A broadband low active reflection patch phased array antenna

Abstract

The present invention discloses a broadband low active reflection patch phased array antenna, which combines back-to-back U-shaped metal strips and top-layer multiple patches with stacked square patches with square grooves for periodic arrangement, utilizes the effect of the back-to-back U-shaped metal strips on reducing the induced current of adjacent stacked patches, and the ability of the top-layer multiple patches to regulate the frequency corresponding to the lowest induced current, thereby realizing a broadband low active reflection patch phased array suitable for linear arrays, and has a small size, a simple structure and is easy to process.

Description

Technical Field

[0001] The invention relates to a microwave communication device, in particular to a patch phased array antenna. Background Art

[0002] Phased array antennas have the characteristics of high gain and wide coverage, and are widely used in radar and communication fields. However, during the scanning process, the phased array easily superimposes the signals of surrounding antenna units to form strong active reflection, which is not conducive to the stable operation of the system. It is usually necessary to reduce the active reflection through relevant technologies, and it is challenging to achieve low active reflection in a wide frequency range. Using patch antennas to achieve low active reflection phased arrays is conducive to improving the integration of phased array systems, facilitating processing, and reducing costs.

[0003] There are three main ways to implement low active reflection patch phased array antennas. The first is to load a transmission line network at the feeding level, use the network to couple with adjacent units to introduce additional signals, offset the reflected signals, and form a low active reflection patch phased array, which is applicable to both linear arrays and planar arrays, but the underlying feeding structure of the phased array is complex and difficult to integrate into the system, and the bandwidth is narrow. The second is to distribute coplanar periodic structures around the patch radiator to form a metasurface to suppress surface waves and reduce reflected signals, forming a low active reflection patch phased array, which can be used for linear arrays, but the metasurface needs to occupy a larger size and the overall bandwidth is narrow. The third is to load a parasitic structure composed of a ring and L-shaped structure between the diagonal patches to reduce the active reflection of the two-dimensional phased array, but this method is only applicable to planar arrays, not linear arrays, and more vias lead to a complex structure. Therefore, it is necessary to propose a broadband low active reflection patch phased array that is not only applicable to linear arrays, but also has a wide working bandwidth, a simple structure and a small size. Summary of the invention

[0004] Purpose of the invention: In view of the above-mentioned prior art, a broadband low active reflection patch phased array antenna is proposed to achieve broadband low active reflection and can work in a linear array. The structure is simple, easy to process, and small in size.

[0005] Technical solution: A broadband low-active reflection patch phased array antenna, comprising a top metal layer, a first substrate layer, an air layer, a second metal layer, a second substrate layer, a third metal layer, a third substrate layer, a metal ground layer, a fourth substrate layer, and a bottom metal layer arranged in sequence from top to bottom; the top metal layer comprises a top multi-patch periodically arranged in a linear direction, each top multi-patch is composed of a number of square small patches arranged at equal intervals in the linear direction; the second metal layer comprises metal square patches and back-to-back U-shaped metal strips periodically and alternately arranged in a linear direction, each The first metal square patch is provided with four square grooves arranged symmetrically in the center; the third metal layer includes the second metal square patch periodically arranged in the linear direction, and the center of each second metal square patch is provided with a second square groove; the metal ground layer includes an integral metal ground, and circular grooves are periodically arranged in the linear direction on the integral metal ground; the bottom metal layer includes vertical metal strips periodically arranged in the linear direction, and the end of each vertical metal strip is connected to a small metal disc; the geometric centers of each top multi-patch, the first metal square patch, and the second metal square patch are aligned one by one in sequence;

[0006] It also includes a plurality of feeding vias, each of which vertically passes through the circular groove and is used to connect the small metal disc and the second metal square patch.

[0007] Furthermore, in the top layer of multi-patches, the length of each small patch is 0.03-0.07λ0, and the spacing between adjacent small patches is 0.04-0.08λ0, where λ0 is the air wavelength of the center frequency.

[0008] Furthermore, the back-to-back U-shaped metal strips are composed of two U-shaped metal strips arranged back-to-back at intervals in a direction perpendicular to the linear direction, the vertical length of each U-shaped metal strip is 0.07~0.13λ0, the horizontal width is 0.02~0.06λ0, the side length of the metal square patch 1 is 0.2~0.24λ0, and λ0 is the air wavelength of the center frequency.

[0009] Furthermore, the side length of the second metal square patch is 0.21-0.25λ0, the side length of the second square slot is 0.04-0.06λ0, and λ0 is the air wavelength of the center frequency.

[0010] Furthermore, it also includes a plurality of plastic screws, which pass through all metal layers and substrate layers from both sides to fix the entire phased array and form an air layer between the first substrate layer and the second metal layer.

[0011] Furthermore, the center distance between adjacent top-layer multi-patches, the center distance between adjacent metal square patches one, and the center distance between adjacent metal square patches two are all 0.49λ0, where λ0 is the air wavelength of the center frequency.

[0012] Furthermore, the frequency corresponding to the lowest induced current is controlled by adjusting the length and spacing of each small patch in the top layer of multi-patches.

[0013] Furthermore, the air layer height is 0.13λ0.

[0014] Beneficial effects: Existing low active reflection patch phased arrays cannot take into account linear array, broadband operation, low structural complexity and small size. The present invention combines back-to-back U-shaped metal strips and top-layer multi-patch with stacked square patches with square grooves for periodic arrangement, and utilizes the back-to-back U-shaped metal strips to reduce the induced current of adjacent stacked patches, and the top-layer multi-patch's ability to regulate the frequency corresponding to the lowest induced current, to achieve a broadband low active reflection patch phased array suitable for linear arrays, and with small size, simple structure and easy processing.

[0015] Specifically, the back-to-back U-shaped metal strips and the metal square patch one are periodically alternately distributed, and can present symmetrical unidirectional currents when working. They can reduce the induced current on the adjacent metal square patch two on the E surface within a wide frequency range, and form a frequency point with the lowest induced current within the frequency band, ensuring that the induced current in the entire frequency band is reduced to a certain extent, thereby realizing a broadband low active reflection linear patch phased array.

[0016] The top-layer multi-patch structure is periodically arranged directly above the metal square patch. By adjusting the length and spacing of each small patch in the top-layer multi-patch, the control capability of the frequency corresponding to the minimum induced current can be enhanced, thereby further reducing the active reflection within the overall frequency band of the phased array, and realizing a broadband, low active reflection linear horizontally polarized patch phased array. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the layer structure of broadband low active reflection patch phased array structure;

[0018] Figure 2 Schematic diagram of the top metal layer structure;

[0019] Figure 3 is a schematic diagram of the structure of the second metal layer;

[0020] Figure 4 is a schematic diagram of the structure of the third metal layer;

[0021] Figure 5 It is a schematic diagram of the metal stratum structure;

[0022] Figure 6 is a schematic diagram of the bottom metal layer structure;

[0023] Figure 71 is an active reflection coefficient curve of different unit ports of the phased array in the embodiment when scanning, wherein (a) is an active reflection coefficient curve of an edge unit, and (b) is an active reflection coefficient curve of a center unit;

[0024] Figure 8 2 are horizontal polarization scanning patterns of the phased array at 3.3 GHz and 3.7 GHz in the embodiment, where (a) is horizontal polarization 3.3 GHz and (b) is horizontal polarization 3.7 GHz. DETAILED DESCRIPTION

[0025] The present invention will be further explained below in conjunction with the accompanying drawings.

[0026] like Figure 1 As shown, a broadband low active reflection patch phased array antenna includes a top metal layer 1, a first substrate layer 2, a second metal layer 3, a second substrate layer 4, a third metal layer 5, a third substrate layer 6, a metal ground layer 7, a fourth substrate layer 8, and a bottom metal layer 9, which are arranged in sequence from top to bottom, and also include a feed via 10 and a plastic screw 11.

[0027] like Figure 2 As shown, the top metal layer 1 is composed of top-layer multi-patch 101 periodically arranged along the linear direction. The top-layer multi-patch 101 is composed of a number of square small patches arranged at equal intervals along the linear direction, each small patch is between 0.03 and 0.07 λ0 long, and the spacing between adjacent small patches is between 0.04 and 0.08λ0, where λ0 is the air wavelength of the center frequency.

[0028] like Figure 3 As shown, the second metal layer 3 is composed of metal square patch 1 302 and back-to-back U-shaped metal strips 301 periodically arranged alternately along the linear direction. Among them, the metal square patch 1 302 has four square grooves 1 303 arranged symmetrically with respect to the center, the side length of the metal square patch 1 302 is between 0.2 and 0.24λ0, and the side length of the square groove 1 303 is between 0.01 and 0.02λ0. The back-to-back U-shaped metal strips 301 are composed of two U-shaped metal strips arranged back-to-back in a vertical direction to the above linear direction, the vertical length of each U-shaped metal strip is between 0.07 and 0.13λ0, the horizontal width is between 0.02 and 0.06λ0, and the spacing between the two U-shaped metal strips is 0.02λ0. The geometric center of the metal square patch 1 302 is aligned with the geometric center of the top multi-patch 101.

[0029] like Figure 4As shown, the third metal layer 5 is composed of metal square patches 2 501 arranged periodically along the linear direction. A square groove 2 502 is etched in the center of the metal square patch 2 501, the side length of the metal square patch 2 501 is between 0.21 and 0.25λ0, and the side length of the square groove 2 502 is between 0.04 and 0.06λ0. The geometric center of the metal square patch 2 501 is aligned with that of the metal square patch 1 302.

[0030] like Figure 5 As shown, the metal layer 7 includes an overall metal layer 702 , and circular grooves 701 arranged periodically are etched along a linear direction on the overall metal layer 702 , and a plurality of air holes 703 arranged periodically are etched on both sides of the overall metal layer 702 .

[0031] like Figure 6 As shown, the bottom metal layer 9 is composed of vertical metal strips 901 arranged periodically along a linear direction and small metal disks 902 at the ends of the strips.

[0032] Each feed via 10 vertically passes through the circular groove 701, and is used to connect the metal small disc 902 and the metal square patch 2 501 of the third metal layer 5. The plastic screw 11 is located at the circular groove 703 on both sides of the metal layer 7, and passes through all metal layers and substrate layers to fix the entire phased array. The first substrate layer 2 and the second metal layer 3 are separated, that is, there is an air layer between the two layers with a height of 0.13λ0. The vertical metal strip 901, the metal layer 7 and the fourth substrate layer 8 constitute the microstrip feed line of the phased array.

[0033] In the above structure, the units are arranged periodically along the linear direction, that is, the center distance between adjacent top-layer multi-patches 101, the center distance between adjacent metal square patches 1 302, and the center distance between adjacent metal square patches 2 501 are all 0.49λ0.

[0034] In the present invention, the input signal of each microstrip feeder is pre-configured in phase according to the phase control theory, and under the overall action of the top multi-patch 101, the metal square patch 1 302, the back-to-back U-shaped strip 301, and the metal square patch 2 501, a broadband low active reflection designated direction beam is realized. In this process, the phased array works in a horizontal polarization state. The periodically arranged back-to-back U-shaped metal strips 301 present symmetrical unidirectional currents, which can reduce the EThe induced current on the adjacent metal square patch 2 501 is adjusted, and a frequency point with the lowest induced current is formed in the frequency band, so as to ensure that the induced current in the entire frequency band is reduced to a certain extent, thereby realizing a broadband low active reflection phased array. However, the back-to-back U-shaped metal strips 301 have limited control capabilities for the frequency corresponding to the lowest induced current, so that the induced current in the high-frequency part of the frequency band is limited. Therefore, the top-layer multi-patch 101 is mainly used to further enhance the control capability of the frequency corresponding to the lowest induced current. By adjusting the length and spacing of each small patch in the top-layer multi-patch 101, the frequency corresponding to the lowest induced current can be further controlled, thereby further reducing the active reflection in the overall frequency band of the phased array, and realizing a broadband low active reflection horizontal polarization patch phased array.

[0035] Compared with the best existing technology, the advantages of the low active reflection patch phased array proposed by the present invention are that it can take into account broadband, small-size linear array operation and simple structure and easy processing. The substrate used in this embodiment is RO4003C, with a plane size of 0.7λ0×3.9λ0, and its phased array structure is as follows Figures 1 to 6 As shown in Figure 1, it is a 1×8 linear patch phased array. The active reflection parameters of the simulated edge unit port and center unit port are as follows: Figure 7 As shown. Figure 7 It can be seen that when the phased array works under direct radiation conditions, the -10 dB active reflection coefficient bandwidth of the edge unit can cover 3.15-3.71 GHz, and the -10 dB active reflection coefficient bandwidth of the center unit can cover 3.16-3.72 GHz; when scanning 15°, the -10 dB active reflection coefficient bandwidth of the edge unit can cover 3.17-3.71 GHz, and the -10 dB active reflection coefficient bandwidth of the center unit can cover 3.16-3.72 GHz; when scanning 30°, the -10 dB active reflection coefficient bandwidth of the edge unit can cover 3.18-3.72 GHz, and the -10 dB active reflection coefficient bandwidth of the center unit can cover 3.2-3.72 GHz; when scanning 45°, the -10 dB active reflection coefficient bandwidth of the edge unit can cover 3.2-3.72 GHz, and the -10 dB active reflection coefficient bandwidth of the center unit can cover 3.28-3.73 GHz. Therefore, within the ±45° scanning range, the -10 dB active reflection coefficient bandwidth reaches 12.8% and can effectively cover 3.3-3.7 GHz.

[0036] Figure 8 The simulated scanning patterns of this case at 3.3 GHz and 3.7 GHz are shown. Figure 8 As can be seen from (a) of Figure 1, at 3.3 GHz, the beam gain within the ±45° scanning range is between 12.5 and 14.3 dBi, and the gain fluctuation is 1.8 dB. Figure 8 As can be seen in (b), at 3.7 GHz, the beam gain within the ±45° scanning range is between 12.3 and 14.5 dBi, and the gain fluctuation is 2.2 dB. Therefore, the phased array can achieve a ±45° scanning range within the matching frequency band, and the scanning gain fluctuation is less than 3.0 dB.

[0037] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A broadband low active reflection patch phased array antenna, characterized in that: The invention comprises a top metal layer (1), a first substrate layer (2), an air layer, a second metal layer (3), a second substrate layer (4), a third metal layer (5), a third substrate layer (6), a metal ground layer (7), a fourth substrate layer (8), and a bottom metal layer (9) which are arranged in sequence from top to bottom; The top metal layer (1) comprises top-layer multi-patch (101) periodically arranged along a linear direction, and each top-layer multi-patch (101) is composed of a plurality of square small patches arranged at equal intervals along the linear direction; The second metal layer (3) comprises metal square patches (302) and back-to-back U-shaped metal strips (301) periodically and alternately arranged along a linear direction, and each metal square patch (302) is provided with four square grooves (303) arranged symmetrically with respect to the center; The third metal layer (5) comprises metal square patches (501) arranged periodically along a linear direction, and each metal square patch (501) is provided with a square groove (502) at the center thereof; The metal layer (7) includes an integral metal layer (702), on which circular grooves (701) are periodically arranged along a linear direction; The bottom metal layer (9) comprises vertical metal strips (901) periodically arranged along a linear direction, and a small metal disc (902) is connected to the end of each vertical metal strip (901); The geometric centers of the top-layer multi-patch (101), the metal square patch one (302), and the metal square patch two (501) are aligned one by one; It also includes a plurality of feeding vias (10), each feeding via (10) vertically passing through the circular slot (701) and being used to connect the small metal disc (902) and the second metal square patch (501).

2. The broadband low active reflection patch phased array antenna according to claim 1, characterized in that: In the top layer of multi-patch (101), the length of each small patch is 0.03-0.07 λ0, the spacing between adjacent small patches is 0.04-0.08λ0, and λ0 is the air wavelength of the center frequency.

3. The broadband low active reflection patch phased array antenna according to claim 1, characterized in that: The back-to-back U-shaped metal strips (301) are composed of two U-shaped metal strips arranged back-to-back in a direction perpendicular to the linear direction, each U-shaped metal strip has a vertical length of 0.07-0.13λ0 and a horizontal width of 0.02-0.06λ0, and the side length of the metal square patch 1 (302) is 0.2-0.24λ0, where λ0 is the air wavelength of the center frequency.

4. The broadband low active reflection patch phased array antenna according to claim 1, characterized in that: The side length of the second metal square patch (501) is 0.21-0.25λ0, and the side length of the second square slot (502) is 0.04-0.06λ0, where λ0 is the air wavelength of the center frequency.

5. The broadband low active reflection patch phased array antenna according to claim 1, characterized in that: It also includes a plurality of plastic screws (11), which pass through all metal layers and substrate layers from both sides, are used to fix the entire phased array, and form an air layer between the first substrate layer (2) and the second metal layer (3).

6. The broadband low active reflection patch phased array antenna according to any one of claims 1 to 5, characterized in that: The center distance between adjacent top-layer multi-patches (101), the center distance between adjacent metal square patches one (302), and the center distance between adjacent metal square patches two (501) are all 0.49λ0, where λ0 is the air wavelength of the center frequency.

7. The broadband low active reflection patch phased array antenna according to any one of claims 1 to 5, characterized in that: The frequency corresponding to the lowest induced current is regulated by adjusting the length and spacing of each small patch in the top multi-patch (101).

8. The broadband low active reflection patch phased array antenna according to claim 6, characterized in that: The air layer height is 0.13λ0.

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