JP6747790B2 - Radar equipment - Google Patents

Description

The present invention relates to an antenna element having wide-angle directivity and a radar device.

A radar system that monitors a target in a wide angle has been conventionally developed. An antenna element having wide-angle directivity is disclosed in Patent Document 1, for example. A radar device having wide-angle directivity is disclosed in Patent Document 2, for example.

JP, 2013-110503, A JP, 2007-049691, A

The configuration of the antenna element of Patent Document 1 is shown in FIGS. 1 and 2. The antenna element 1 of Patent Document 1 includes a main body 11 and a dielectric layer 12. The main body 11 includes a transmission line/waveguide converter 111 and a horn opening 112. Although not shown in FIG. 1, as shown in FIG. 2, the dielectric layer 12 has a dielectric layer opening 121 formed therein.

The dielectric layer 12 has the function of a radome and is isolated from the transmission line/waveguide conversion unit 111 via the horn opening 112. The thickness of the dielectric layer 12 is 0.5 times the effective wavelength λ _g of the electromagnetic wave in the environment inside the dielectric layer 12 so that the reflection at the radome is reduced.

In this way, the dielectric layer 12 is isolated from the transmission line/waveguide conversion unit 111, which is a wave source of electromagnetic waves. Therefore, it can be considered that the electromagnetic wave radiated from the transmission line/waveguide conversion unit 111 enters the dielectric layer 12 in a substantially plane wave state.

In FIG. 1, the dielectric layer 12 does not have the dielectric layer opening 121. Then, of the electromagnetic waves that have entered the dielectric layer 12, the electromagnetic waves that have entered any location have substantially the same propagation distance inside the dielectric layer 12, and the phase delay due to the dielectric layer 12 is substantially the same. Therefore, the electromagnetic wave emitted from the dielectric layer 12 does not have wide-angle directivity.

In FIG. 2, the dielectric layer 12 has a dielectric layer opening 121 formed therein. The propagation distance inside the dielectric layer 12 is 0 and the phase delay due to the dielectric layer 12 is 0 for the electromagnetic wave incident on the dielectric layer 12 where the dielectric layer opening 121 is formed. .. On the other hand, with respect to the electromagnetic wave incident on the portion of the dielectric layer 12 where the dielectric layer opening 121 is not formed, the propagation distance inside the dielectric layer 12 is longer and the phase delay due to the dielectric layer 12 is larger. Therefore, the electromagnetic wave emitted from the dielectric layer 12 has wide-angle directivity.

As described above, in Patent Document 1, if the antenna element 1 is a horn antenna having a large individual size, even if the dielectric layer opening 121 is formed in the dielectric layer 12, the structure does not become complicated, and manufacturing is performed. Is easy. However, in Patent Document 1, if the antenna element 1 is a patch antenna or the like which has a small individual size and is formed in an array shape or a planar shape, if the dielectric layer opening 121 is formed in the dielectric layer 12, the structure is obtained. Is complicated and not easy to manufacture.

The configuration of the radar device of Patent Document 2 is shown in FIG. The radar device 2 of Patent Document 2 is composed of antenna planes 21, 22, 23 whose front directions are different from each other. The antenna planes 21, 22 and 23 are composed of transmission/reception antennas 211, 221, 231 respectively.

The transmission/reception antennas 211, 221, and 231 are targets that are capable of transmitting electromagnetic waves in a wide-angle direction to a certain extent centered on the front direction by appropriately selecting the type of antenna, and are targets that can be monitored. After the reflection of the electromagnetic wave of, the reflected wave is received.

As described above, in Patent Document 2, the antenna planes 21, 22, and 23 are in the wide-angle direction range to some extent with respect to the front direction, and the transmitting and receiving antennas 211, 221, and 231 are in the range in which they can be monitored. If so, the monitoring of the target by the radar device 2 is considered. However, in Patent Document 2, if the antenna planes 21, 22, and 23 are within the range of the dead angle direction that is largely deviated from the front direction, and the monitoring of the transmitting and receiving antennas 211, 221, and 231 is impossible, The target monitoring by the radar device 2 is not considered.

Therefore, in order to solve the above problems, the present invention provides (1) an antenna element having wide-angle directivity, which facilitates manufacturing without complicating the structure, and (2) a radar device having wide-angle directivity. In, the purpose is to extend the range in which monitoring is possible.

In order to achieve the above object, an antenna element conductor formed on the surface of a dielectric substrate is formed with a dielectric layer in close contact with or in close proximity to the electromagnetic wave radiated from the antenna element conductor. In this state, the dielectric layer is made incident. Then, for an electromagnetic wave incident on the dielectric layer at an incident angle of 0 degree, the propagation distance inside the dielectric layer is shorter and the phase delay due to the dielectric layer is smaller. On the other hand, for an electromagnetic wave incident on the dielectric layer at a finite incident angle, the propagation distance inside the dielectric layer is longer and the phase delay due to the dielectric layer is larger. Therefore, the electromagnetic wave emitted from the dielectric layer has a wide-angle directivity as compared with the electromagnetic wave when the dielectric layer is not provided.

Specifically, the present invention provides a dielectric substrate, a ground plane conductor formed on one surface of the dielectric substrate, an antenna element conductor formed on the other surface of the dielectric substrate, and the antenna element. And a dielectric layer formed on the surface of the conductor.

According to this configuration, even if the antenna element is a patch antenna or the like having a small individual size and formed in an array shape or a plane shape, in order to give the antenna element wide-angle directivity, It only needs to be formed in close contact with or close to the element conductor, the dielectric layer opening need not be formed in the dielectric layer, the structure is not complicated, and manufacturing is easy.

When the dielectric layer is formed in close contact with or close to the antenna element conductor, the effective dielectric in the surrounding environment of the antenna element conductor is more than that in the case where only the dielectric substrate is arranged without forming the dielectric layer. Since the efficiency is high, the antenna element conductor can be downsized while maintaining high radiation efficiency, and the antenna element can have wide-angle directivity.

Further, the present invention is the antenna element, wherein the thickness of the dielectric layer is 0.1 times or more the effective wavelength of an electromagnetic wave in the environment around the antenna element conductor.

According to this configuration, it is sufficient to change the propagation distance inside the dielectric layer and the phase delay due to the dielectric layer according to the incident angle inside the dielectric layer, and to make the antenna element have wide-angle directivity. ..

Further, the present invention is the antenna element, wherein the thickness of the dielectric layer is set so that the directivity of the antenna element does not cause a null in the front direction.

According to this configuration, it is possible to give the antenna element a wide-angle directivity to some extent and prevent the directivity null of the directivity of the antenna element from occurring.

Further, the present invention is the antenna element, wherein the thickness of the dielectric layer is 0.2 times or less the effective wavelength of an electromagnetic wave in the environment around the antenna element conductor.

According to this configuration, the antenna element has a wide-angle directivity to some extent, and the directivity of the antenna element is not null in the front direction.

In the present invention, the antenna elements described above are arranged linearly, and the single dielectric substrate, the single ground plane conductor, and the single dielectric layer are arranged linearly. And an array antenna shared by the antenna element conductors.

According to this configuration, the array antenna can be provided with wide-angle directivity while simplifying the manufacturing without complicating the structure and maintaining high radiation efficiency. In particular, a center-fed traveling-wave array antenna, which will be described later in the embodiment, has advantageous effects.

In the present invention, the antenna elements described above are arranged in a grid, and the single dielectric substrate, the single ground plane conductor, and the single dielectric layer are arranged in a grid. It is a planar antenna shared by the antenna element conductor of.

According to this configuration, the planar antenna can have wide-angle directivity while simplifying the manufacturing without complicating the structure and maintaining high radiation efficiency. In particular, a central feeding traveling wave type planar antenna, which will be described later in the embodiment, has advantageous effects.

Further, the present invention is a radar device comprising a plurality of antenna planes whose front directions are different from each other, in one of the antenna planes adjacent to each other, and the boundary of the antenna planes adjacent to each other. In the vicinity, the array antenna or the plane antenna described above is formed as a transmission antenna, and in the other antenna plane among the antenna planes adjacent to each other, the array antenna or the plane antenna described above is formed as a reception antenna. The radar device is characterized in that the electromagnetic wave transmitted from the transmitting antenna can be received by the receiving antenna after being reflected by a target.

According to this configuration, the transmitting antenna and the other antenna formed on the one antenna plane are provided even within the range of the blind spot direction largely deviating from the front direction of the one antenna plane and the other antenna plane which are adjacent to each other. The target can be monitored by the radar device as long as it is within a range where each of the receiving antennas formed on the antenna plane can be monitored.

By providing the transmitting antenna with wide-angle directivity, the number of elements of the transmitting antenna can be reduced and the cost of the radar device can be reduced. Further, it is possible to design a radar device having various uses and performances with a high degree of freedom, depending on the positions and types of the transmitting antenna and the receiving antenna on a plurality of antenna planes having different frontal directions.

As described above, according to the present invention, (1) an antenna element having a wide-angle directivity can be easily manufactured without complicating the structure, and (2) a radar device having a wide-angle directivity can be monitored. The range can be extended.

It is a figure which shows the structure of the antenna element of a prior art. It is a figure which shows the structure of the antenna element of a prior art. It is a figure which shows the structure of the radar apparatus of a prior art. It is a figure which shows the structure of the antenna element of this invention. It is a figure which shows the directivity of the antenna element of this invention. It is a figure which shows the directivity of the antenna element of this invention. It is a figure which shows the structure of the array antenna of this invention. It is a figure which shows the structure of the planar antenna of this invention. It is a figure which shows the structure of the radar apparatus of this invention.

Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiment described below is an example of implementation of the present invention, and the present invention is not limited to the following embodiment.

(Structure of antenna element)
The structure of the antenna element of the present invention is shown in FIG. The antenna element 3 of the present invention includes a dielectric substrate 31, a ground plane conductor 32, an antenna element conductor 33, and a dielectric layer 34. The ground plane conductor 32 is formed on one surface of the dielectric substrate 31. The antenna element conductor 33 is a patch antenna element conductor or the like, and is formed on the other surface of the dielectric substrate 31.

The dielectric layer 34 has a function of a radome and is formed in close contact with or close to the antenna element conductor 33. The thickness of the dielectric layer 34 depends on the environment around the antenna element conductor 33 so that the antenna element 3 has a wide-angle directivity and that the directivity of the antenna element 3 does not cause a null in the front direction. Is 0.1 times or more and 0.2 times or less of the effective wavelength λ _g of the electromagnetic wave.

In order to form the dielectric layer 34 in close contact with or close to the antenna element conductor 33, for example, after applying prepreg (adhesive) to the other surface of the dielectric substrate 31 and the surface of the antenna element conductor 33, A dielectric thin film substrate may be mounted. In this case, the total thickness of the dielectric thin film substrate and the prepreg (adhesive) is 0.1 times or more and 0.2 times or less of the effective wavelength λ _g of the electromagnetic wave in the environment around the antenna element conductor 33. It should be.

In this way, the dielectric layer 34 is in close contact with or close to the antenna element conductor 33, which is the wave source of electromagnetic waves. Therefore, it can be considered that the electromagnetic wave radiated from the antenna element conductor 33 is incident on the dielectric layer 34 in a substantially spherical wave state.

Then, for an electromagnetic wave incident on the dielectric layer 34 at an incident angle of 0 degree, the propagation distance inside the dielectric layer 34 is shorter and the phase delay due to the dielectric layer 34 is smaller. On the other hand, for an electromagnetic wave incident on the dielectric layer 34 at a finite incident angle, the propagation distance inside the dielectric layer 34 is longer and the phase delay due to the dielectric layer 34 is larger. Therefore, the electromagnetic wave emitted from the dielectric layer 34 has a wide-angle directivity as compared with the electromagnetic wave when the dielectric layer 34 is not provided.

The directivity of the antenna element of the present invention is shown in FIGS.

In FIG. 5, how the directivity of the antenna element of the present invention changes depending on the presence or absence of the dielectric layer 34 is simulated. Here, the ground plane conductor 32 is assumed to be finite. Then, it can be seen that the wide-angle directivity is better obtained when the dielectric layer 34 is provided (thickness 0.17λ _g ) than when the dielectric layer 34 is not provided.

In FIG. 6, it is simulated how the directivity of the antenna element of the present invention changes according to the thickness of the dielectric layer 34. Here, the ground plane conductor 32 is assumed to be infinite. _{Then, 0.10λ g, 0.15λ g, 0.17λ} g, 0.20λ g, 0.25λ g, as 0.30Ramuda _g, a dielectric layer 34 becomes thicker, the wide-angle directivity is obtained better I understand that. However, 0.20λ _g, 0.25λ _g, as 0.30Ramuda _g, a dielectric layer 34 becomes thicker, it can also be seen that the directivity of the front direction of the null occurs.

As shown in FIG. 5, the antenna element 3 has a wide-angle directivity by changing the propagation distance inside the dielectric layer 34 and the phase delay due to the dielectric layer 34 according to the incident angle inside the dielectric layer 34. to the thickness of the dielectric layer 34 is desirably 0.10Ramuda _g or more.

As shown in FIG. 6, in order to allow the antenna element 3 to have a wide-angle directivity to some extent and to prevent the front direction null of the directivity of the antenna element 3, the thickness of the dielectric layer 34 is It is preferably 0.20 λ _g or less, and more preferably about 0.17 λ _g .

As described above, even if the antenna element 3 is a patch antenna or the like which is small in size and is formed in an array shape or a planar shape, in order to give the antenna element 3 wide-angle directivity, the dielectric layer 34 is provided. It only needs to be formed in close contact with or close to the antenna element conductor 33, the dielectric layer opening need not be formed in the dielectric layer 34, the structure is not complicated, and manufacturing is easy.

When the dielectric layer 34 is formed in close contact with or close to the antenna element conductor 33, the surrounding of the antenna element conductor 33 is more likely to be formed than when only the dielectric substrate 31 is arranged without forming the dielectric layer 34. Since the effective permittivity in the environment increases, the antenna element conductor 33 can be downsized while maintaining high radiation efficiency, and the antenna element 3 can have wide-angle directivity. In particular, a center-fed traveling-wave array antenna has an advantageous effect.

(Structure of array antenna and plane antenna)
The structure of the array antenna of the present invention is shown in FIG. In the array antenna 4 of the present invention, the antenna elements 3 are arranged linearly, and the single dielectric substrate 31, the single ground plane conductor 32, and the single dielectric layer 34 are arranged linearly. It is shared by the antenna element conductor 33. The array antenna 4 described with reference to FIG. 7 is a center-feeding traveling-wave array antenna. The horizontal direction of the array antenna 4 is defined as the direction perpendicular to the extending direction of the array antenna 4. The vertical direction of the array antenna 4 is defined as a direction parallel to the extending direction of the array antenna 4.

The structure of the planar antenna of the present invention is shown in FIG. In the planar antenna 5 of the present invention, the antenna elements 3 are arranged in a grid, and the single dielectric substrate 31, the single ground plane conductor 32, and the single dielectric layer 34 are arranged in a grid. It is shared by the antenna element conductor 33. The planar antenna 5 described with reference to FIG. 8 is a center-feeding traveling-wave planar antenna. The horizontal direction of the plane antenna 5 is defined as the direction perpendicular to the extending direction of the array antenna 4. The vertical direction of the plane antenna 5 is defined as the direction parallel to the extending direction of the array antenna 4.

While the resonant wave type array antenna has a narrow band characteristic, the traveling wave type array antenna has a wide band characteristic, so that the traveling wave type array antenna is used for wide band applications. The inventor of the present application has found the following problems regarding the traveling wave array antenna.

That is, when all the antenna elements of the traveling wave array antenna are excited in the same phase, reflection occurs in the same phase from all the antenna elements, so that the reflection loss becomes large and the radiation efficiency becomes low at this frequency. On the other hand, when each antenna element of the traveling-wave array antenna is excited in a different phase, reflection occurs in a different phase from each antenna element, so radiation occurs in the direction tilted from the front direction, but the reflection loss in the wide band decreases. The radiation efficiency is high.

Then, when the traveling wave array antenna is fed at one end, when the operating frequency changes, the angle of the radiation direction with respect to the front direction changes. On the other hand, when the traveling wave array antenna is fed in the center, the angle of the radiation direction with respect to the front direction does not change even if the operating frequency changes. Therefore, when the traveling-wave array antenna is used in a wide band, the aim is to feed power in the center of the array.

When power is fed at the center of the array, it is necessary to maintain the vertical size of the array (that is, the number of antenna elements), as in the case of power feeding at one end of the array. In other words, when power is fed at the center of the array, two arrays each having a size in the vertical direction (that is, the number of antenna elements) of half are compared to the case where power is fed at one end of the array, with the power feeding section sandwiched. Will be formed.

Here, the traveling-wave array antenna radiates a part of the fed power in the antenna element near the power feeding section, and radiates a part of the remaining power in the antenna element far from the power feeding section, and the resistance at the end of the array. At, the remaining power is dissipated. Therefore, when the power is fed at the center of the array, the radiation efficiency is lower than when the power is fed at one end of the array.

When feeding in the center of the array, it is possible to increase the radiation amount of each antenna element in order to increase the radiation efficiency, as in the case of feeding at one end of the array, that is, widen the width of each antenna element. It is possible. However, the wider the width of each antenna element, the narrower the directivity of the array in the horizontal direction. The inventor of the present application has found that this poses a problem in applications such as radar where it is desired to extend the surveillance area.

Therefore, as shown in FIG. 7, by applying the antenna element 3 as the antenna element 41, the antenna element 41 can be downsized in the width direction while maintaining high radiation efficiency. Can have a wide-angle horizontal directivity.

Then, as shown in FIG. 7, by disposing the stubs 43 on the path of the transmission line 42, even when all the antenna elements 41 of the array antenna 4 are excited in the same phase, the same phase from all the antenna elements 41 Since it is difficult for reflection to occur at this frequency, the reflection loss becomes small at this frequency, the radiation efficiency becomes high, and the radiation occurs in the front direction.

Further, as shown in FIG. 7, by arranging the terminating element 44 at the end of the transmission line 42, the array antenna 4 radiates the electric power originally dissipated in the terminating resistor in the terminating element 44, The radiation efficiency can be further improved.

As shown in FIG. 7, the array antenna 4 is centrally fed by disposing the transmission line/waveguide conversion unit 45 in the central portion of the array antenna 4.

Further, in FIG. 8, the transmission line/waveguide conversion units 45 are arranged in a zigzag pattern in the horizontal direction of the planar antenna 5. Here, as a modification, the transmission line/waveguide conversion unit 45 may be linearly arranged in the horizontal direction of the planar antenna 5.

(Structure of radar device)
The structure of the radar device of the present invention is shown in FIG. The radar device 6 of the present invention is composed of antenna planes 61, 62, 63 whose front directions are different from each other. The antenna plane 61 is composed of a transmitting antenna 611 and a receiving antenna 612. The antenna plane 62 is composed of transmitting antennas 621 and 622 and a receiving antenna 623. The antenna plane 63 includes a transmitting antenna 631 and a receiving antenna 632.

In the antenna plane 62 of the antenna planes 61 and 62 adjacent to each other, and in the vicinity of the boundary between the antenna planes 61 and 62 adjacent to each other, the array antenna 4 or the planar antenna 5 shown in FIG. It is formed as an antenna 621. In the antenna plane 61 of the antenna planes 61 and 62 adjacent to each other and in the vicinity of the boundary between the antenna planes 61 and 62 adjacent to each other, the array antenna 4 or the planar antenna 5 shown in FIG. It is formed as an antenna 612.

The transmitting antenna 621 transmits electromagnetic waves in a wide-angle direction centered on the front direction of the antenna plane 62. The receiving antenna 612 receives the reflected wave in a wide-angle direction centered on the front direction of the antenna plane 61. The transmitting antenna 621 formed on the antenna plane 62 and the receiving antenna 612 formed on the antenna plane 61, respectively, even within the range of the blind spot direction largely deviated from the front direction of the antenna planes 61 and 62 adjacent to each other. The target T can be monitored by the radar device 6 if the target T is within the range.

In the antenna plane 62 of the antenna planes 62 and 63 that are adjacent to each other and in the vicinity of the boundary between the antenna planes 62 and 63 that are adjacent to each other, the array antenna 4 or the planar antenna 5 shown in FIG. It is formed as an antenna 622. In the antenna plane 63 of the antenna planes 62 and 63 adjacent to each other, and in the vicinity of the boundary between the antenna planes 62 and 63 adjacent to each other, the array antenna 4 or the planar antenna 5 shown in FIG. It is formed as an antenna 632.

The transmitting antenna 622 transmits electromagnetic waves in a wide-angle direction centered on the front direction of the antenna plane 62. The receiving antenna 632 receives the reflected wave in a wide-angle direction centered on the front direction of the antenna plane 63. The transmitting antenna 622 formed on the antenna plane 62 and the receiving antenna 632 formed on the antenna plane 63, respectively, even within the range of the blind spot direction largely deviated from the front direction of the antenna planes 62 and 63 adjacent to each other. The target T can be monitored by the radar device 6 if the target T is within the range.

The array antenna 4 or the planar antenna 5 shown in FIG. 7 or 8 is formed as the transmission antenna 611 in the antenna plane 61 and at a position away from the boundary between the antenna planes 61 and 62. The transmitting antenna 611 transmits an electromagnetic wave in a wide-angle direction centering on the front direction of the antenna plane 61, and the receiving antenna 612 receives a reflected wave in a wide-angle direction centering on the front direction of the antenna plane 61, and the radar device 6 Can monitor a target existing in a wide-angle direction centered on the front direction of the antenna plane 61.

The array antenna 4 or the planar antenna 5 shown in FIG. 7 or 8 is formed as the receiving antenna 623 at the antenna plane 62 and at a position away from the boundary between the antenna planes 61, 62, and 63. The transmission antennas 621 and 622 transmit electromagnetic waves in a wide-angle direction centered on the front direction of the antenna plane 62, and the reception antenna 623 receives reflected waves in a wide-angle direction centered on the front direction of the antenna plane 62, The device 6 can monitor a target existing in a wide-angle direction centered on the front direction of the antenna plane 62.

The array antenna 4 or the plane antenna 5 shown in FIG. 7 or 8 is formed as the transmission antenna 631 at the antenna plane 63 and at a position away from the boundary between the antenna planes 62 and 63. The transmitting antenna 631 transmits an electromagnetic wave in a wide-angle direction centered on the front direction of the antenna plane 63, and the receiving antenna 632 receives a reflected wave in a wide-angle direction centered on the front direction of the antenna plane 63, and the radar device 6 Can monitor a target existing in a wide-angle direction centered on the front direction of the antenna plane 63.

Thus, by providing the transmitting antennas 611, 621, 622, 631 with wide-angle directivity, the number of elements of the transmitting antennas 611, 621, 622, 631 can be reduced, and the cost of the radar device 6 can be reduced. be able to. Further, it has various applications and performances depending on the positions and types of the transmitting antennas 611, 621, 622, 631 and the receiving antennas 612, 623, 632 in the plurality of antenna planes 61, 62, 63 whose front directions are different from each other. The radar device 6 can be designed with a high degree of freedom. For example, by making the receiving antennas 612, 623, and 632 have a function of digital beam forming or monopulse angle measurement, not only the presence of the target but also the direction of the target can be measured.

INDUSTRIAL APPLICABILITY The antenna element, array antenna, planar antenna, and radar device according to the present invention can be applied in applications such as radar where it is desired to expand the surveillance area.

1: Antenna element 11: Main body 12: Dielectric layer 111: Transmission line/waveguide converter 112: Horn opening 121: Dielectric layer opening 2: Radar devices 21, 22, 23: Antenna planes 211, 221 , 231: Transmission/reception antenna 3: Antenna element 31: Dielectric substrate 32: Base conductor 33: Antenna element conductor 34: Dielectric layer 4: Array antenna 41: Antenna element 42: Transmission line 43: Stub 44: Termination element 45: Transmission Line/waveguide converter 5: Planar antenna 6: Radar devices 61, 62, 63: Antenna planes 611, 621, 622, 631: Transmission antennas 612, 623, 632: Reception antenna T: Target

Claims (7)

A radar device comprising a plurality of antenna planes whose front directions are different from each other,
In one of the antenna plane of the antenna plane adjacent to each other, and, in the vicinity of the boundary of the antenna plane adjacent to each other, transmit antennas is formed,
In addition to the antenna plane of the antenna plane adjacent to each other, receiving antennas are formed,
The electromagnetic wave transmitted from the transmitting antenna is received by the receiving antenna after being reflected by a target located within a range of a blind spot direction deviating from the front direction of each of the one antenna plane and the other antenna plane. A radar device characterized by being capable of The radar device according to claim 1, wherein at least one of the transmitting antenna and the receiving antenna is an array antenna in which antenna elements are linearly arranged. The radar device according to claim 1, wherein at least one of the transmitting antenna and the receiving antenna is a planar antenna in which antenna elements are arranged in a grid pattern. The antenna element includes a dielectric substrate, a ground plane conductor formed on one surface of the dielectric substrate, an antenna element conductor formed on the other surface of the dielectric substrate, and a surface of the antenna element conductor. And a dielectric layer formed,
4. The radar device according to claim 2, wherein a single dielectric substrate, a single ground plane conductor and a single dielectric layer are shared by a plurality of the antenna element conductors. .. The radar device according to claim 4 , wherein the thickness of the dielectric layer is 0.1 times or more an effective wavelength of an electromagnetic wave in an environment around the antenna element conductor. The radar device according to claim 4 or 5, wherein the thickness of the dielectric layer is set so that the directivity of the antenna formed by the antenna element conductor does not cause a null in the front direction. 7. The radar device according to claim 4 , wherein the thickness of the dielectric layer is 0.2 times or less the effective wavelength of an electromagnetic wave in the environment around the antenna element conductor. ..

Images