JP2021005816A - Planar array antenna shared between transmission and reception - Google Patents

Abstract

To provide a planar array antenna shared between transmission and reception that can reduce a grating lobe without increasing the thickness and weight to improve a front gain.SOLUTION: An inter-element non-feeding element substrate 62 in which inter-element non-feeding patches 62b which are non-feeding elements extending in an excitation direction of transmission patches 42b of an upper layer feeding element substrate 42 are respectively arranged between the transmission patch 42b and the transmission patch 42b is stacked on the upper side of the upper layer feeding element substrate 42, and the dimension of the inter-element non-feeding patches 62b and the height of the inter-element non-feeding element substrate 62 with respect to the upper layer feeding element substrate 42 are set so that the grating lobe generated in the upper layer feeding element substrate 42 is canceled by the grating lobe generated in the inter-element non-feeding element substrate 62.SELECTED DRAWING: Figure 1

Description

The present invention relates to a transmission / reception shared plane array antenna capable of transmitting and receiving two polarization signals orthogonal to each other.

In microwave band satellite communication, it is necessary to switch between vertically polarized light and horizontally polarized light for each receiving channel, so one antenna can handle two orthogonally polarized waves (vertically polarized light and horizontally polarized light). A common plane array antenna for transmission and reception is used. As shown in FIG. 7, the conventional transmission / reception shared plane array antenna has a ground plate 101, a dielectric 102, a lower layer feeding element substrate 103, a dielectric 104, a lower layer slot plate 105, a dielectric 106, and an upper layer feeding element in this order from the lower layer. The substrate 107, the dielectric 108, and the upper slot plate 109 are laminated.

In the lower layer feeding element substrate 103, rectangular lower layer feeding elements 103b made of a conductive foil are arranged in a matrix on the lower layer feeding substrate 103a having an insulating property. Similarly, in the upper layer feeding element substrate 107, a rectangular upper layer feeding element 107b made of a conductive foil is arranged at the same position as the lower layer feeding element 103b on the upper layer feeding substrate 107a having an insulating property.

The size of the feeding element is determined according to the frequency band of the polarization signal to be transmitted and received, and the lower the frequency band, the larger the size of the feeding element. Therefore, when the frequency bands of the transmitted polarization signal and the received polarization signal are far apart, for example, there is a difference in size between the lower layer feeding element 103b and the upper layer feeding element 107b, and the size is large. The arrangement interval is determined according to the feeding element. Therefore, in a power feeding element having a small size, the arrangement interval in the excitation direction becomes larger than necessary with respect to the wavelength λ of the polarization signal, and a grating lobe is generated. As a result, there is a problem that energy is taken away by the grating lobe and the front gain is lowered.

On the other hand, there is known a technique of reducing the level of the grating lobe by providing a metal flare (horn) for each transmission / reception flat antenna element (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-175680

However, the technique of Patent Document 1 has a problem that the transmission / reception shared plane array antenna becomes significantly thicker and the weight also increases.

Therefore, an object of the present invention is to provide a transmission / reception shared plane array antenna capable of improving frontal gain by reducing the grating lobe without increasing the thickness and weight.

In order to solve the above problems, the invention according to claim 1 comprises a transmission board in which a plurality of feeding elements for transmitting a polarization signal are arranged in a matrix, and a plurality of transmission boards for receiving the polarization signal. A receiving board in which the feeding element is arranged at the same position as the feeding element of the transmitting board is provided, the receiving board is laminated under the transmitting board, and two polarization signals orthogonal to each other are transmitted and received. An inter-element power feeding element, which is a flat array antenna and is a non-feeding element extending in the excitation direction of the feeding element of the transmitting board, is arranged between the feeding element and the feeding element. The dimensions of the inter-element power supply element and the transmission so that the substrate is laminated on the upper side of the transmission board and the grating lobe generated on the transmission board is canceled by the grating lobe generated on the inter-element power supply non-feeding element substrate. The height of the inter-element non-feeding element substrate with respect to the substrate is set.

According to the invention of claim 1, since the inter-element power feeding non-feeding elements are arranged between the feeding elements and the inter-element feeding non-feeding elements, the arrangement interval of the inter-element feeding non-feeding elements is the same as the arrangement spacing of the feeding elements. No power supply between the substrate and the element The grating lobes generated in the element substrate are in the same angular direction. Then, the dimensions of the inter-element non-feeding element and the height of the inter-element non-feeding element substrate with respect to the transmitting substrate are set so that the grating lobe generated on the transmission board is canceled by the grating lobe generated on the inter-element non-feeding element substrate. Therefore, it is possible to reduce the grating lobe and improve the frontal gain. Further, since the element-to-element non-feeding element substrates in which the inter-element feeding elements are arranged are merely laminated, the thickness and weight are not significantly increased.

It is an exploded perspective view which shows the laminated structure of the transmission / reception common plane array antenna which concerns on embodiment of this invention. It is a figure (a) which shows the polarization plane of the transmission / reception common plane array antenna of FIG. 1, and the explanatory view (b) which shows an angle of an observation direction. It is a figure which shows the positional relationship between the transmission patch of the transmission / reception common plane array antenna of FIG. 1 and the feeding patch between elements. It is a figure which shows the transmission directivity of the transmission / reception common plane array antenna which contrasts with the transmission / reception common plane array antenna of FIG. 1, (a) shows the transmission directivity of the peripheral angle region of a Z axis, (b) is a wide angle region. Indicates the transmission directivity of. It is a figure which shows the front surface gain and the aperture efficiency in the transmission / reception common plane array antenna which contrasts with the transmission / reception common plane array antenna of FIG. It is a figure which shows the frontal gain with respect to the frequency in the transmission / reception common plane array antenna which contrasts with the transmission / reception common plane array antenna of FIG. It is an exploded perspective view which shows the laminated structure of the conventional transmission / reception common plane array antenna.

Hereinafter, the present invention will be described based on the illustrated embodiment.

1 to 6 show an embodiment of the present invention, and FIG. 1 is an exploded perspective view showing a laminated structure of a transmission / reception shared plane array antenna (hereinafter, referred to as “the present array antenna”) 1 according to the present embodiment. Is. The array antenna 1 is an array antenna that transmits and receives two polarization signals (horizontal polarization and vertical polarization) that are orthogonal to each other in microwave band satellite communication, and is rectangular as shown in FIG. 2A. A large number of antenna elements (reception patch 26b, transmission patch 42b, etc., which will be described later) are arranged in a matrix along the X-axis and Y-axis orthogonal to each other on the plane of the plate-shaped antenna main body 11.

In this array antenna 1, when the direction of the observation plane for transmitting and receiving polarization signals (observation plane angle) is φ = 0 ° with respect to the X axis, the transmission polarization plane is φ = 45 ° and the reception polarization plane is φ =. It is 135 °. FIG. 2B shows the observation directions of the satellite on the X-axis and the Y-axis and the Z-axis orthogonal to them (the paper depth direction of FIG. 2A), and this observation direction is projected on the XY plane. The angle formed by the projected line and the X-axis is the observation plane angle φ, and the angle formed by the observation direction and the Z-axis is the observation angle θ.

The array antenna 1 includes an upper layer feeding element substrate (transmission substrate) 42 in which a plurality of transmission patches (feeding elements) 42b for transmitting a polarization signal are arranged in a matrix, and a plurality of transmission patches (feeding elements) 42 for receiving the polarization signal. The receiving patch (feeding element) 26b of the above is provided with a lower layer feeding element substrate (receiving board) 26 arranged at the same position as the transmitting patch 42b. Specifically, the first laminated portion 2 and the second are in order from the lower layer. The laminated portion 3, the third laminated portion 4, the fourth laminated portion 5, the fifth laminated portion 6, the sixth laminated portion 7, and the seventh laminated portion 8 are laminated.

In the first laminated portion 2, the lower cover 21, the base plate 22, the foamed sheet (dielectric) 23, the ground plate 24, the foamed sheet 25, and the lower layer feeding element substrate 26 are laminated in this order from the lower layer. The foamed sheets 23 and 25 are sheet materials of polyethylene foam or polypropylene foam, and the same applies to other foamed sheets described later. Further, the ground plate 24 is a shielding plate for shielding and is made of a thin plate having conductivity, for example, an aluminum plate, and the same applies to the lower layer slot plate 32 and the upper layer slot plate 52 described later.

The lower layer feeding element substrate 26 is a substrate in which reception patches 26b for receiving polarization signals are arranged in a matrix. That is, a thin lower layer feeding board 26a having an insulating property such as a flexible substrate, a plurality of rectangular receiving patches 26b arranged at predetermined intervals on the lower layer feeding board 26a, and a lower layer feeding line 26c that supplies power to the receiving patches 26b. And. The receiving patch 26b and the lower layer feeding line 26c are formed of a conductive foil such as copper, aluminum, or gold. Further, the lower layer feeding line 26c extends along a predetermined direction and is connected to a common feeding trunk line on the lower layer feeding board 26a.

In the second laminated portion 3, the foam sheet 31 and the lower layer slot plate 32 are laminated in this order from the lower layer. The lower layer slot plate 32 is provided with a rectangular slot opening 32a at a position facing each receiving patch 26b. Further, the slot opening 32a is provided with a bridge portion 32b that crosses the diagonal direction. The bridge portion 32b is provided in parallel with the excitation direction of the transmission patch 42b, which will be described later, and when the transmission patch 42b is fed, it exerts a strong influence on the excitation and improves antenna characteristics such as directivity. Further, since it is orthogonal to the excitation direction of the reception patch 26b and its width is sufficiently narrower than that of the reception patch 26b, there is almost no effect thereof and other antenna characteristics are not deteriorated.

In the third laminated portion 4, the foam sheet 41 and the upper layer feeding element substrate 42 are laminated in this order from the lower layer. The upper layer feeding element substrate 42 is a substrate in which transmission patches 42b for transmitting polarization signals are arranged in a matrix. That is, a thin upper layer feeding board 42a having an insulating property such as a flexible substrate, a plurality of rectangular transmission patches 42b arranged on the upper layer feeding board 42a at the same positions as the receiving patch 26b, and the transmitting patch 42b are fed. It is provided with an upper layer feeding line 42c. The transmission patch 42b and the upper layer feeding line 42c are formed of the same conductive foil as the reception patch 26b and the like. Further, the upper layer feeding line 42c extends along a predetermined direction (direction orthogonal to the lower layer feeding line 26c) and is connected to a common feeding trunk line on the upper layer feeding board 42a.

Here, when the lower layer feeding element substrate 26 receives a polarization signal in a frequency band lower than that of the upper layer feeding element substrate 42, the size of the receiving patch 26b is set to be larger than that of the transmitting patch 42b.

In the fourth laminated portion 5, the foam sheet 51 and the upper layer slot plate 52 are laminated in order from the lower layer. The upper layer slot plate 52 is provided with a rectangular slot opening 52a at a position facing the transmission patch 42b.

In the fifth laminated portion 6, the foam sheet 61 and the inter-element feeding element substrate 62 are laminated in this order from the lower layer. The inter-element non-feeding element substrate 62 is a substrate in which inter-element non-feeding patches (inter-element non-feeding elements) 62b are arranged in a matrix, and is an elongated rectangular shape on a thin lower layer insulating substrate 62a having insulation properties such as a flexible substrate. A plurality of element-to-element non-feeding patches 62b of conductive foil are arranged in a shape.

As shown in FIG. 3, the inter-element non-feeding patch 62b is a non-feeding element extending in the excitation direction of the transmission patch 42b, that is, the feeding direction, and the plurality of inter-element non-feeding patches 62b are evenly distributed with the transmission patch 42b. It is arranged between the transmission patch 42b and the transmission patch 42b. Therefore, the arrangement spacing of the inter-element non-feeding patch 62b is the same as the arrangement spacing of the transmission patch 42b and the reception patch 26b, and the grating lobes generated between the upper layer feeding element substrate 42 and the inter-element non-feeding element substrate 62 have the same angle. Become a direction.

Further, the dimensions of the inter-element power feeding patch 62b and the inter-element non-feeding to the upper layer feeding element substrate 42 are canceled so that the grating lobe generated in the upper layer feeding element substrate 42 is canceled by the grating lobe generated in the inter-element non-feeding element substrate 62. The height of the element substrate 62 is set. That is, the amplitude of the grating lobe changes by adjusting the dimensions of the inter-element feeding patch 62b in the longitudinal direction (excitation direction of the transmission patch 42b). Further, the phase of the grating lobe is changed by adjusting the height position of the inter-element non-feeding element substrate 62 from the upper layer slot plate 52. Therefore, the longitudinal dimension and foaming of the inter-element non-feeding patch 62b so that the grating lobe having the same amplitude as that of the transmission patch 42b and having the opposite phase is generated in the inter-element non-feeding patch 62b. The thickness of the sheet 61 is adjusted and set.

In the sixth laminated portion 7, the foam sheet 71 and the upper layer non-feeding element substrate 72 are laminated in this order from the lower layer. The upper layer non-feeding element substrate 72 is a substrate in which non-feeding patches (non-feeding elements) 72b are arranged in a matrix, and a plurality of rectangular conductive foils are formed on a thin upper insulating substrate 72a having insulation properties such as a flexible substrate. The non-feeding patch 72b is arranged at the same position as the transmission patch 42b. The upper layer non-feeding element substrate 72 is installed at a height position that affects the directivity of the upper layer feeding element substrate 42 for transmission by the foam sheet 71 of the lower layer thereof, and the beam width of the upper layer feeding element substrate 42 is adjusted. Narrow it to improve frontal gain.

In the seventh laminated portion 8, the foam sheet 81, the inner cover 82, the foam sheet 83, and the upper cover 84 are laminated in this order from the lower layer. In this way, the reception patch 26b, the slot opening 32a, the transmission patch 42b, the slot opening 52a, and the non-feeding patch 72b are arranged at the same position, and the inter-element non-feeding patch 62b is arranged between them.

According to the present array antenna 1 having such a configuration, as described above, the inter-element non-feeding patch 62b is arranged between the transmission patch 42b and the transmission patch 42b, respectively, and the inter-element non-feeding patch 62b is arranged at intervals. Since the arrangement interval is the same as that of the transmission patch 42b, the grating lobes generated between the upper layer feeding element substrate 42 and the inter-element non-feeding element substrate 62 are in the same angular direction. Then, the dimensions of the inter-element non-feeding patch 62b and the inter-element non-feeding to the upper layer feeding element substrate 42 are canceled so that the grating lobe generated in the upper layer feeding element substrate 42 is canceled by the grating lobe generated in the inter-element non-feeding element substrate 62. Since the height of the element substrate 62 is set, it is possible to reduce the grating lobe and improve the frontal gain. Further, since the inter-element non-feeding element substrate 62 in which the inter-element non-feeding patch 62b is arranged is merely laminated, the thickness and weight are not significantly increased.

FIG. 4 shows the transmission directivity between the transmission / reception shared plane array antenna (hereinafter referred to as “contrast array antenna”) including the sixth laminated portion 7 but not the fifth laminated portion 6 and the present array antenna 1. It is a figure. This figure shows the transmission directivity centered on the Z axis (front) in the XZ plane where the observation plane angle φ = 0 °, and (a) shows the peripheral angular region (-10 degrees to +10 degrees) of the Z axis. ) Indicates the transmission directivity, and (b) indicates the transmission directivity in the wide angle range (-90 degrees to +90 degrees). From this figure, it can be confirmed that the grating lobe is reduced in the present array antenna 1 as compared with the contrast array antenna.

Further, FIG. 5 is a diagram showing the frontal gain and the aperture efficiency of the contrasting array antenna and the main array antenna 1, and FIG. 6 is a diagram showing the frontal gain with respect to the frequency of the contrasting array antenna and the main array antenna 1. .. Here, reference numeral Fc in FIG. 6 indicates the center frequency to be used, and FIG. 5 indicates the frontal gain and aperture efficiency at the center frequency Fc. From this figure, it can be confirmed that the present array antenna 1 has a higher frontal gain in the frequency band centered on the center frequency Fc than the contrast array antenna 1.

By the way, when a plurality of upper layer non-feeding element substrates 72 are laminated without providing the inter-element non-feeding element substrate 62, the transmission matching is greatly deviated, and the S parameter and the directivity are greatly changed. Further, depending on the size and height of the non-feeding patch 72b, other characteristics may be affected. On the other hand, since the array antenna 1 is provided with the inter-element feeding element substrate 62 as described above, it has an advantage that the grating lobe is reduced and the front gain is improved without affecting other characteristics. Has.

Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above-described embodiment, and even if there is a design change or the like within a range that does not deviate from the gist of the present invention. Included in the invention. For example, in the above-described embodiment, only one inter-element non-feeding element substrate 62 is provided, but a plurality of inter-element non-feeding element substrates 62 may be laminated. Further, the present invention may be applied to a circularly polarized light shared plane antenna in which circularly polarized light converters composed of a meander line polarizer or the like are stacked. Further, the shape of the conductive foil of the inter-element non-feeding patch 62b on the inter-element non-feeding element substrate 62 is not limited to a rectangle, and may be changed such as a rhombus.

1 Transmission / reception shared plane array antenna 26 Lower layer power feeding element board (reception board)
26b Reception patch (feeding element)
32 Lower layer slot board 42 Upper layer power feeding element board (transmission board)
42b transmission patch (feeding element)
52 Upper layer slot plate 62 Passive repeater board between elements 62b Passive patch between elements (passive element between elements)
72 Upper layer non-feeding element substrate 72b Passive patch (non-feeding element)

Claims (1)

A transmission board in which a plurality of feeding elements for transmitting a polarization signal are arranged in a matrix, and a reception in which a plurality of feeding elements for receiving a polarization signal are arranged at the same positions as the feeding elements of the transmission board. A transmission / reception shared plane array antenna comprising a substrate and having the reception substrate laminated under the transmission board to transmit and receive two polarization signals orthogonal to each other.
The inter-element non-feeding element, which is a non-feeding element extending in the excitation direction of the feeding element of the transmitting board, is arranged between the feeding element and the feeding element, respectively. Laminated on the upper side,
The dimensions of the inter-element non-feeding element and the height of the inter-element non-feeding element substrate with respect to the inter-element feeding substrate so that the grating lobe generated in the transmitting substrate is canceled by the grating lobe generated in the inter-element non-feeding element substrate. Is set,
A flat array antenna for both transmission and reception, which is characterized by this.

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