Broadband dual-polarization patch antenna

Abstract

The broadband dual-polarization patch antenna comprises a radiation layer, a dual-polarization feed layer and a bottom plate which are sequentially arranged from top to bottom, the radiation layer comprises a first metal patch layer and a first dielectric layer; the first metal patch layer is arranged on the upper surface of the first dielectric layer; the dual-polarization feed layer comprises a second metal patch layer, a second dielectric layer, a third metal patch layer, a third dielectric layer, a fourth metal patch layer, a fourth dielectric layer, a fifth metal patch layer and a metalized through hole which are arranged from top to bottom; the second metal patch layer is provided with a coupling gap, the third metal patch layer is provided with a vertical polarization feed, the fourth metal patch layer is provided with a horizontal polarization feed, and the fifth metal patch layer is a metal ground plane; the bottom plate serves as a fixed mounting plate and a reflecting plate. The invention has the advantages of simple and compact structure, low cost, high isolation, easy array formation and the like.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of radar antennas, and in particular to a broadband dual-polarization patch antenna. Background Art

[0002] Dual-polarized antennas are widely used in the fields of communication and radar because they can transmit and receive two orthogonal electromagnetic waves in space, which can improve spectrum utilization for communication systems and provide radar systems with more information about targets. In addition, patch antennas are also frequently used in dual-polarized antenna design because of their low cost, low profile, and easy integration.

[0003] Some practitioners have proposed some technical solutions around dual-polarized patch antennas. For example, Chinese patent CN115051163A proposes a small dual-polarized patch antenna and wireless communication system working in the S band. This technical solution is to realize the miniaturization design of the antenna by loading short-circuit pins and radiating patch slots, but the antenna impedance bandwidth is only 2.6%, which cannot meet the application in broadband systems. Another practitioner proposed Chinese patent CN114696099A, whose technical solution is a broadband dual-polarized microstrip antenna suitable for dual-mode operation in the microwave and millimeter wave frequency bands. The broadband design is achieved through cross-slot coupling feeding and dual-mode resonant patches, but the antenna unit size is larger than λ. H / 2(λ H The antenna has a 1 / 2 free space wavelength of the highest operating frequency), which cannot meet the needs of some MIMO array and phased array applications, and the antenna has a blind hole design, which increases the difficulty and cost of processing. Another practitioner proposed the Chinese patent CN110635232A. This technical solution is a dual-polarized microstrip antenna unit with wide-angle and broadband scanning capability that works in the S band. It realizes the broadband design of the antenna through cross-slot coupling and double-layer radiation patches, but the antenna bandwidth is still less than 20%, which limits the application of the antenna in wider bandwidth systems. In addition, the antenna uses a large number of PCB layers, which increases the processing and assembly costs.

[0004] In the existing technology, dual-polarized patch antennas mainly have two forms: microstrip or coaxial direct feeding and coupled feeding. Direct feeding requires fewer PCB layers, which makes it easy to miniaturize the antenna, but the antenna bandwidth is narrow, and because there is no physical separation between the feed lines, the port isolation of the two polarizations is often low, and the radiation of the feed itself will also lead to an increase in cross-polarization; although adding coplanar parasitic patches can expand the bandwidth, it will increase the area of ​​the antenna unit. By introducing new resonance points through coupled feeding or multi-layer radiating patches, wider bandwidth impedance matching can be achieved, but the number of PCB layers will increase, and it is also easy to introduce blind hole design, resulting in increased processing costs.

[0005] From the above, it can be seen that if one wants to simultaneously achieve miniaturization, broadband, and high isolation of dual-polarized patch antennas, this is still a huge challenge technically. Summary of the invention

[0006] The technical problem to be solved by the present invention is: in view of the technical problems existing in the prior art, the present invention provides a broadband dual-polarization patch antenna with simple and compact structure, low cost, high isolation and easy array formation.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: A broadband dual-polarization patch antenna, comprising: A radiation layer, a dual-polarization feeding layer and a bottom plate are arranged in sequence from top to bottom; The radiation layer includes a first metal patch layer and a first dielectric layer; the first metal patch layer is arranged on the upper surface of the first dielectric layer; The dual-polarization feed layer comprises a second metal patch layer, a second dielectric layer, a third metal patch layer, a third dielectric layer, a fourth metal patch layer, a fourth dielectric layer, a fifth metal patch layer and a metallized through hole arranged from top to bottom; a coupling gap is arranged on the second metal patch layer, a vertical polarization feed is arranged on the third metal patch layer, a horizontal polarization feed is arranged on the fourth metal patch layer, and the fifth metal patch layer is a metal ground plane; The bottom plate serves as a fixed mounting plate and a reflecting plate.

[0008] As a further improvement of the present invention: the first metal patch layer is used as a radiation patch, and orthogonal cross slots are loaded on the radiation patch to increase two orthogonally polarized current paths.

[0009] As a further improvement of the present invention: the first metal patch layer is in a square, rectangular, circular or polygonal shape.

[0010] As a further improvement of the present invention: an orthogonal coupling gap is provided on the second metal patch layer, the shape of the orthogonal coupling gap is composed of a square opening loaded with two pairs of inwardly protruding conical metal ridges (211, 212), and the square opening is surrounded by metallized through holes to form a square resonant cavity.

[0011] As a further improvement of the present invention: the third metal patch layer is provided with a vertical polarization feed, and the fourth metal patch layer is provided with a horizontal polarization feed, and the vertical polarization feed and the horizontal polarization feed are both composed of a strip line loaded with an open circuit fan-shaped junction, and input impedance matching is achieved by adjusting the open circuit branch length and the fan-shaped junction size of the two feeds.

[0012] As a further improvement of the present invention: the inputs of the vertical polarization feed and the horizontal polarization feed are both excited by coaxial radio frequency connectors.

[0013] As a further improvement of the present invention: a plurality of screw fixing holes are opened at the corners of the first dielectric layer, and the first dielectric layer is supported and fixed by nylon screws and nylon columns.

[0014] As a further improvement of the present invention: the support height of the nylon column is consistent with the distance from the lower surface of the first dielectric layer to the upper surface of the second metal patch layer, and broadband electromagnetic coupling between the radiation layer and the dual-polarization feeding layer is achieved by adjusting the support height.

[0015] As a further improvement of the present invention: the bottom plate is a metal bottom plate, and the upper surface of the bottom plate is bonded to the lower surface of the fifth metal patch layer.

[0016] As a further improvement of the present invention: the bottom plate is provided with screw fixing holes and coaxial RF connector avoidance holes.

[0017] Compared with the prior art, the advantages of the present invention are: The broadband dual-polarized patch antenna of the present invention has the advantages of low cost, low profile, high isolation and easy array formation. The present invention is based on the slot-coupled patch antenna technology and uses a 4-layer laminate to design a compact broadband orthogonal polarization feeding network, avoiding the quarter-wavelength reflector height required for a traditional planar dipole antenna; only one layer of radiation patch is used above the feeding layer, and a "cross" gap is loaded on the radiation patch to further reduce the patch size; broadband electromagnetic coupling between the radiation layer and the dual-polarized feeding layer is achieved through an air lamination design, blind holes are avoided in the entire design, and the number of PCB layers is relatively small, so that the antenna obtains broadband performance and high isolation characteristics with a low profile and small size, and has the advantages of low cost, easy assembly, and applicability to large-angle scanning arrays. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structural principle of the present invention in a specific embodiment.

[0019] Figure 2 It is a schematic diagram of the main structural principle of the present invention in a specific embodiment.

[0020] Figure 3 It is a schematic diagram of the top view structure of the radiation layer in a specific embodiment of the present invention.

[0021] Figure 4 It is a schematic diagram of the top view structure of the dual-polarization feeding layer in a specific embodiment of the present invention.

[0022] Figure 5 It is a schematic diagram of the top structure of the bottom plate in a specific embodiment of the present invention.

[0023] Figure 6 It is a schematic diagram of S parameters of each port of the antenna in a specific embodiment of the present invention.

[0024] Figure 7 It is a schematic diagram of the vertical polarization radiation pattern of the antenna in a specific embodiment of the present invention.

[0025] Figure 8 It is a schematic diagram of the horizontal polarization radiation pattern of the antenna in a specific embodiment of the present invention.

[0026] Fig. 9 It is a schematic diagram of the peak gain of the antenna in a specific embodiment of the present invention.

[0027] Fig.10 It is a top view of a one-dimensional scanning array in a specific embodiment of the present invention.

[0028] Fig.11 It is the vertical polarization azimuth plane scanning pattern in a specific embodiment of the present invention.

[0029] Fig.12 In a specific embodiment of the invention, the azimuth plane scanning pattern is horizontally polarized. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0033] In this application, unless otherwise clearly specified and limited, the terms "assemble", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it 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, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0034] like Figures 1 to 5 The present invention discloses a broadband dual-polarization patch antenna for S-band applications, comprising a radiation layer 1, a dual-polarization feeding layer 2 and a base plate 3; the radiation layer 1, the dual-polarization feeding layer 2 and the base plate 3 are arranged in sequence from top to bottom.

[0035] The radiation layer 1 includes a first metal patch layer 11 and a first dielectric layer 12; the first metal patch layer 11 is arranged on the upper surface of the first dielectric layer 12; four screw fixing holes are opened at the four corners of the first dielectric layer 12, and it is supported and fixed by nylon screws 13 and nylon columns 14.

[0036] The dual-polarization feed layer 2 includes a multi-layer PCB laminate, which includes, from top to bottom: a second metal patch layer 21, a second dielectric layer 22, a third metal patch layer 23, a third dielectric layer 24, a fourth metal patch layer 25, a fourth dielectric layer 26, a fifth metal patch layer 27, and a metallized through hole 28. The second metal patch layer 21 is provided with a coupling gap, the third metal patch layer 23 is provided with a vertical polarization feed, the fourth metal patch layer 25 is provided with a horizontal polarization feed, and the fifth metal patch layer 27 is a metal ground plane.

[0037] The bottom plate 3 is a metal bottom plate, which serves as a fixed mounting plate and a reflector. Properly increasing the size of the bottom plate can improve the front-to-back ratio of the antenna unit. The upper surface of the bottom plate 3 is in contact with the lower surface of the fifth metal patch layer 27. Furthermore, the bottom plate 3 is provided with a screw fixing hole 31 and a coaxial RF connector avoidance hole 32.

[0038] In a specific application example, the first metal patch layer 11 is used as a radiation patch, adopts a square design, and loads orthogonal cross gaps 15 on the square patch to increase two orthogonal polarized current paths, thereby reducing the size of the square patch. x The slot length in the axial direction mainly affects the vertical polarization working frequency band offset. yThe slot length in the axial direction mainly affects the horizontal polarization working band offset. Increasing the slot length can reduce the size of the radiation patch, but too large a length will also deteriorate the bandwidth, radiation pattern, impedance matching and other performances of the antenna, which need to be comprehensively considered in the actual design. It can be understood that in addition to the square design, the first metal patch layer 11 as a radiation patch is also applicable to rectangular, circular, polygonal and other plane shapes, and should also fall within the scope of protection of the present invention.

[0039] As a preferred embodiment, the support height of the nylon column 14 is consistent with the distance from the lower surface of the first dielectric layer 12 to the upper surface of the second metal patch layer 21. By adjusting the support height, broadband electromagnetic coupling between the radiation layer 1 and the dual-polarization feeding layer 2 can be achieved. In specific applications, the support height is generally about 1 / 10 of the center frequency wavelength.

[0040] As a preferred embodiment, the shape of the orthogonal coupling slot provided on the second metal patch layer 21 is composed of a square opening loaded with two pairs of inwardly protruding conical metal ridges 211 and 212, and the square opening is surrounded by metallized through holes 28 to form a square resonant cavity. The larger the cavity, the lower the resonant frequency. The sizes of the coupling slots in the two polarization directions can be adjusted respectively by adjusting the sizes of the conical metal ridges 211 and 212. The size of the coupling slot is inversely proportional to the vertical height from the feed line to the coupling slot, thereby achieving good impedance matching performance when the two polarization feeds are in different metal layers.

[0041] As a preferred embodiment, the vertical polarization feed set on the third metal patch layer 23 and the horizontal polarization feed set on the fourth metal patch layer 25 are both composed of a strip line loaded with an open-circuit fan-shaped junction, and input impedance matching is achieved by adjusting the open-circuit branch length and fan-shaped junction size of the two feeds.

[0042] As a preferred embodiment, both feed inputs are excited by a coaxial RF connector 29 to facilitate connection of the antenna with external devices; however, in an integrated design, the antenna of the present invention can also be directly connected to other devices through a quasi-coaxial metallized through hole or strip line, which should also be within the scope of protection of the present invention.

[0043] The following is an antenna designed in a specific application example of the present invention. The dual-polarized patch antenna in this embodiment has an operating frequency range of 2.0-2.4 GHz. The radiation layer 1 is a single-layer PCB board with a dielectric board thickness of 1 mm. The dual-polarized feeding layer 2 is a four-layer laminated PCB board with three dielectric boards having thicknesses of 0.55, 0.4, and 0.55 mm from top to bottom, respectively. The dielectrics used in the two PCB boards are both FR-4 with a relative dielectric constant of 4.4, a loss tangent of 0.02, a copper coating thickness of 0.035 mm, and a plane size of 52×52 mm, which is only 0.42 times λ H ; Support height of nylon column 14H 1=10mm; the bottom plate 3 is mainly used for fixing and enhancing forward radiation, and can be designed to be larger than the antenna PCB size to improve the front-to-back ratio and gain of the antenna unit. In the present invention, the plane size of the bottom plate 3 is 80×80mm.

[0044] The square radiation patch of the first metal patch layer 11 has a plane size of 41.8×41.8 mm and a cross gap width of W 1=0.5mm, x Gap length in the axial direction L 1=27mm, y Gap length in the axial direction L 2=30mm.

[0045] The side length of the square resonant cavity surrounded by the metallized through hole 28 is L 3 = 37.2 mm, the diameter of the metallized through hole 28 is 1 mm, and the interval between adjacent metallized through holes is 1.85 mm; the maximum width of the conical metal ridges 211 and 212 W 2=15.6mm, small width size W 3=2mm; the maximum length dimension of the metal ridge 211 L 4=17mm, small length dimension L 5=9.8mm; the maximum length dimension of the metal ridge 211 L 6=18.3mm, small length dimension L 7=10.7mm.

[0046] The vertical polarization feed provided by the third metal patch layer 23 and the horizontal polarization feed provided by the fourth metal patch layer 25 are both 50 ohm strip lines with a line width of 0.66 mm. The length from the open end of the vertical polarization feed to the center of the coupling slot is L 8 = 3.9mm, the fan-shaped junction angle is 30°, the radius is 3mm; the length from the open end of the horizontal polarization feed to the center of the coupling slot L 9=8.9mm, the fan-shaped angle is 45° and the radius is 4.1mm.

[0047] The two feed input ends of the dual-polarization feed layer 2 are respectively provided with RF connector mounting holes, the diameter of the middle coaxial core through hole is 1mm, the diameter of the surrounding ground pin through holes is 1.3mm, and the hole walls are metallized; the coaxial RF connector is fixed on the dual-polarization feed layer PCB board by welding.

[0048] like Figure 6The figure shows the S parameters of each port of the broadband dual-polarized patch antenna in this embodiment. It can be seen from the figure that the reflection coefficients of the two ports both meet <-10dB in the 1.97-2.43GHz frequency band, and the relative impedance bandwidth can reach 20.9%, which has a wide-band characteristic; the port isolation is greater than 34.5dB, which has a high isolation characteristic.

[0049] The radiation pattern of the vertically polarized antenna at the center frequency of 2.2 GHz is as follows Figure 7 The radiation pattern of horizontal polarization at the center frequency of 2.2 GHz is shown as follows Figure 8 The peak gain of the antenna is shown as Fig. 9 From the above simulation results, it can be seen that the antenna cross-polarization isolation is greater than 25dB, and the antenna gain in the 2.0-2.4GHz operating frequency band is >6.0dBi.

[0050] In order to verify the scanning performance of the antenna of the present invention in phased array applications, a 1×8 one-dimensional scanning array is formed based on the dual-polarized patch antenna of the present invention. Fig.10 , the interval between adjacent antenna units is 60 mm, which is 0.48 times λ H ;like Figure 11-12 The simulated radiation patterns of vertical polarization and horizontal polarization in azimuth plane scanning are shown in the figure. From the scanning results, it can be seen that within the scanning range of 0°-52°, the gain drop is within 3dB and no grating lobe appears.

[0051] In summary, the broadband dual-polarized patch antenna proposed in the present invention has an impedance bandwidth of more than 20%, stable radiation performance within the working frequency band, port isolation of more than 34dB, cross-polarization isolation of more than 25dB, and a unit plane size of only 0.42 times λ H It has a large-angle scanning performance of ±52°. The antenna PCB avoids blind hole design and has few layers. It has the advantages of broadband, compactness, low cost, high isolation and easy assembly. It is a powerful choice for dual-polarization radars or communication systems such as MIMO arrays and phased arrays.

[0052] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A broadband dual-polarized patch antenna, characterized in that: include: A radiation layer (1), a dual-polarization feeding layer (2) and a bottom plate (3) are arranged in sequence from top to bottom; The radiation layer (1) comprises a first metal patch layer (11) and a first dielectric layer (12); the first metal patch layer (11) is arranged on the upper surface of the first dielectric layer (12); The dual-polarization feed layer (2) comprises a second metal patch layer (21), a second dielectric layer (22), a third metal patch layer (23), a third dielectric layer (24), a fourth metal patch layer (25), a fourth dielectric layer (26), a fifth metal patch layer (27), and a metallized through hole (28) arranged from top to bottom; a coupling gap is provided on the second metal patch layer (21), a vertical polarization feed is provided on the third metal patch layer (23), a horizontal polarization feed is provided on the fourth metal patch layer (25), and the fifth metal patch layer (27) is a metal ground plane; The bottom plate (3) serves as a fixed mounting plate and a reflecting plate.

2. The broadband dual-polarized patch antenna according to claim 1, characterized in that: The first metal patch layer (11) serves as a radiation patch, and an orthogonal cross slot (15) is loaded on the radiation patch to increase two orthogonally polarized current paths.

3. The broadband dual-polarized patch antenna according to claim 2, characterized in that: The first metal patch layer (11) is in the shape of a square, a rectangle, a circle, or a polygon.

4. The broadband dual-polarized patch antenna according to any one of claims 1 to 3, characterized in that: An orthogonal coupling slot is provided on the second metal patch layer (21), the orthogonal coupling slot being formed by a square opening loaded with two pairs of inwardly protruding conical metal ridges (211, 212), the square opening being surrounded by metallized through holes (28) to form a square resonant cavity.

5. The broadband dual-polarized patch antenna according to any one of claims 1 to 3, characterized in that: The third metal patch layer (23) is provided with a vertical polarization feed, and the fourth metal patch layer (25) is provided with a horizontal polarization feed. Both the vertical polarization feed and the horizontal polarization feed are formed by a strip line loaded with an open circuit fan-shaped junction, and input impedance matching is achieved by adjusting the length of the open circuit branches and the size of the fan-shaped junction of the two feeds.

6. The broadband dual-polarized patch antenna according to claim 5, characterized in that: The inputs of the vertical polarization feed and the horizontal polarization feed are both excited by using a coaxial radio frequency connector (29).

7. The broadband dual-polarized patch antenna according to any one of claims 1 to 3, characterized in that: A plurality of screw fixing holes are provided at the corners of the first dielectric layer (12), and the first dielectric layer (12) is supported and fixed by nylon screws (13) and nylon columns (14).

8. The broadband dual-polarized patch antenna according to claim 7, characterized in that: The support height of the nylon column (14) is consistent with the distance from the lower surface of the first dielectric layer (12) to the upper surface of the second metal patch layer (21), and broadband electromagnetic coupling between the radiation layer (1) and the dual-polarization feeding layer (2) is achieved by adjusting the support height.

9. The broadband dual-polarized patch antenna according to any one of claims 1 to 3, characterized in that: The bottom plate (3) is a metal bottom plate, and the upper surface of the bottom plate (3) is bonded to the lower surface of the fifth metal patch layer (27).

10. The broadband dual-polarized patch antenna according to claim 9, characterized in that: The bottom plate (3) is provided with a screw fixing hole (31) and a coaxial radio frequency connector avoidance hole (32).

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