JP7244243B2 - antenna device - Google Patents

Description

The present invention relates to an antenna device.

For example, it is desirable that an antenna used in a radar device or the like has a low directivity ripple. Therefore, in Japanese Unexamined Patent Application Publication No. 2002-100000, a reflective portion and a blocking portion are provided around a plurality of array antennas to reduce directional ripples. The ripple referred to here is, for example, a phase shift (phase fluctuation) that occurs in actual directivity with respect to assumed directivity.

JP 2017-152850 A

Here, consider a case where two antennas are used in combination. One antenna and the other antenna each have their respective phase variations with respect to signal azimuth. However, when signals from two antennas are combined and used, for example, in transmission and reception, the antennas may be arranged such that the phase fluctuations of the signals of the antennas with respect to the azimuth angle reinforce each other. In this case, even if the phase fluctuation with respect to the azimuth angle of the signal is small for one antenna and the other antenna alone, there is a problem that the phase fluctuation becomes large due to signal processing using the signal obtained by combining each. occurs.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an antenna device capable of suppressing combined phase fluctuations obtained by combining phase fluctuations of signals from two antennas.

An antenna device according to the present invention comprises: a first antenna; a second antenna; a first passive radiation section that passively radiates radio waves by propagation from the first antenna; and a second passive radiating section that passively radiates radio waves due to the propagation of the distance between the first antenna and the first passive radiating section, and the distance between the second antenna and the second passive A configuration (first configuration).

In the antenna device having the first configuration, the first antenna may be a transmitting antenna for transmitting radio waves, and the second antenna may be a receiving antenna for receiving radio waves (second configuration). good.

In the antenna device having the first or second configuration, a substrate on which the first antenna and the second antenna are formed as conductive patterns is provided, and the first passive radiating section includes the second antenna of the substrate. A configuration in which a first open cross-sectional portion facing one antenna and the second passive radiation portion is a second open cross-sectional portion facing the second antenna of the substrate (third configuration) may be

In the antenna device having the first or second configuration, a substrate on which the first antenna and the second antenna are formed as conductive patterns is provided, and the first passive radiation section is formed on the substrate. a first suppressing portion facing the first antenna and suppressing propagation of a surface wave on the substrate; and the second passive radiation portion being formed on the substrate and facing the second antenna and facing the A configuration (fourth configuration) that is a second suppressing portion that suppresses the propagation of surface waves on the substrate may be employed.

In the antenna device having the first or second configuration, a substrate on which the first antenna and the second antenna are formed as conductive patterns is provided, and the first passive radiating section includes the second antenna of the substrate. 1 antenna, and the second passive radiation section is a suppressing section formed on the substrate, facing the second antenna, and suppressing propagation of a surface wave on the substrate. (Fifth configuration).

According to the present invention, it is possible to provide an antenna device capable of suppressing combined phase fluctuations obtained by combining phase fluctuations of signals from two antennas.

1 is a plan view of an antenna device according to a first embodiment; FIG. Sectional view of the antenna device according to the first embodiment Diagram showing simulation results Plan view of a modification of the antenna device according to the first embodiment Plan view of the antenna device according to the second embodiment Partial cross-sectional view of the antenna device according to the second embodiment Diagram showing simulation results Plan view of the antenna device according to the third embodiment Plan view of a modification of the antenna device according to the third embodiment The top view of the antenna device which concerns on 4th Embodiment Plan view of a modification of the antenna device according to the fourth embodiment Plan view of a modification of the antenna device according to the first embodiment Plan view of a modification of the antenna device according to the second embodiment

Exemplary embodiments of the invention are described in detail below with reference to the drawings.

<1. First Embodiment>
FIG. 1 is a diagram showing the configuration of an antenna device 101 (hereinafter referred to as antenna device 101) according to this embodiment. Antenna device 101 includes substrate 1 , first antenna 11 , and second antenna 12 . The first antenna 11 and the second antenna 12 are formed as conductive patterns on the surface of the substrate 1 facing the space in which radio waves are to be transmitted and received (hereinafter referred to as the surface).

The substrate 1 is a high-frequency substrate, and includes a synthetic resin such as fluororesin or epoxy resin, or a dielectric substrate layer such as a ceramic material, and has a plate shape.

The first antenna 11 includes a transmission line 11a for transmitting transmission signals or reception signals, and an antenna element 11b for transmitting (radiating) transmission waves or receiving reflections. The transmission line 11a has a substantially linear shape, and one end of the transmission line 11a is connected to an electronic circuit (not shown) via a wiring pattern (not shown), for example. A termination element 11c for suppressing reflection is provided at the other end of the transmission line 11a. Note that, unlike the present embodiment, the configuration may be such that the terminating element 11c is not provided.

A plurality of antenna elements 11b are connected to the sides of the transmission line 11a, and an array antenna is formed by the plurality of antenna elements 11b.

When the first antenna 11 functions as a transmission antenna for transmitting transmission waves, the transmission line 11a functions as a feed line for supplying power to each antenna element 11b, and the antenna elements 11b radiate transmission waves into space. Functions as a radiating element. When the first antenna 11 functions as a receiving antenna for receiving a received wave, the antenna element 11b functions as a receiving element for receiving the received wave, and the transmission line 11a serves as a power receiving element for transmitting the signal received by the receiving element 11b. function as a line.

The second antenna 12 has a structure similar to that of the first antenna 11 . Note that unlike the present embodiment, the first antenna 11 and the second antenna 12 may differ in the number of antenna elements, the presence or absence of a terminating element, and the like.

As shown in the cross-sectional view of FIG. 2 obtained by cutting along line segment AA in FIG. A portion 21 is formed. The ground part 21 is formed at least at a position facing the first antenna 11 and the second antenna 12 .

The substrate 1 has a pair of ends 1a and 1b extending along the longitudinal direction (Y-axis direction) of the first antenna 11 and facing the first antenna 11, and the longitudinal direction (Y-axis direction) of the second antenna 12. ) and a pair of ends 1 c and 1 d facing the second antenna 12 .

The ends 1a to 1d of the substrate 1 are open cross-sections open to the external space. The ends 1a and 1b of the substrate 1 serve as first passive radiation portions that receive surface waves propagating on the surface of the substrate 1 from the first antenna 11 and passively radiate radio waves. The ends 1c and 1d of the substrate 1 serve as second passive radiation portions that receive surface waves propagating on the surface of the substrate 1 from the second antenna 12 and passively radiate radio waves.

Here, the distance L1 between the center line of the first antenna 11 and the edge 1a of the substrate 1, the distance L2 between the center line of the first antenna 11 and the edge 1b of the substrate 1, and the distance L2 between the center line of the first antenna 11 and the edge 1b of the substrate 1 The relationship between the azimuth angle of the signal and the phase variation will be described with reference to the simulation results shown in FIG.

The azimuth angle (angle) of the signal of the first antenna 11 has the smallest absolute value (that is, 0°) when the direction of the transmitted wave or received wave coincides with the normal direction (Z-axis) of the substrate 1. , and the larger the incident angle of the transmitted wave or the received wave on the surface of the substrate 1 on the XZ plane, the greater the absolute value of the angle.

As shown in FIG. 3, by changing the distances L1 and L2, it is possible to change the variation characteristics of the phase error with respect to the azimuth angle of the signal of the first antenna 11. FIG. The phase error with respect to the azimuth angle of the signal of the first antenna 11 is the phase error that occurs in an ideal state in which there is no radiation of radio waves from anything other than the first antenna 11 . The phase variation with respect to the azimuth angle of the signal of the first antenna 11 is the variation of the phase error with respect to the azimuth angle of the signal of the first antenna 11 . Specifically, by lengthening the distances L1 and L2, it is possible to shorten the phase error fluctuation cycle (phase fluctuation cycle) with respect to the azimuth angle of the signal of the first antenna 11 .

Similarly, by changing the distances L3 and L4, the characteristics of the phase variation with respect to the azimuth angle of the signal of the second antenna 12 can be changed.

Therefore, in the antenna device 101, the distances L1 and L2 and the distances L3 and L4 are set to different values, and the phase fluctuation with respect to the azimuth angle of the signal of the first antenna 11 and the azimuth angle of the signal of the second antenna 12 are The distances L1 to L4 are set so that the phase fluctuations weaken each other through synthesis. Here, "the phase variation with respect to the azimuth angle of the signal of the first antenna 11 and the phase variation with respect to the azimuth angle of the signal of the second antenna 12 weaken each other by synthesis" means that to obtain a small phase variation. For example, the phase variation characteristic is smaller than at least one of the phase variations of the first antenna 11 alone and the phase variation of the second antenna 12 alone. Specifically, it means that the fluctuation amplitude of the phase error becomes smaller and the period of fluctuation of the phase error becomes longer. In other words, it is a phase variation characteristic that is advantageous in subsequent processing, such as angle calculation. For example, it is preferable to set the distances L1 to L4 so that the wave of the phase error shown in FIG. If the phase fluctuation of one antenna cannot be reduced due to layout restrictions or the like, the phase fluctuation obtained by combining may be smaller than the phase fluctuation of the other antenna but larger than the phase fluctuation of the other antenna. In addition, the above-mentioned "mutually weakening each other" means not only the case where each other weakens each other in the entire azimuth angle range, but also the case where each other strengthens each other in a part of the azimuth angle range. It also includes the case of weakening each other. If the combination of the value of the distance L1 and the value of the distance L2 does not match the combination of the value of the distance L3 and the value of the distance L4, the above setting can be performed. and the value of the distance L4.

By performing the setting described above, it is possible to suppress the synthesized phase variation obtained by synthesizing the phase variation of the signal of the first antenna 11 and the phase variation of the signal of the second antenna 12 . This makes it possible to suppress phase fluctuation in signal processing using the signal of the first antenna 11 and the signal of the second antenna 12 .

A slit may be provided in the substrate 1, and the slit may function as a passive radiating section that receives surface waves propagating on the surface of the substrate 1 from the antenna and passively radiates radio waves. FIG. 4 shows a configuration in which a step is not provided between the end portion 1a and the end portion 1c of the substrate 1, and a slit 1e is provided between the end portion 1a and the first antenna 11. FIG. In the configuration shown in FIG. 4, not only the end portion 1b of the substrate 1 and the inner surface S1 of the slit 1e, but also the outer surface S2 of the slit 1e receives the surface wave propagating on the surface of the substrate 1 from the first antenna 11 and passively receives the surface wave. It becomes the first passive radiating section that radiates radio waves in a targeted manner. Since there are more items to consider when designing the value of the distance between the slit 1e and the first antenna 11, the design becomes complicated.

<2. Second Embodiment>
FIG. 5 is a diagram showing the configuration of the antenna device 102 (hereinafter referred to as the antenna device 102) according to this embodiment. 5 that are the same as those in FIG. 1 are denoted by the same reference numerals.

The antenna device 102 includes a substrate 1, a first antenna 11, a second antenna 12, and EBG (Electromagnetic Band Gap) 31a to 31d. A first antenna 11 and a second antenna 12 are formed as conductive patterns on the surface of the substrate 1 .

Each of the EBGs 31a-31d comprises a plurality of patches 32 formed on the surface of the substrate 1 as conductive patterns.

Each patch 32 is electrically connected to the ground portion 21 via a through via 33, as shown in the partial cross-sectional view of FIG. 6 obtained by cutting along line segment BB in FIG.

The EBGs 31 a and 31 b are opposed to the first antenna 11 and serve as first suppressing portions that suppress propagation of surface waves propagating from the first antenna 11 on the surface of the substrate 1 . The EBGs 31 c and 31 d are opposed to the second antenna 12 and serve as second suppression portions for suppressing propagation of surface waves propagating on the surface of the substrate 1 from the second antenna 12 .

The EBGs 31a and 31b are located on the side directly facing the first antenna 11 of the patch 32 directly facing the first antenna 11 (opposing without another patch in between). receives surface waves propagating on the surface of the substrate 1 and passively radiates radio waves. The EBGs 31 c and 31 d are located on the side of the patch 32 directly facing the second antenna 12 (opposing without another patch in between) facing the second antenna 12 . receives the surface wave propagating on the surface of the substrate 1 and passively radiates radio waves.

Here, the relationship between the distance L5 between the center line of the first antenna 11 and the EBG 31a, the distance L6 between the center line of the first antenna 11 and the EBG 31b, and the phase variation with respect to the azimuth angle of the signal of the first antenna 11 will be described with reference to the simulation results shown in FIG.

The azimuth angle (angle) of the signal of the first antenna 11 has the smallest absolute value (that is, 0°) when the direction of the transmitted wave or received wave coincides with the normal direction (Z-axis) of the substrate 1. , and the larger the incident angle of the transmitted wave or the received wave on the surface of the substrate 1 on the XZ plane, the greater the absolute value of the angle.

As shown in FIG. 7, by changing the distances L5 and L6, it is possible to change the variation characteristics of the phase error with respect to the azimuth angle of the signal of the first antenna 11. FIG. The phase error with respect to the azimuth angle of the signal of the first antenna 11 is the phase error that occurs in an ideal state in which there is no radiation of radio waves from anything other than the first antenna 11 . The phase variation with respect to the azimuth angle of the signal of the first antenna 11 is the variation of the phase error with respect to the azimuth angle of the signal of the first antenna 11 . Specifically, by lengthening the distances L4 and L5, it is possible to shorten the phase error fluctuation cycle (phase fluctuation cycle) with respect to the azimuth angle of the signal of the first antenna 11 .

Similarly, by changing the distances L7 and L8, the characteristics of the phase variation with respect to the azimuth angle of the signal of the second antenna 12 can be changed.

Therefore, in the antenna device 102, the distances L5 and L6 and the distances L7 and L8 are set to different values, and the phase fluctuation with respect to the azimuth angle of the signal of the first antenna 11 and the azimuth angle of the signal of the second antenna 12 are The values of the distances L5 to L8 are set so that the phase fluctuations weaken each other through synthesis. If the combination of the value of the distance L5 and the value of the distance L6 does not match the combination of the value of the distance L7 and the value of the distance L8, the above setting can be performed. and the value of the distance L8.

By performing the setting described above, it is possible to suppress the synthesized phase variation obtained by synthesizing the phase variation of the signal of the first antenna 11 and the phase variation of the signal of the second antenna 12 . This makes it possible to suppress phase fluctuation in signal processing using the signal of the first antenna 11 and the signal of the second antenna 12 .

Further, unlike the antenna device 101, the antenna device 102 has no restrictions on the shape of the substrate 1, so that the degree of freedom in arranging components other than the antenna mounted on the substrate 1, for example, is improved.

<3. Third Embodiment>
FIG. 8 is a diagram showing the configuration of the antenna device 103 (hereinafter referred to as the antenna device 103) according to this embodiment. The antenna device 103 differs from the antenna device 101 in that it has three second antennas 12 to 12''.

In the antenna device 103, similarly to the antenna device 101, the distances L1 and L2 and the distances L3 and L4 are set to different values, and the phase fluctuation of the signal of the first antenna 11 with respect to the azimuth angle and the The values of the distances L1 to L4 are set so that the phase fluctuations with respect to the azimuth angles of the signals weaken each other through synthesis.

Further, in the antenna device 103, the distances L1 and L2 and the distances L3' and L4' are set to different values, and the phase fluctuation with respect to the azimuth angle of the signal of the first antenna 11 and the signal of the second antenna 12' The values of the distances L1, L2, L3', and L4' are set so that the phase variation with respect to the azimuth angle weakens each other through synthesis.

Further, in the antenna device 103, the distances L1 and L2 and the distances L3″ and L4″ are set to different values, and the phase fluctuation with respect to the azimuth angle of the signal of the first antenna 11 and the signal of the second antenna 12″ The values of the distances L1, L2, L3″, and L4″ are set so that the phase variations with respect to the azimuth angle weaken each other through synthesis.

For example, when the antenna device 103 is used in a radar device, the first antenna 11 may be used as a transmitting antenna, and the second antennas 12 to 12″ may be used as receiving antennas. Since the azimuth calculation of the target can be performed based on the phase difference between the three, and the phase fluctuation of the combined signal obtained by synthesizing the transmission signal and the reception signal can be suppressed, the accuracy of the azimuth calculation is improved. Since it is desirable that the second antennas 12 to 12″ have the same phase variation characteristics, the second antennas 12 to 12″ have the same shape, and the distance L3=distance L3′=distance L3″, and distance L4= It is desirable that the distance L4'=the distance L4''.

In addition, in the antenna device 103, the center lines CL of the three second antennas 12 to 12″ are not arranged on the same straight line, but they may be arranged on the same straight line. In order to shorten the length of the substrate 1 along the longitudinal direction of the antenna, for example, as shown in FIG. may be arranged along the lateral direction (X-axis direction) of the antenna.

In addition, although one transmitting antenna and three receiving antennas are used in this embodiment, the number of transmitting antennas and the number of receiving antennas are not limited to the example of this embodiment. For example, multiple transmission antennas may be used to realize MIMO (Multi-Input Multi-Output).

<4. Fourth Embodiment>
FIG. 10 is a diagram showing the configuration of an antenna device 104 (hereinafter referred to as antenna device 104) according to this embodiment. The antenna device 104 differs from the antenna device 102 in that it has three second antennas 12 to 12″, has EBGs facing the second antennas 12′ and 12″, and does not have EBGs 31a and 31b. .

In the antenna device 104, the distances L1 and L2 and the distances L7 and L8 are set to different values, and the phase fluctuation with respect to the azimuth angle of the signal of the first antenna 11 and the phase fluctuation with respect to the azimuth angle of the signal of the second antenna 12 The values of the distances L1, L2, L7, and L8 are set so that they weaken each other by synthesis.

Further, in the antenna device 104, the distances L1 and L2 and the distances L7' and L8' are set to different values, and the phase fluctuation with respect to the azimuth angle of the signal of the first antenna 11 and the signal of the second antenna 12' The values of the distances L1, L2, L7', and L8' are set so that the phase variation with respect to the azimuth angle weakens each other through synthesis.

Further, in the antenna device 104, the distances L1 and L2 and the distances L7'' and L8'' are set to different values, and the phase fluctuation with respect to the azimuth angle of the signal of the first antenna 11 and the signal of the second antenna 12'' The values of the distances L1, L2, L7″, and L8″ are set so that the phase variations with respect to the azimuth angles weaken each other through synthesis.

For example, when the antenna device 104 is used in a radar device, the first antenna 11 may be used as a transmitting antenna, and the second antennas 12 to 12″ may be used as receiving antennas. Since the azimuth calculation of the target can be performed based on the phase difference between the three, and the phase fluctuation of the combined signal obtained by synthesizing the transmission signal and the reception signal can be suppressed, the accuracy of the azimuth calculation is improved. Since it is desirable that the second antennas 12 to 12″ have the same phase variation characteristics, the second antennas 12 to 12″ have the same shape, and the distance L7=distance L7′=distance L7″, and distance L8= It is desirable that the distance L8'=the distance L8''.

In addition, in the antenna device 104, the center lines CL of the three second antennas 12 to 12″ are not arranged on the same straight line, but they may be arranged on the same straight line. In order to shorten the length of the substrate 1 along the longitudinal direction of the antenna, for example, as shown in FIG. may be arranged along the lateral direction (X-axis direction) of the antenna, in which case EBGs 31a and 31b facing the first antenna may be provided in order to increase the degree of freedom in the shape of the substrate 1.

<5. Others>
Various modifications can be made to the various technical features disclosed in this specification without departing from the gist of the technical creation in addition to the above-described embodiments. In addition, multiple embodiments and modifications shown in this specification may be implemented in combination to the extent possible.

For example, in the above-described embodiments, the longitudinal direction of the antenna and the end of the substrate facing the antenna are parallel, and the longitudinal direction of the antenna and the end of the EBG facing the antenna of the substrate are parallel. However, it is not limited to these. That is, the shape of the first passive radiating part that receives surface waves propagating on the surface of the substrate 1 from the first antenna 11 and passively radiates radio waves, and the surface that propagates on the surface of the substrate 1 from the second antenna 12 The shape of the second passive radiating portion that receives waves and passively radiates radio waves is arbitrary. For example, configurations as shown in FIGS. 12 and 13 may be used. In addition, when the distance between the first antenna 11 and the first passive radiating portion is not uniform, the average distance between the first antenna 11 and the first passive radiating portion is set to the average distance between the first antenna 11 and the first passive radiating portion. The distance from the passive radiating part of 1 may be set.

Further, the first passive radiation section may not face the first antenna 11 in the entire longitudinal direction, and the second passive radiation section may not face the second antenna 12 in the entire longitudinal direction. good.

1 substrate 1a-1d, 1c′, 1d′, 1c″, 1d″ end 11 first antenna 12, 12′, 12″ second antenna 31a-31d, 31c′, 31d′, 31c″, 31d″ EBG

Claims (6)

a first antenna;
a second antenna;
a first passive radiation unit passively radiating radio waves by propagation from the first antenna;
a second passive radiation unit that passively radiates radio waves by propagation from the second antenna;
with
the distance between the first antenna and the first passive radiation section and the distance between the second antenna and the second passive radiation section are different,
the phase variation with respect to the azimuth angle of the signal of the first antenna and the phase variation with respect to the azimuth angle of the signal of the second antenna weaken each other by combining;
The first antenna is a transmitting antenna that transmits radio waves, and the second antenna is a receiving antenna that receives radio waves,
antenna device. a substrate on which the first antenna and the second antenna are formed as conductive patterns;
the first passive radiation part is a first open cross-sectional part facing the first antenna of the substrate;
2. The antenna device according to claim 1 , wherein said second passive radiation portion is a second open cross-sectional portion of said substrate facing said second antenna. a first antenna;
a second antenna;
a first passive radiation unit passively radiating radio waves by propagation from the first antenna;
a second passive radiation unit that passively radiates radio waves by propagation from the second antenna;
a substrate on which the first antenna and the second antenna are formed as conductive patterns;
with
the distance between the first antenna and the first passive radiation section and the distance between the second antenna and the second passive radiation section are different,
the phase variation with respect to the azimuth angle of the signal of the first antenna and the phase variation with respect to the azimuth angle of the signal of the second antenna weaken each other by combining;
the first passive radiation part is a first open cross-sectional part facing the first antenna of the substrate;
the second passive radiation part is a second open cross-sectional part facing the second antenna of the substrate,
antenna device. a substrate on which the first antenna and the second antenna are formed as conductive patterns;
The first passive radiation section is a first suppressing section formed on the substrate, facing the first antenna, and suppressing propagation of a surface wave on the substrate,
2. The antenna device according to claim 1 , wherein said second passive radiation section is a second suppressing section which is formed on said substrate, faces said second antenna, and suppresses propagation of a surface wave on said substrate. a substrate on which the first antenna and the second antenna are formed as conductive patterns;
the first passive radiation part is an open cross-sectional part facing the first antenna of the substrate;
2. The antenna device according to claim 1 , wherein said second passive radiation section is a suppression section formed on said substrate, opposed to said second antenna, and configured to suppress propagation of a surface wave on said substrate. a first antenna;
a second antenna;
a first passive radiation unit passively radiating radio waves by propagation from the first antenna;
a second passive radiation unit that passively radiates radio waves by propagation from the second antenna;
a substrate on which the first antenna and the second antenna are formed as conductive patterns;
with
the distance between the first antenna and the first passive radiation section and the distance between the second antenna and the second passive radiation section are different,
the phase variation with respect to the azimuth angle of the signal of the first antenna and the phase variation with respect to the azimuth angle of the signal of the second antenna weaken each other by combining;
the first passive radiation part is an open cross-sectional part facing the first antenna of the substrate;
The second passive radiation section is a suppressing section formed on the substrate, facing the second antenna, and suppressing propagation of a surface wave on the substrate.
antenna device.

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