High-isolation dual-polarized broadband antenna array

Abstract

The invention discloses a high-isolation dual-polarization broadband antenna array which comprises a plurality of array elements and a pi-shaped decoupling structure. The antenna is composed of a plurality of array elements with EBG structures, the array elements are arranged in a triangular grid mode, each array element comprises a radiation patch etched on the top of a microstrip dielectric plate and a metal substrate, a metal enclosure frame is arranged between the metal substrate and the microstrip dielectric plate, the top of the metal enclosure frame is provided with a periodic square sawtooth structure, and the periodic square sawtooth structure is arranged on the top of the metal enclosure frame. A gap is reserved at the top of the metal enclosure frame close to the microstrip dielectric plate; according to the dual-polarization bandwidth antenna array, the Pi-shaped decoupling structures are aperiodically arranged between every two adjacent array elements, that is, the EBG structures in the array elements are combined with the Pi-shaped decoupling structures in the array, so that the decoupling effect is improved, high isolation of the dual-polarization bandwidth antenna array is achieved, and the decoupling structures are simpler.

Description

Technical Field

[0001] The invention relates to the technical field of broadband microwave antenna arrays, and in particular to a high-isolation dual-polarization broadband antenna array. Background Art

[0002] Dual-polarized antenna arrays are widely used in various wireless communication systems. The port isolation of the antenna array depends on the port isolation of each array element. However, with the development of equipment miniaturization and functional diversification, the antenna array is getting smaller and smaller, the array element spacing is getting closer, and the mutual coupling between array elements is getting greater and greater, which seriously affects the isolation between adjacent array elements.

[0003] At present, unit optimization and array decoupling can improve the port isolation and polarization isolation of antenna arrays. Although the unit optimization method can achieve good unit performance, the number of radiating units in the antenna array is increasing, and it cannot directly improve the isolation degradation caused by array mutual coupling; the array decoupling method directly uses decoupling structures such as array antenna decoupling surface (ADS) and electromagnetic band gap (EBG) in the antenna array to reduce the correlation between array elements and reduce the mutual interference between radiating units. Although it can reduce the isolation degradation caused by coupling between arrays without affecting the form of array elements, it is necessary to load a complex decoupling structure on the antenna array. In addition, when decoupling a wide frequency band, a multi-layer array antenna decoupling surface is required. The multi-layer decoupling surfaces will affect each other, resulting in poor decoupling effect, thereby reducing the isolation of the antenna array. Summary of the invention

[0004] The purpose of the present invention is to design a high-isolation dual-polarization broadband antenna array in order to solve the above problem.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions: High-isolation dual-polarization broadband antenna array, including: A plurality of array elements, wherein the plurality of array elements are arranged in a triangular grid, each of the array elements comprises a radiation patch and a metal substrate etched on the top of a microstrip dielectric plate, a metal frame is provided between the metal substrate and the microstrip dielectric plate, a periodic square sawtooth structure is provided on the top of the metal frame, and a gap is left near the top of the metal frame near the microstrip dielectric plate; A π-shaped decoupling structure is arranged non-periodically between each adjacent array element.

[0006] The beneficial effects of the present invention are: The high-isolation dual-polarization broadband antenna array is composed of multiple array elements with built-in EBG structures, and the multiple array elements are arranged in a triangular grid. Each array element includes a radiation patch and a metal substrate etched on the top of a microstrip dielectric plate. A metal frame is arranged between the metal substrate and the microstrip dielectric plate. The top of the metal frame has a periodic square sawtooth structure, and a gap is left near the top of the metal frame near the microstrip dielectric plate. A π-shaped decoupling structure is non-periodically arranged between each adjacent array element, that is, the EBG structure in the array element is combined with the π-shaped decoupling structure in the array to improve the decoupling effect, thereby achieving high isolation of the dual-polarization broadband antenna array, and the decoupling structure is simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 The overall structure diagram of the high-isolation dual-polarization broadband antenna array of the present invention; Figure 2 A triangular grid layout diagram of a high-isolation dual-polarization broadband antenna array of the present invention; Figure 3 It is a π-shaped decoupling structure diagram of the high-isolation dual-polarization broadband antenna array of the present invention; Figure 4 It is a structural diagram of array element decomposition of the dual-polarization broadband antenna array with high isolation of the present invention; Figure 5 The structure diagram of the array element of the high-isolation dual-polarization broadband antenna array of the present invention; Figure 6 This is a comparison diagram of the isolation before and after the π-shaped decoupling structure is loaded in the high-isolation dual-polarization broadband antenna array of the present invention; Figure 7 This is a diagram of S-parameter simulation results of an element of a high-isolation dual-polarization broadband antenna array of the present invention; Figure 8 A normal gain result diagram of an array element of a high-isolation dual-polarization broadband antenna array of the present invention; In the figure: 1-metal substrate, 2-metal frame, 3-dielectric clip, 4-radiation patch, 5-short-circuit stud, 6-fixing screw, 7-annular seam, 8-gap, 9-tuning branch, 10-π-shaped decoupling structure. DETAILED DESCRIPTION

[0008] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0009] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0010] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0011] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0012] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0013] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0014] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0015] like Figure 1-8 As shown, a high-isolation dual-polarization broadband antenna array includes: A plurality of array elements, wherein the plurality of array elements are arranged in a triangular grid, each of the array elements comprises a radiation patch 4 etched on the top of a microstrip dielectric plate and a metal substrate 1, a metal frame 2 is provided between the metal substrate 1 and the microstrip dielectric plate, a periodic square sawtooth structure is provided on the top of the metal frame 2, and a gap 8 is left near the top of the microstrip dielectric plate; The π-shaped decoupling structure 10 is arranged non-periodically between each adjacent array element.

[0016] In this embodiment, the size of the microstrip dielectric plate is l =0.4λ, the height between the top and bottom of the microstrip dielectric plate is h=0.1λ, a gap 8 is left at the top of the metal frame 2 near the microstrip dielectric plate, and the size of the gap 8 is 0.02λ; there is a periodic square sawtooth structure on the top of the metal frame 2, and the size of the periodic square sawtooth structure can be adjusted according to the specific working frequency. Therefore, the gap 8 and the periodic square sawtooth structure jointly form an EBG structure.

[0017] In this embodiment, the dual-polarized broadband array antenna adopts a triangular grid array. Compared with a rectangular grid array, the triangular grid array can provide a larger spacing and space between array elements for placing a decoupling structure without the appearance of grating lobes by staggered arrangement of array elements. In the triangular grid layout, the left-right spacing of each array element is 0.5λ, and the top-bottom spacing of each array element is 0.8λ.

[0018] In this embodiment, in a triangular grid array composed of array elements, a non-periodically arranged π-shaped decoupling structure 10 whose width and height are determined by the working wavelength is added between each adjacent array element. The port isolation between adjacent array elements can be changed by adjusting the position of the upper and lower adjacent array elements of the π-shaped decoupling structure 10. After the position of the π-shaped decoupling structure 10 is determined, the π-shaped decoupling structure 10 is fixed to the metal substrate 1 of the array with screws or conductive adhesive to ensure that the π-shaped decoupling structure 10 and the metal substrate 1 have good grounding performance.

[0019] Furthermore, the top crossbeam of the π-shaped decoupling structure 10 is parallel to the gap 8 at the top of the metal enclosure 2; the π-shaped decoupling structure 10 can be bent by an aluminum or copper part of a certain thickness, and the bending angle is 90°. The length of the π-shaped decoupling structure 10 is composed of a straight crossbeam plus the bent parts on the left and right sides, and the length is 0.45λ; the height is located at the gap 8 of the square sawtooth of the unit metal enclosure 2, which is 0.08λ. Since the gap 8 of the array element and the periodic square sawtooth structure jointly form an EBG structure, the mutual coupling at this height is the strongest. On the adjacent array element spacing, by adjusting the upper and lower positions of the π-shaped decoupling structure 10 in the array element spacing, the mutual coupling relationship between adjacent array elements will be affected. Selecting a suitable position can improve the isolation of adjacent units.

[0020] In this embodiment, the high-isolation dual-polarization broadband antenna array is composed of a plurality of array elements with built-in EBG structures, and the plurality of array elements are arranged in a triangular grid. Each array element includes a radiation patch 4 etched on the top of a microstrip dielectric plate and a metal substrate 1. A metal frame 2 is provided between the metal substrate 1 and the microstrip dielectric plate. A periodic square sawtooth structure is provided on the top of the metal frame 2, and a gap 8 is left near the top of the microstrip dielectric plate. A π-shaped decoupling structure 10 is non-periodically arranged between each adjacent array element, that is, the EBG structure in the array element is combined with the π-shaped decoupling structure 10 in the array to improve the decoupling effect, thereby achieving high isolation of the dual-polarization broadband antenna array.

[0021] Figure 6 The figure is a comparison diagram of the isolation of two adjacent array elements in the high-isolation dual-polarization broadband antenna array of the present invention, wherein the dotted line is the adjacent port isolation curve without the π-shaped decoupling structure, and the solid line is the adjacent port isolation curve with the π-shaped decoupling structure. It can be understood that the array element isolation is improved from the original -20dB to -30dB, and the optimal center frequency is even close to -45dB. It can be seen that the present invention combines the EBG structure in the array element with the π-shaped decoupling structure 10 in the array, so that the isolation characteristics are further improved.

[0022] In one embodiment, a short-circuit stud 5 is provided at the center of the microstrip dielectric plate, and a fixing screw 6 is provided in the middle of the metal frame 2 , and the fixing screw 6 is used to fix the radiation patch 4 and the short-circuit stud 5 .

[0023] In this embodiment, the fixing screws 6 can be implemented by metal screws to fasten the microstrip dielectric board and the metal surrounding frame 2, thereby improving the antenna port isolation.

[0024] In one embodiment, two spaced-apart parallel feeding holes symmetrical to the short-circuit stud 5 are provided at the ±45° diagonal lines on the radiation patch 4 , and an annular seam 7 concentric with the feeding hole is provided on the outer circle of the feeding hole.

[0025] In this embodiment, two spaced-apart parallel feeding holes with symmetrical short-circuit studs 5 are formed on the ±45° diagonal lines on the radiation patch 4, and an annular seam 7 concentric with the feeding hole is formed on the outer circle of the feeding hole. The feeding needle passing through the metal base plate passes through the annular seam 7 feeding hole and is welded to the radiation patch 4 to form linear polarization feeding, thereby capacitively loading the antenna to improve the impedance bandwidth of the antenna. Figure 7 are the S parameters of the two feeding ports of dual polarization, Figure 8It is a dual-polarization gain pattern within the working frequency band, including the 1-port reflection coefficient S11 corresponding to +45° polarization, the 2-port reflection coefficient S22 corresponding to -45° polarization, and the isolation S21 between the two polarizations. The reflection coefficients S11 and S22 of the array element are both less than -10dB within the frequency range of 2400MHz~2800MHz, the isolation S21 is less than -22dB, and the normal gain is greater than 6dBi within the full frequency band.

[0026] In one embodiment, the high-isolation dual-polarization broadband antenna array includes four dielectric buckles 3, and four walls at the top of the metal frame 2 are provided with card slots, and each of the dielectric buckles 3 matches the corresponding card slot.

[0027] In this embodiment, the dielectric buckle 3 can be replaced by non-metallic materials such as plastic, nylon or low-loss materials to support the microstrip dielectric board and ensure that the size of the gap 8 between the microstrip dielectric board and the top of the metal frame 2 is maintained at 0.02λ.

[0028] In one embodiment, tuning branches 9 are provided at the central symmetric positions of the edges of the radiation patch 4 .

[0029] Furthermore, the tuning branch 9 is T-shaped.

[0030] Since there may be processing errors in different batches of array elements, in this embodiment, T-shaped tuning branches 9 are added to the edges of the radiation patch 4 symmetrically about the center. The impedance matching characteristics of the array element can be changed by cutting the T-shaped tuning branches 9 to increase the means of array element debugging. Specifically, cutting off part or all of the pattern of the debugging branches can shift the impedance of the array element toward high frequency, and after the T-shaped tuning branches 9 are completed with solder, the impedance characteristics of the array element can be shifted toward low frequency.

[0031] 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 technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-isolation dual-polarization broadband antenna array, characterized in that: The high-isolation dual-polarization broadband antenna array comprises: A plurality of array elements, wherein the plurality of array elements are arranged in a triangular grid, each of the array elements comprises a radiation patch and a metal substrate etched on the top of a microstrip dielectric plate, a metal frame is provided between the metal substrate and the microstrip dielectric plate, a periodic square sawtooth structure is provided on the top of the metal frame, and a gap is left near the top of the metal frame near the microstrip dielectric plate; A π-shaped decoupling structure is arranged non-periodically between each adjacent array element.

2. The high-isolation dual-polarization broadband antenna array according to claim 1, characterized in that: The top crossbeam of the π-shaped decoupling structure is parallel to the gap at the top of the metal frame.

3. The high-isolation dual-polarization broadband antenna array according to claim 1, characterized in that: A short-circuit stud is arranged at the center of the microstrip dielectric plate, and a fixing screw is arranged in the middle of the metal surrounding frame, and the fixing screw is used to fix the radiation patch and the short-circuit stud.

4. The high-isolation dual-polarization broadband antenna array according to claim 3, characterized in that: Two spaced and parallel feeding holes symmetrical to the short-circuit studs are arranged at the ±45° diagonals on the radiation patch, and an annular seam concentric with the feeding hole is arranged on the outer circle of the feeding hole.

5. The high-isolation dual-polarization broadband antenna array according to claim 4, characterized in that: The high-isolation dual-polarization broadband antenna array includes four dielectric buckles, and four walls on the top of the metal frame are provided with card slots, and each of the dielectric buckles matches the corresponding card slot.

6. The high-isolation dual-polarization broadband antenna array according to claim 1, characterized in that: Tuning branches are arranged at the central symmetric positions of the edges around the radiation patch.

7. The high-isolation dual-polarization broadband antenna array according to claim 6, characterized in that: The tuning branch is T-shaped.

8. The high-isolation dual-polarization broadband antenna array according to claim 1, characterized in that: The size of the microstrip dielectric plate is 0.4λ; In the triangular grid, the left-right spacing of each array element is 0.5λ, and the top-bottom spacing of each array element is 0.8λ.

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