202010745107.4A
Authority: CN
Inventors: 涂振益; 王博; 张亮; 张伟贤
Original assignee: Fu Zhou Internet Of Things Open Lab
Current assignee: Fu Zhou Internet Of Things Open Lab
Priority date: 2020-07-29
Filing date: 2020-07-29
Publication date: 2022-03-25
Anticipated expiration: 2040-07-29
Also published as: CN111914976A

Abstract

The invention relates to the technical field of electronics, in particular to a novel composite UWB electronic tag. The novel combined type UWB electronic tag comprises: the system comprises an ultra-wideband antenna, a first duplexer, a second duplexer, a power amplifier, a low-noise amplifier, an attenuator and an MCU chip; one end of the power amplifier is connected with the first duplexer, and the other end of the power amplifier is connected with the second duplexer; one end of the low-noise amplifier is connected with the attenuator, and the other end of the low-noise amplifier is connected with the first duplexer; the attenuator is connected with the second duplexer; the MCU chip is connected with the first duplexer and the second duplexer. The electronic tag receiving signal and the transmitting signal are switched through the first duplexer and the second duplexer, wherein a power amplifier is arranged on a transmitting path, so that the power of the transmitting signal is increased, and the interference carrying capacity is improved. And a low noise amplifier is arranged on the receiving path, so that the receiving noise coefficient can be reduced and the receiving sensitivity can be improved.

Description

Novel combined type UWB electronic tags

Technical Field

The invention relates to the technical field of electronics, in particular to a novel composite UWB electronic tag.

Background

Ultra wide band (UWB for short) is a carrier-free communication technology, which uses nanosecond to microsecond non-sine wave narrow pulse to transmit data, and uses subnanosecond Ultra-narrow pulse to perform close-range accurate indoor positioning, the accuracy can reach about 10 cm, and the Ultra wide band has the advantages of low power consumption, strong anti-interference capability, strong anti-multipath effect capability and the like.

Although the UWB technology has obvious advantages in short-distance high-speed data transmission applications, the transmitted power intensity of the UWB technology is limited, and the UWB technology cannot well resist burst interference and effectively communicate over long distances, regardless of single-pulse signals or multi-pulse signals. Therefore, in some special applications such as military and mine communication, communication is limited under the severe electromagnetic environment.

In addition, the existing tag antenna has a large size, is not easy to integrate and miniaturize, has a narrow impedance band, does not have band-stop or filtering characteristics, and has poor anti-interference performance. All these disadvantages make the existing UWB electronic tag limited in function and application.

Disclosure of Invention

Therefore, a novel composite UWB electronic tag is needed to be provided to solve the problems of large size, poor anti-interference performance and the like of the antenna of the existing electronic tag. The specific technical scheme is as follows:

a novel composite UWB electronic tag comprising: the system comprises an ultra-wideband antenna, a first duplexer, a second duplexer, a power amplifier, a low-noise amplifier, an attenuator and an MCU chip;

one end of the power amplifier is connected with the first duplexer, and the other end of the power amplifier is connected with the second duplexer;

one end of the low-noise amplifier is connected with the attenuator, and the other end of the low-noise amplifier is connected with the first duplexer;

the attenuator is connected with the second duplexer;

the first duplexer is connected with the ultra-wideband antenna;

the MCU chip is connected with the first duplexer and the second duplexer;

the antenna includes: the device comprises a substrate, a vibrator, a microstrip feeder line and a ground patch;

the oscillator is oval, the oscillator and the microstrip feeder line are both arranged on the front surface of the substrate, and the oscillator is connected with the microstrip feeder line to form a current path;

the grounding patch is arranged on the back surface of the substrate and is in a semi-elliptical shape;

the oscillator is provided with a gap in an Contraband shape with an opening pointing to the microstrip feeder line, the gap is positioned in the middle of the oscillator, and the total length of the gap is one half of the wavelength corresponding to the notch central frequency.

Further, the method also comprises the following steps: the system comprises a balun, a UWB chip, a Bluetooth chip, a ceramic antenna and a sensor module;

one end of the balun is connected with the second duplexer, and the other end of the balun is connected with the UWB;

the first end of the Bluetooth is connected with the UWB, the second end of the Bluetooth is connected with the ceramic antenna, and the third end of the Bluetooth is connected with the sensor module;

the sensor module comprises one or more of the following: six-axis acceleration sensor, baroceptor.

Furthermore, pi-type impedance matching is arranged between the ultra-wideband antenna and the first duplexer connecting line.

Further, the power amplifier is of a GRF2101 model.

Further, the low noise amplifier is BGB707L7 ESD.

Further, the attenuator includes three resistors, and the three resistors constitute the RF attenuator in pi type.

Further, the substrate is a substrate FR-4; the thickness of the substrate is 2 mm.

Further, the microstrip feeder line is a 50 ohm microstrip line.

Further, the distance between the grounding patch and the vibrator is 0.1 mm.

The invention has the beneficial effects that: in the invention, the electronic tag receiving signal and the transmitting signal are switched by the first duplexer and the second duplexer, wherein the power amplifier is arranged on the transmitting path, so that the power of the transmitting signal is increased, and the interference carrying capacity is improved. The low noise amplifier is arranged on the receiving path, so that the receiving noise coefficient can be reduced and the receiving sensitivity can be improved, and the attenuator is connected to one end of the low noise amplifier, so that the supersaturation of the receiving signal can be avoided.

In addition, an oscillator in the ultra-wideband antenna is in an oval shape, a slot is formed in the oscillator, the slot is in an Contraband shape with an opening pointing to a microstrip feeder line, the slot is located in the middle of the oscillator, and the total length of the slot is one half of the wavelength corresponding to the notch center frequency. In the ultra-wideband antenna printing elliptical antenna, a part of the element is properly deducted according to the current fringing characteristic of the antenna, and the impedance influence on the ultra-wideband antenna can be controlled within an acceptable range. The oscillator is provided with a slot with the total length corresponding to 1/2 wavelengths corresponding to the notch central frequency, so that the current under the corresponding notch frequency is concentrated at two ports of the slot, the currents at the two ports are opposite, the magnetic fields generated at the two ports are mutually offset, the original radiation characteristic of the ultra-wideband antenna is damaged, and the radiation of the antenna in the frequency band is inhibited. Therefore, the method for slotting the slots on the elliptical oscillator body can enable the ultra-wideband antenna to realize a wave trapping function on a frequency band with interference in ultra-wideband communication.

And pi-type impedance matching is arranged between the ultra-wideband antenna and the first duplexer connecting circuit so as to improve standing waves.

One end of the balun is connected with the second duplexer, and the other end of the balun is connected with the UWB; the first end of the Bluetooth is connected with the UWB, the second end of the Bluetooth is connected with the ceramic antenna, and the third end of the Bluetooth is connected with the sensor module; the sensor module comprises one or more of the following: six-axis acceleration sensor, baroceptor. The wireless communication of small data volume data transmission can be realized by adopting Bluetooth communication, and the Bluetooth communication and the UWB communication are complementary. And the six-axis acceleration sensor can be used for monitoring the motion state of an object, and the air pressure sensor can measure the relative height according to the change of air pressure at different heights.

The substrate is a substrate FR-4, the dielectric constant of the substrate is 4.4, the thickness of the substrate is 2mm, and the size of the vibrator is favorably reduced. Making the antenna smaller.

The ground patch is in a semi-elliptical shape, and has more uniform radiation characteristics and better matching characteristics. The vibrator is oval, and the smooth gradual change structure of the vibrator is beneficial to energy radiation and reduces reflection.

Drawings

Fig. 1 is a first schematic connection diagram of a novel hybrid UWB electronic tag module according to an embodiment;

FIG. 2 is a circuit diagram of a novel hybrid UWB electronic tag according to an embodiment;

FIG. 3 is a schematic circuit diagram of the MCU chip according to the embodiment;

fig. 4 is a second connection diagram of a novel hybrid UWB electronic tag module according to an embodiment;

FIG. 5 is a schematic diagram of a six-axis accelerometer and barometric pressure sensor circuit according to an embodiment;

FIG. 6 is a schematic diagram of an antenna according to an embodiment;

FIG. 7 is a schematic diagram of the structure and dimensions of an antenna according to an embodiment;

FIG. 8 is a schematic illustration of the notching effect described in the embodiments.

Description of reference numerals:

100. a novel composite UWB electronic tag is provided,

101. an ultra-wideband antenna is provided,

102. a first duplexer, a first optical fiber and a second optical fiber,

103. the second duplexer is used for transmitting the signal to the second duplexer,

104. a power amplifier for the power source and a power amplifier for the power source,

105. a low noise amplifier for amplifying the low noise signal,

106. an attenuator, which is provided with a plurality of attenuators,

107. an MCU chip is arranged on the base plate,

108. the number of the balun is equal to the number of the balun,

109. a UWB chip having a plurality of UWB chips,

110. a Bluetooth chip, a Bluetooth chip and a Bluetooth module,

111. a ceramic antenna, which is used for the antenna,

112. the sensor module is provided with a sensor module,

1. a substrate, a first electrode and a second electrode,

2. a vibrator which is provided with a vibrator and a vibration generator,

3. a microstrip feed line,

4. a ground patch is provided on the substrate,

5. a gap.

Detailed Description

To explain technical contents, structural features, and objects and effects of the technical solutions in detail, the following detailed description is given with reference to the accompanying drawings in conjunction with the embodiments.

Referring to fig. 1 to 8, in the present embodiment, a novel composite UWB electronic tag 100 is mainly applied to UWB indoor ranging. The specific implementation mode is as follows:

a novel hybrid UWB electronic tag 100 comprising: an ultra-wideband antenna 101, a first duplexer 102, a second duplexer 103, a power amplifier 104, a low noise amplifier 105, an attenuator 106, and an MCU chip 107;

one end of the power amplifier 104 is connected to the first duplexer 102, and the other end of the power amplifier 104 is connected to the second duplexer 103;

one end of the low noise amplifier 105 is connected with an attenuator 106, and the other end of the low noise amplifier 105 is connected with the first duplexer 102;

the attenuator 106 is connected to the second duplexer 103;

the first duplexer 102 is connected with the ultra-wideband antenna 101;

the MCU chip 107 is connected with the first duplexer 102, and the MCU chip 107 is connected with the second duplexer 103;

the antenna 101 includes: the device comprises a substrate 1, a vibrator 2, a microstrip feeder line 3 and a grounding patch 4;

the oscillator 2 is oval, the oscillator 2 and the microstrip feeder line 3 are both arranged on the front surface of the antenna 101, and the oscillator 2 is connected with the microstrip feeder line 3 to form a current path;

the grounding patch 4 is arranged on the back surface of the substrate 11, and the grounding patch 4 is in a semi-elliptical shape;

the oscillator 2 is provided with a slot 5, the slot 5 is in an Contraband shape with an opening pointing to the microstrip feeder 3, the slot 5 is located in the middle of the oscillator 2, and the total length of the slot 5 is one half of the wavelength corresponding to the notch central frequency.

In this embodiment, model DW1000 was used as the UWB chip, and the output power spectral density was-41.3 dBm/MHz. The switch between the transmitting and receiving paths is realized by controlling the on-off of the first duplexer 102 and the second duplexer 103 through the I/O port of the MCU chip 107, and the specific circuit diagram of the switch and the circuit diagram of the novel composite UWB electronic tag 100 are shown in fig. 2. In this embodiment, the MCU chip 107 has a model nRF52832, and a specific circuit diagram is shown in fig. 3.

The following describes two cases of the line transmitting signal and receiving signal respectively:

transmitting a signal: the first duplexer 102 and the second duplexer 103 are controlled by the MCU chip 107 to switch the circuits to transmit signals, and the transmit signals of the DW1000 are transmitted through the ultra-wideband antenna 101 after passing through the power amplifier 104. In this embodiment, the power amplifier 104 with 18dB gain is added to the transmit path to boost the transmit signal power of DW1000 from the previous-41.3 dBm/MHz to-23.3 dBm/MHz. The PA adopts GRF2101 of GRF, the working frequency band is 4.0to 10.0GHz, the noise coefficient is 0.90dB, the gain is 18.0dB, and the compression point of 1dB is 10.0 dBm. By adding the power amplifier 104 to the transmission path, the ranging range of the entire system can be increased. When there is an object block between the nodes, the signal of the direct path will be attenuated when passing through the object, if the signal is attenuated to be below the receiving threshold of the receiving node, the direct path can not be detected, but the reflected path with a longer distance is detected, thereby causing the ranging error. Therefore, the more important thing for improving the transmitting power of the signal is that when the communication direct path is blocked, the radio frequency signal can store higher transmission power after passing through the blocked object, so that the radio frequency signal can be detected by the receiving node more easily, and the ranging precision between the nodes is ensured.

Receiving a signal

By controlling the first duplexer 102 and the second duplexer 103 to switch the circuits to receive signals through the MCU chip 107, adding an appropriate low noise amplifier 105 to the receive path can improve the receive sensitivity. The low noise amplifier 105 can reduce the reception noise figure to improve the reception sensitivity of the DW 1000. The low noise amplifier 105 effectively improves the 3-4 dB receiving sensitivity by adopting BGB707L7 ESD.

In addition, an attenuator 106 is added after the low noise amplifier 105 to prevent the second duplexer 103 from over-saturating the received signal. The attenuator 106 may constitute the RF attenuator 106 in pi type by using 3 resistors.

In this embodiment, further, a broadband matching (dual L-shaped) circuit is provided on the feeder between the first duplexer 102 and the ultra-wideband antenna 101 to improve the standing wave reception, and one L-shaped circuit performs matching at the high frequency end of the antenna 101 and the other L-shaped circuit performs matching at the low frequency end, so that the standing wave ratio over the entire wideband is closer to 1.

Further, as shown in fig. 4, the present embodiment further includes: the system comprises a balun 108, a UWB chip 109, a Bluetooth chip 110, a ceramic antenna 111 and a sensor module 112;

one end of the balun 108 is connected to the second duplexer 103, and the other end of the balun 108 is connected to the UWB chip 109;

a first end of the bluetooth chip 110 is connected with the UWB chip 109, a second end of the bluetooth chip 110 is connected with the ceramic antenna 111, and a third end of the bluetooth chip 110 is connected with the sensor module 112;

the sensor module 112 includes one or more of the following: six-axis acceleration sensor, baroceptor.

The six-axis acceleration sensor and the air pressure sensor are shown in fig. 5.

By adopting the balun 108, impedance conversion can be realized, and common-mode interference is effectively inhibited. The wireless communication of small data volume data transmission can be realized by adopting the Bluetooth chip 110 for communication, and the communication with the UWB chip 109 is complementary. And the sensor module 112 integrates a six-axis acceleration sensor and a pneumatic pressure sensor. The six-axis acceleration sensor is used for monitoring the motion state of an object, and the air pressure sensor can measure the relative height according to the change of air pressure at different heights. So that the novel hybrid UWB electronic tag 100 can be applied to more scenes.

As shown in fig. 6, the antenna 101 includes: the device comprises a substrate 1, a vibrator 2, a microstrip feeder line 3 and a grounding patch 4; the vibrator 2 is oval, the vibrator 2 and the microstrip feeder line 3 are both arranged on the front surface of the substrate 1, and the vibrator 2 is connected with the microstrip feeder line 3 to form a current path; the grounding patch 4 is arranged on the back surface of the substrate 1, and the grounding patch 4 is in a semi-elliptical shape; the oscillator 2 is provided with a slot 5, the slot 5 is in an Contraband shape with an opening pointing to the microstrip feeder 3, the slot 5 is located in the middle of the oscillator 2, and the total length of the slot 5 is one half of the wavelength corresponding to the notch central frequency.

The oscillator 2 is in an oval shape, a gap 5 is formed in the oscillator 2, the gap 5 is in an Contraband shape with an opening pointing to the microstrip feeder 3, the gap 5 is located in the middle of the oscillator 2, and the total length of the gap 5 is one half of the wavelength corresponding to the notch central frequency. In the ultra-wideband antenna 101 printed elliptical antenna 101, a part of the element 2 is appropriately clipped according to the current fringing characteristic of the antenna 101, and the influence on the impedance of the antenna 101 can be controlled within an acceptable range. The oscillator 2 is provided with a slot 5 with the total length corresponding to 1/2 wavelengths corresponding to the notch center frequency, so that the current under the corresponding notch frequency is concentrated at two ports of the slot 5, the currents at the two ports are opposite, the magnetic fields generated at the two ports are mutually cancelled, the original radiation characteristic of the antenna 101 is damaged, and the radiation of the antenna 101 in the frequency band is suppressed. Therefore, the method of forming the slot 5 in the elliptical element 2 can realize the notch function of the antenna 101 in the frequency band where interference exists in ultra-wideband communication, as shown in fig. 7.

The following is described in detail with reference to fig. 7:

in this embodiment, the substrate 1 is a substrate FR-4. The dielectric constant is 4.4, the thickness is 2mm, and the size of the vibrator 2 is favorably reduced. Making the antenna 101 smaller.

The vibrator 2 is oval, the long axis of the oval vibrator 2 is 16mm, and the short axis of the oval vibrator 2 is 9.5 mm. The smooth gradual change structure is beneficial to energy radiation and reduces reflection. The length of the substrate 1 is 43mm, the width is 32mm, and the impedance bandwidth of the VSWR <2 of the oscillator 2 is 3-10 Ghz.

Preferably, the microstrip feed line 3 is a 50 ohm microstrip line. Wherein the height h of the ground patch 4 is 24mm, and the distance between the ground patch 4 and the vibrator 2 is g 4 mm. The distance length is such that the return loss of the impedance bandwidth between the two resonance points is less than-10 db.

In the present embodiment, since the notch center frequency of the antenna 101 is 5.8GHz, the wavelength of 5.8GHz is about 52mm, and the half wavelength is about 26mm, the total length 2e + f of the slot 5 is 26 mm.

It should be noted that, although the above embodiments have been described herein, the invention is not limited thereto. Therefore, based on the innovative concepts of the present invention, the technical solutions of the present invention can be directly or indirectly applied to other related technical fields by making changes and modifications to the embodiments described herein, or by using equivalent structures or equivalent processes performed in the content of the present specification and the attached drawings, which are included in the scope of the present invention.

Claims

1. A novel combined type UWB electronic tags characterized in that includes: the system comprises an ultra-wideband antenna, a first duplexer, a second duplexer, a power amplifier, a low-noise amplifier, an attenuator and an MCU chip;

the attenuator is connected with the second duplexer;

the first duplexer is connected with the ultra-wideband antenna;

the MCU chip is connected with the first duplexer and the second duplexer;

2. The novel composite UWB electronic tag according to claim 1, further comprising: the system comprises a balun, a UWB chip, a Bluetooth chip, a ceramic antenna and a sensor module;

3. The new composite UWB tag of claim 1 wherein a wideband matching circuit is added between the UWB antenna and the first duplexer connection.

4. The new composite UWB tag of claim 1 wherein the power amplifier is of the GRF2101 type.

5. The novel composite UWB tag of claim 1 wherein the low noise amplifier is of the type BGB707L7 ESD.

6. The novel composite UWB tag of claim 1 wherein the attenuator comprises three resistors, the three resistors forming an RF attenuator in the shape of pi.

7. The new composite UWB tag of claim 1 wherein the substrate is a substrate FR-4;

the thickness of the substrate is 2 mm.

8. The novel composite UWB tag of claim 1 wherein the microstrip feed line is a 50 ohm microstrip line.

9. The novel composite UWB tag of claim 1 wherein the ground patch is spaced 0.1mm from the oscillator.