JP7415608B2 - Patch antenna, patch antenna manufacturing method - Google Patents

Description

The present invention relates to a patch antenna and a method for manufacturing a patch antenna.

In a patch antenna, a patch antenna element is arranged on a substrate. Usually, a plurality of patch antenna elements are arranged on a single substrate in a predetermined pattern, and therefore will be described below as a patch antenna.

This is achieved by adjusting the amount of radiated power and phase radiated into space from each patch antenna element in order to control antenna directivity in an array antenna consisting of multiple patch antenna elements installed on the same plane substrate. can.

The following control method can be considered as a method for controlling the amount of power radiated into space.

In other words, the amount of power to be fed is adjusted by a power distribution circuit that feeds power to the patch antenna element provided on the same plane board as each patch antenna element, and the radiation resistance of each patch antenna element is changed to radiate power into space. This control method involves controlling the amount of radiated power and antenna directivity radiated into space from the patch antenna element using a parasitic element that is not directly connected to a feeding circuit.

Patent Document 1 and Patent Document 2 describe a technique in which non-power feeding patches are provided on both sides of a patch antenna.

Moreover, Patent Document 3 describes a technique in which a non-feeding antenna is provided at a position facing each element of a planar antenna in the vertical direction and connected to a metal part, that is, GND.

Japanese Patent Application Publication No. 2017-188779 Japanese Patent Application Publication No. 2013-168875 Japanese Patent Application Publication No. 2004-328067

Here, there are various problems when mounting a plurality of patch antenna elements and a feed distribution circuit on the same planar substrate.

The line width of the microstrip line that constitutes the power supply distribution circuit is generally about 0.10 mm due to limitations on the etching accuracy of copper foil patterns in the board manufacturing process, and the amount of power distributed in the power supply distribution circuit is limited. There is a limit to the adjustment ratio.

In addition, controlling the amount of power radiated into space by changing the radiation resistance of each patch antenna element can be achieved by adjusting the width of the patch antenna element and the feeding position, but it is possible to control the amount of power radiated into space by changing the radiation resistance of each patch antenna element. This causes distortion in the antenna directivity, making it difficult to perform high-performance directivity control of the array antenna.

Furthermore, a method of controlling the amount of radiated power radiated into space from a patch antenna element and antenna directivity using a parasitic element is possible in principle with the structure of Patent Document 1 and Patent Document 2.

However, it is difficult to implement array antennas (series and parallel) in which a plurality of patch antenna elements and a feed distribution circuit are mounted on the same planar substrate due to physical constraints.

The present invention can alleviate the limitations of high-performance directivity design due to the restriction on the adjustment ratio of the distribution power of the feed distribution circuit, and can reduce all the components including a plurality of patch antenna elements and the feed distribution circuit. The purpose of the present invention is to obtain a patch antenna that can be mounted on the same plane of a substrate, and a method for manufacturing the patch antenna.

The patch antenna according to the present invention includes a plurality of patch antenna elements and a feed distribution circuit mounted on the same surface on the dielectric layer side, which is the surface of a flat substrate composed of a dielectric layer and a ground layer. , the short vias are arranged on the same surface of the planar substrate and correspond to a part of the plurality of patch antenna elements, and arranged so that the excitation direction is parallel to the excitation direction of the patch antenna elements, and The device is characterized in that it has a radiation power control element electrically connected to the ground layer on the back surface side using a radiated power control element.

The patch antenna according to the present invention includes a plurality of patch antenna elements and a feed distribution circuit mounted on the same surface on the dielectric layer side, which is the surface of a flat substrate composed of a dielectric layer and a ground layer. is arranged on the same surface of the planar substrate so that the excitation direction is parallel to the excitation direction of the patch antenna element, and is electrically connected to the ground layer on the back side using short vias. The radiated power control element has a connected radiated power control element, and when the effective wavelength in the planar substrate at the operating frequency is λg, the radiated power control element has an electrical length in the excitation direction greater than 0.217λg and equal to or less than 0.333λg. , the electrical length in the direction orthogonal to the excitation direction is set to 0.042λg or more and 0.125λg or less, and the minimum distance between the end of the patch antenna element and the end of the radiated power control element is 0. It is characterized by being set to .083λg or more and 0.1λg or less.

A method for manufacturing a patch antenna according to the present invention includes mounting a plurality of patch antenna elements and a feed distribution circuit on the same surface on the dielectric layer side, which is the surface of a flat substrate composed of a dielectric layer and a ground layer. A radiated power control element is arranged on the same surface of the planar substrate so that the excitation direction is parallel to the excitation direction of the patch antenna element, and one end of the electrical length of the radiated power control element in the excitation direction is By penetrating the dielectric layer of the planar substrate with a short via attached to it, it is electrically connected to the ground layer on the back side, and when the effective wavelength in the planar substrate at the operating frequency is λg, The electrical length of the radiation power control element in the excitation direction is set to be greater than 0.217λg and less than or equal to 0.333λg, the electrical length in the direction orthogonal to the excitation direction is set to be greater than or equal to 0.042λg and less than or equal to 0.125λg, and the The present invention is characterized in that the minimum distance between the end of the patch antenna element and the end of the radiation power control element is set to 0.083λg or more and 0.1λg or less.

As described above, the present invention can alleviate the limitations of high-performance directivity design due to the restriction on the adjustment ratio of the distribution power of the feed distribution circuit, and can include a plurality of patch antenna elements and the feed distribution circuit. This has the effect that all components can be mounted on the same plane of the board.

FIG. 2 is a perspective view of a series-fed patch array antenna with a linear eight-element array arrangement according to the present embodiment. 2 is a partially enlarged view of the serially fed patch array antenna in FIG. 1, and is a perspective view of a wiring pattern provided with a feed power distribution control circuit that determines the adjustment ratio of feed power in a linear 8-element array arrangement. 3 is an enlarged perspective view of the feeding power distribution control circuit shown in FIG. 2. FIG. FIG. 2 is an enlarged perspective view of a patch antenna element attached to the series-fed patch array antenna shown in FIG. 1 and its surroundings. FIG. 3 is a diagram showing radiated power gain characteristics for each dimension (Gap) between the patch antenna element and the radiated power control element according to the present embodiment and the length in the excitation direction of the radiated power gain control element. FIG. 3 is a diagram of radiation power gain characteristics with respect to directivity angles for each length (L) in the excitation direction in the radiation power control element according to the present embodiment. FIG. 7 is a perspective view of a parallel feeding patch array antenna according to a modification.

FIG. 1 shows a series-fed patch array antenna 10 having a linear eight-element array arrangement according to the present embodiment.

In the series-fed patch array antenna 10, a plurality of patch antenna elements 14 (only some of them are indicators in FIG. 1) are arranged on a flat substrate 12. A GND layer 12G is provided on the entire back surface of the flat substrate 12.

Further, as shown in FIG. 2, a plurality of feeding power distribution control circuits 16 are mounted on the same plane of the flat substrate 12. The series-fed patch array antenna 10 according to this embodiment is used as a 79 GHz band antenna.

As shown in FIG. 1, when power is supplied from the power supply section 18 of the planar substrate 12, the power is supplied to each wiring pattern 20 of the linear eight-element array arrangement via the power supply distribution control circuit 16 having different characteristics.

The 79 GHz band series-fed patch array antenna 10 uses a flat substrate 12 with a frequency of 1/16λg to 1/64λg (λg is the effective wavelength on the flat substrate 12, in order to suppress antenna radiation efficiency and resonance of higher-order modes. A Teflon (registered trademark) substrate material (thickness: 0.2 mm) with a thickness of about 2.4 mm or more (thickness of the dielectric layer) is applied.

As shown in FIG. 3, the line width of the microstrip line 16A constituting the feeding power distribution control circuit 16 is limited by the etching accuracy of the copper foil pattern during the board manufacturing process.

Therefore, the line width of the microstrip line 16A that can generally be manufactured is about 0.1 mm.

Therefore, there is a limit to the adjustment ratio of the amount of distributed power by the feeding power distribution control circuit 16 due to limitations on processing accuracy. For example, when the above planar substrate 12 is used, the characteristic impedance of the microstrip line 16A with a line width of 0.1 mm is about 100Ω, and the adjustment ratio of the distributed power amount is 4.8 dB or less at maximum.

In this embodiment, the radiation power control element 22 (see FIGS. 1 and 4) is employed in order to achieve an adjustment ratio of 4.8 dB or more.

As shown in FIG. 1, the patch antenna element 14 is composed of a square copper foil pattern with a side of about 1.1 mm, and a plurality of patch antenna elements 14 are electrically connected in series to each of eight linear wiring patterns. It is connected.

As shown in FIG. 4, in the patch antenna element 14, the radiation power control elements 22 are arranged so as to face two sides intersecting a direction perpendicular to the excitation direction.

The radiation power control element 22 has a conductive plate shape and includes a short via 20A that penetrates the flat substrate 12. Short vias 20A penetrating the planar substrate 12 are electrically connected to a GND layer 12G provided on the back surface.

In the following, the gap size between the patch antenna element 14 and the radiated power control element 22 is referred to as Gap, and the length of the radiated power control element 22 in the excitation direction is referred to as L (see FIG. 4). Further, as shown in FIG. 1, let P be the interval between adjacent patch antenna elements 14 in the array arrangement, and M be the pitch (spatial wavelength) between the patch antenna elements 14.

Further, as shown in FIG. 1, when the distance M between adjacent patch antenna elements 14 in the array arrangement is the spatial wavelength P=0.65λ (λ≒3.8 mm), the radiation power control element 22 The distance between the patch antenna elements 14 is 1.4 mm, and the radiation power control element 22 is arranged between the patch antenna elements 14 at a distance of 1.4 mm (≈0.65×3.8).

The radiation power control element 22 is configured to receive a portion of the power radiated from the patch antenna element 14 and radiate it.

In this embodiment, by adjusting the dimensions (mainly the length L in the excitation direction) and position (mainly the gap dimension Gap between the radiation power control element 22 and the radiation power control element 22), the radiation power control element 22 can be adjusted. The phase of the radiation power from the patch antenna element 14 and the radiation power from the patch antenna element 14 are set.

That is, the radiation power control element 22 has a function of controlling the radiation power of the patch antenna element 14.

Note that the gap dimension Gap between the radiation power control element 22 and the patch antenna element 14 is set to be at least a distance equivalent to 0.2 mm, which is the thickness of the planar substrate 12, so that the performance of the patch antenna element 14 alone is affected. The influence is almost eliminated, and control of the radiation power of the patch antenna element 14 as a single unit becomes stable.

Although the width dimension W of the radiation power control element 22 has almost no influence on the control of radiation power, in this embodiment, considering the physical limitations when mounting on the flat substrate 12, W=0. It was set to 2 mm (0.083λg). Note that the width of the radiated power control element 22 may be other than the above if there is sufficient mounting space on the flat substrate 12.

(Adjustment criteria for dimensions and position of radiated power control element 22)

According to FIGS. 5 and 6, the dimensions and position of the radiated power control element 22 are analyzed with respect to the adjustment criteria.

FIG. 5 is a radiated power gain characteristic diagram with respect to the length in the excitation direction of the radiated power gain control element for each dimension (Gap) between the patch antenna element 14 and the radiated power control element 22 according to the present embodiment.

Moreover, FIG. 6 is a radiated power gain characteristic diagram with respect to the directivity angle for each excitation direction length (L) in the radiated power control element 22 according to the present embodiment.

As shown in FIG. 5, by keeping the gap size Gap between the radiation power control element 22 and the radiated power control element 22 at a distance of 0.5 mm (when the length L in the excitation direction is equal to or greater than 0.58 mm (0.242λg)), approximately It can be seen that there is no influence on the radiation power gain of the patch antenna element 14.

Further, as shown in FIG. 6, the excitation direction of the radiated power control element 22 may have a length L = 0.52 mm (0.217 λg) or more and a length L = 1.1 mm (0.458 λg) or less. It can be seen that there is almost no effect on the directivity (indentation near the directivity angle of 0 degrees).

The interval between adjacent patch antenna elements 14 is 1.4 mm, and when radiating power control element 22 is arranged between this interval (1.4 mm), the radiated power control element 22 is placed next to the patch antenna element 14 that is subject to radiated power control. If the radiation power control element 22 is placed with a distance of 0.5 mm (0.208λg) or more from the neighboring patch antenna element placed in the area, the adjacent radiation power control element 22 will not be affected. Not affected.

Therefore, it is desirable to adjust the dimensions and position of the radiation power control element 22 within the range of Gap=0.2 mm to 0.3 mm (0.083λg to 0.125λg).

In this embodiment, Gap is set to 0.2 m to 0.24 mm (0.083 λg to 0.1 λg), and radiation is emitted in the range of L = 0.52 mm to 0.8 mm (0.217 λg to 0.333 λg). By adjusting the dimensions and position of the power control element 22, the radiation power gain of the patch antenna element 14 can be adjusted within the range of -0.68 dB to -10 dB.

The operation of this embodiment will be explained below.

The power fed to the patch antenna element 14 is radiated from the patch antenna element 14 into space.

A part of the radiation radiated into the space feeds the radiation power control element 22 disposed near the patch antenna element 14 through electromagnetic coupling, and is radiated from the radiation power control element 22 into the space.

The radio waves radiated into space from the radiated power control element 22 are configured to be spatially combined with the radio waves radiated from the patch antenna element 14 with different phases, and the radiated power of the patch antenna element 14 is controlled. be able to.

To adjust the radiation power, the amount of electromagnetic coupling is adjusted by the gap size Gap between the patch antenna element 14 and the radiation power control element 22, and the radiation power of the radiation power control element 22 at a desired frequency is adjusted by the length L of the radiation power control element 22. This is achieved by adjusting the gain.

Here, as mentioned above, in this embodiment, Gap=0.2m to 0.24mm (0.083λg to 0.1λg), and L=0.52mm to 0.8mm (0.217λg to By adjusting the dimensions and position of the radiated power control element 22 within the range of 0.333λg), the radiated power gain of the patch antenna element 14 can be adjusted within the range of -0.68 dB to -10 dB.

For example, as shown in Fig. 2, in the adjustment ratio of the feeding power of a linear 8-element array, the low sidelobe level is -32 dB (aperture excitation distribution f(x) = cos ⁿ (πx/D), n = 2). When designing the array antenna directivity using a distribution circuit with a linear 8-element array arrangement, the feeding power distribution control circuit 16 needs to be designed with a feeding power adjustment ratio of 5.5 dB (10 dB - 4.5 dB). .

However, due to limitations in processing accuracy, it is difficult to obtain performance with a feeding power adjustment ratio of 4.8 dB or more.

Therefore, in this embodiment, the radiated power control element 22 (Gap=0.24 mm, L=0.8 mm) is used to compensate for the insufficient adjustment ratio of 0.7 dB of the feeding power.

In this embodiment, the adjustment ratio of the feeding power is set to 5.5 dB, but adjustment by the radiation power control element 22 is also possible when designing a directional antenna with higher performance and a low sidelobe level.

Further, as shown in FIG. 1, in the series-fed patch array antenna 10 equipped with the radiated power control element 22, power control is not performed by the radiated power control element 22 on the patch antenna element 14 near the center, and on the periphery. The power of the patch antenna element 14 is controlled by a radiation power control element 22. Thereby, a patch array antenna in which a plurality of patch antenna elements 14 and a feeding power distribution control circuit 16 are arranged on the same plane of the flat substrate 12 can be realized while maintaining the antenna mounting area.

As described above, in this embodiment, the radiation power of the patch antenna element 14 is controlled by the radiation power control element 22 arranged near each patch antenna element 14 in the series-fed patch array antenna 10 having a linear eight-element array arrangement. By controlling this, it is possible to alleviate the limitations of high-performance array antenna directivity design due to limitations on the adjustment ratio of the distribution power of the feeding power distribution control circuit 16.

Furthermore, it is possible to mount each of the plurality of patch antenna elements 14 , the feeding power distribution control circuit 16 , and the radiation power control element 22 arranged near each patch antenna element 14 on the same plane of the flat substrate 12 . can.

Although this embodiment has been described using the series-fed patch array antenna 10 (see FIG. 1) as an example, the radiated power control technique by arranging the radiated power control element 22 near the patch antenna element 14 according to the present invention is also applicable. As shown in FIG. 7, this can also be applied to a parallel-fed patch array antenna 10A.

Although preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person with ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea stated in the claims. It is understood that these also naturally fall within the technical scope of the present invention.

10 Series feeding patch array antenna 12 Planar substrate 12G GND layer 14 Patch antenna element 16 Feeding power distribution control circuit 16A Microstrip line 18 Feeding section 20 Wiring pattern 22 Radiation power control element 20A Short via 10A Parallel feeding patch array antenna (modified example)

Claims (6)

In a patch antenna in which a plurality of patch antenna elements and a feed distribution circuit are mounted on the same surface on the dielectric layer side, which is the surface of a planar substrate composed of a dielectric layer and a ground layer,
arranged on the same surface of the planar substrate and corresponding to a part of the plurality of patch antenna elements, arranged so that the excitation direction is parallel to the excitation direction of the patch antenna elements, and using short vias. A patch antenna having a radiation power control element electrically connected to the ground layer on the back side. In a patch antenna in which a plurality of patch antenna elements and a feed distribution circuit are mounted on the same surface on the dielectric layer side, which is the surface of a planar substrate composed of a dielectric layer and a ground layer,
arranged on the same surface of the planar substrate, arranged so that the excitation direction is parallel to the excitation direction of the patch antenna element, and electrically connected to the ground layer on the back side using short vias. It has a radiated power control element,
When the effective wavelength in the planar substrate at the operating frequency is λg, the radiated power control element has an electrical length in the excitation direction set to be greater than 0.217λg and equal to or less than 0.333λg, and a direction perpendicular to the excitation direction. The electrical length of is set to 0.042λg or more and 0.125λg or less, and the minimum distance between the end of the patch antenna element and the end of the radiated power control element is set to 0.083λg or more and 0.1λg or less. , patch antenna. 3. The patch antenna according to claim 1, wherein the combination of the patch antenna element and the radiation power control element is formed in a predetermined arrangement pattern and constitutes a patch array antenna that functions as a single patch antenna as a whole. 4. The patch antenna according to claim 1, wherein in the radiation power control element, two radiation power control elements are arranged with the patch antenna element sandwiched therebetween. 5. The patch antenna according to claim 1, wherein the normalized radiated power gain that can be controlled by the radiated power control element is from -0.68 dB to -10 dB. A plurality of patch antenna elements and a power distribution circuit are mounted on the same surface on the dielectric layer side, which is the surface of a flat substrate composed of a dielectric layer and a ground layer,
A radiation power control element is arranged on the same surface of the planar substrate so that the excitation direction is parallel to the excitation direction of the patch antenna element,
A short via attached to one end of the electrical length in the excitation direction in the radiation power control element is passed through the dielectric layer of the planar substrate to be electrically connected to the ground layer on the back side,
When the effective wavelength in the planar substrate at the operating frequency is λg, the electrical length of the radiated power control element in the excitation direction is set to be greater than 0.217λg and less than or equal to 0.333λg,
The electrical length in the direction orthogonal to the excitation direction is set to 0.042λg or more and 0.125λg or less,
A method for manufacturing a patch antenna, wherein a minimum distance between an end of the patch antenna element and an end of the radiation power control element is set to 0.083λg or more and 0.1λg or less.