Multi-mode broadband circularly polarized non-uniform metasurface antenna based on slots and stub loading

Abstract

The application discloses a kind of multi-mode broadband circular polarization non-uniform super surface antennas based on gap and branch loading, including first dielectric substrate, second dielectric substrate and feed probe;First dielectric substrate lower surface is equipped with metal floor, upper surface is equipped with driving patch;Second dielectric substrate upper surface is equipped with non-uniform super surface;Driving patch middle is square patch, a cross-shaped gap is etched on square patch;Square patch four corners each is equipped with one identical L-shaped branch;Square patch one side is equipped with T-shaped feed line;Non-uniform super surface is composed of four square patches with a pair of corner cutting in the middle and twelve square patches in the periphery;Feed probe is close to the center of T-shaped feed line, and is connected with T-shaped feed line by passing through metal floor and first dielectric substrate in turn.The application realizes the broadband circular polarization characteristics with four circular polarization radiations under lower profile.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading. Background Technology

[0002] Compared to linearly polarized antennas, circularly polarized antennas possess superior characteristics such as resistance to polarization mismatch, reduced multipath interference, and Faraday rotation effect, making them widely used in wireless communication systems. Microstrip antennas have a simple structure, but their inherent narrowband characteristics limit their applications; in practice, increasing the profile is often used to extend bandwidth. Compared to microstrip antennas, metasurface antennas offer superior low-profile, wide bandwidth. Traditional circularly polarized antennas are often implemented using dual-mode technology, but incorporating multimode techniques from broadband linearly polarized antennas into circularly polarized antenna design can effectively extend the bandwidth of circularly polarized antennas. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading. The antenna is divided into two layers. The lower layer obtains two circularly polarized radiation modes through cross slot and L-shaped stub loading, and the upper layer obtains two circularly polarized radiation modes through non-uniform metasurface. The lower layer patch is used as the driving patch to couple and excite the circularly polarized modes of the upper metasurface, thus achieving broadband circular polarization characteristics with four circularly polarized radiation modes.

[0004] To achieve the above objectives, the technical solution provided by this invention is as follows: a multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading, comprising a first dielectric substrate, a second dielectric substrate, and a feed probe; a metal ground plane is disposed on the lower surface of the first dielectric substrate, and a driving patch is disposed on the upper surface; the second dielectric substrate is stacked on the upper surface of the first dielectric substrate, and a non-uniform metasurface is disposed on the upper surface of the second dielectric substrate; the driving patch has a square patch in the middle, a cross-shaped slot is etched in the middle of the square patch, and an identical L-shaped stub is disposed at each of the four corners of the square patch, respectively realizing two circular polarizations. Radiation is achieved by setting a T-shaped feed line on one side of the square patch for impedance matching; the non-uniform metasurface consists of four first metasurface units arranged in a rectangle at the center and twelve second metasurface units on the periphery, which respectively realize two circularly polarized radiations; the first metasurface unit is a square patch with two chamfered corners, that is, a pair of corners are cut off along one diagonal of the square patch, and the chamfers are used to adjust the low-frequency axial ratio; the second metasurface units are square patches with different sizes than the first metasurface units; the feed probe is close to the center of the T-shaped feed line and passes through the metal ground plane and the first dielectric substrate in sequence to connect to the T-shaped feed line.

[0005] Furthermore, the long and short sides of the cross-shaped slit are respectively located on the two diagonals of the square patch.

[0006] Furthermore, the diagonal line where the chamfer is located is parallel to the long side of the cross-shaped slit.

[0007] Furthermore, the L-shaped branch is rotationally symmetrical about the center of the square patch.

[0008] Furthermore, the T-shaped feed line is offset from the central axis of the square patch.

[0009] Furthermore, the side length of the first metasurface unit is greater than the side length of the second metasurface unit.

[0010] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0011] 1. The antenna of the present invention obtains two circularly polarized radiations by loading a cross-shaped slot and an L-shaped stub on a square patch, and obtains two additional circularly polarized radiations by changing the size of the four first metasurface units at the center of the non-uniform metasurface and the twelve second metasurface units on the periphery. The combination of the two achieves broadband circularly polarized characteristics with four circularly polarized radiations.

[0012] 2. The antenna of this invention employs a non-uniform metasurface structure with a cross-shaped slot and L-shaped stub loading, achieving |S| at a profile height of 0.07λ0 (λ0 is the wavelength corresponding to the center frequency). 11 The impedance bandwidth of -10dB is 44.4%, the axial ratio bandwidth of <3dB is 43.4%, the 3dB gain bandwidth is 39.8%, and the effective overlap bandwidth is 39.8%. The peak gain within the operating bandwidth is 8.53dBic, resulting in good broadband right-hand circular polarization characteristics. Attached Figure Description

[0013] Figure 1 This is a three-dimensional structural schematic diagram of a multimode broadband circularly polarized non-uniform metasurface antenna according to an embodiment of the present invention.

[0014] Figure 2 This is a schematic diagram of the left-side structure of a multimode broadband circularly polarized non-uniform metasurface antenna according to an embodiment of the present invention.

[0015] Figure 3 This is a schematic diagram of the structure of the driver patch according to an embodiment of the present invention.

[0016] Figure 4 This is a schematic diagram of the structure of a non-uniform metasurface according to an embodiment of the present invention.

[0017] Figure 5 The image shows the simulated S-parameter curves of the multimode broadband circularly polarized non-uniform metasurface antenna according to an embodiment of the present invention.

[0018] Figure 6 The simulated axial ratio and gain curves of the multimode broadband circularly polarized non-uniform metasurface antenna according to an embodiment of the present invention are shown.

[0019] Figure 7 This is the radiation pattern of the multimode broadband circularly polarized non-uniform metasurface antenna in the xoz plane at 4 GHz, according to an embodiment of the present invention.

[0020] Figure 8 This is the radiation pattern of the multimode broadband circularly polarized non-uniform metasurface antenna in the yoz plane at 4 GHz, according to an embodiment of the present invention.

[0021] Figure 9 This is the radiation pattern of the multimode broadband circularly polarized non-uniform metasurface antenna in the xoz plane at 4.8 GHz, according to an embodiment of the present invention.

[0022] Figure 10 This is the radiation pattern of the multimode broadband circularly polarized non-uniform metasurface antenna in the yoz plane at 4.8 GHz, according to an embodiment of the present invention.

[0023] Figure 11 This is the radiation pattern of the multimode broadband circularly polarized non-uniform metasurface antenna in the xoz plane at 5.6 GHz, according to an embodiment of the present invention.

[0024] Figure 12 This is the radiation pattern of the multimode broadband circularly polarized non-uniform metasurface antenna in the yoz plane at 5.6 GHz, according to an embodiment of the present invention.

[0025] Figure 13 This is a top view of the non-uniform metasurface structure according to an embodiment of the present invention.

[0026] Figure 14 This is a top view of the drive patch structure according to an embodiment of the present invention.

[0027] Wherein, 1-first dielectric substrate, 2-second dielectric substrate, 3-non-uniform metasurface, 4-driving patch, 5-metal ground plane, 6-feed probe, 7-cross-shaped slit, 8-L-shaped stub, 9-T-shaped feed line, 10-first metasurface unit, 11-second metasurface unit. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0029] Microstrip antennas fabricated using PCB technology are characterized by their small size, light weight, low cost, and ease of planar integration. Compared to microstrip antennas, metasurface antennas offer the advantage of low profile bandwidth and can be fabricated using the same PCB technology. Circularly polarized antennas have broad application prospects in satellite, mobile communication, and sensing systems. Compared to linearly polarized antennas, circularly polarized antennas offer advantages such as insensitivity to antenna axial rotation, low propagation delay, and resistance to multipath interference and Faraday rotation. Furthermore, broadband antennas can operate over a wide frequency range to adapt to different operating scenarios. Therefore, this embodiment provides a multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading.

[0030] like Figures 1 to 4 As shown, this embodiment provides a multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading, including a first dielectric substrate 1, a second dielectric substrate 2, and a feed probe 6; both the first dielectric substrate 1 and the second dielectric substrate 2 are made of F4B material with a dielectric constant of 3.0, a loss tangent of 0.0015, and a thickness of 2mm; a metal ground plane 5 is disposed on the lower surface of the first dielectric substrate 1, and a driving patch 4 is disposed on the upper surface; the second dielectric substrate 2 is stacked on the upper surface of the first dielectric substrate 1, and a non-uniform metasurface 3 is disposed on the upper surface of the second dielectric substrate 2; the driving patch 4 has a square patch in the middle, a cross-shaped slot 7 is etched in the middle of the square patch, and each of the four corners of the square patch has a cross-shaped slot 7. An identical L-shaped stub 8 is set up to achieve two circularly polarized radiations. A T-shaped feed line 9 is set on one side of the square patch to achieve impedance matching. The non-uniform metasurface 3 consists of four first metasurface units 10 arranged in a rectangle at the center and twelve second metasurface units 11 on the periphery, which respectively achieve two circularly polarized radiations. The first metasurface unit 10 is a square patch with two chamfered corners, that is, a pair of corners are cut off along one diagonal of the square patch. The chamfered corners are used to adjust the low-frequency axial ratio. The second metasurface unit 11 is a square patch with a different size than the first metasurface unit 10. The feed probe 6 is close to the center of the T-shaped feed line 9 and passes through the metal ground plane 5 and the first dielectric substrate 1 in sequence to connect with the T-shaped feed line 9.

[0031] Specifically, the long and short sides of the cross-shaped slit 7 are respectively on the two diagonals of the square patch; the diagonal where the chamfer is located is parallel to the long side of the cross-shaped slit 7; the L-shaped branch 8 is rotationally symmetrical about the center of the square patch; the T-shaped feed line 9 deviates from the central axis of the square patch and is offset to the right by a certain distance; the side length of the first metasurface unit 10 is greater than the side length of the second metasurface unit 11.

[0032] like Figure 5As shown, the simulated S-parameter curves of the multimode broadband circularly polarized non-uniform metasurface antenna described in this embodiment are displayed. From the figure, we can see that the antenna |S 11 The bandwidth of |<-10dB is approximately 44.4% (3.68-5.78GHz), and it is used in the C-band.

[0033] like Figure 6 The figure shows the simulated axial ratio and gain curves of the multimode broadband circularly polarized non-uniform metasurface antenna described in this embodiment along the positive z-axis. It can be seen from the figure that the antenna's bandwidth (AR < 3dB) is approximately 43.4% (3.86-6GHz), and the antenna simultaneously satisfies |S... 11 The bandwidth of |<-10dB and axial ratio<3dB is approximately 39.8% (3.86-5.78GHz). Within this frequency band, the antenna has a maximum gain of 8.53dBic and a minimum gain of 5.5dBic, achieving wideband circular polarization characteristics.

[0034] like Figure 7 and Figure 8 The figure shows the radiation field patterns of the multimode broadband circularly polarized non-uniform metasurface antenna described in this embodiment at 4 GHz in the xoz and yoz planes. It can be seen from the figure that the main polarization of the antenna at this frequency is right-hand circular polarization, which has good directional circular polarization radiation characteristics and cross-polarization is less than -10 dB.

[0035] like Figure 9 and Figure 10 The figure shows the radiation field patterns of the multimode broadband circularly polarized non-uniform metasurface antenna described in this embodiment at 4.8 GHz in the xoz and yoz planes. It can be seen from the figure that the main polarization of the antenna at this frequency is right-hand circular polarization, which has good directional circular polarization radiation characteristics and cross-polarization is less than -10 dB.

[0036] like Figure 11 and Figure 12 The figure shows the radiation field patterns of the multimode broadband circularly polarized non-uniform metasurface antenna described in this embodiment at 5.6 GHz in the xoz and yoz planes. It can be seen from the figure that the main polarization of the antenna at this frequency is right-hand circular polarization, which has good directional circular polarization radiation characteristics and cross-polarization is less than -10 dB.

[0037] like Figure 13 and Figure 14 The diagram shows the top view of the multimode broadband circularly polarized non-uniform metasurface antenna described in this embodiment. The specific dimensions of the antenna are as follows:

[0038] W g =51.9mm,w 11 =11.6mm,w22 =11.1mm,g=1.5mm,t=2.2mm,w p =13.7mm,

[0039] l1=15.8mm, w1=1.3mm, l2=7.5mm, w2=2mm, lb1=8.7mm, lb2=14.1mm,

[0040] wb=2.3mm, lf=6.6mm, wf=1.4mm, d=2mm, x f =8.05mm

[0041] In summary, the antenna of this invention obtains two circularly polarized radiations by etching a cross-shaped slot and loading an L-shaped stub on a square patch; then, by replacing the metasurface with a non-uniform metasurface with inconsistent inner and outer dimensions, two additional circularly polarized radiations are obtained. These four circularly polarized radiations are excited simultaneously by feeding the drive patch, thus achieving broadband circular polarization characteristics. This antenna achieves |S| at a profile height of 0.07λ0. 11 The impedance bandwidth of -10dB is 44.4%, the axial ratio bandwidth of <3dB is 43.4%, the 3dB gain bandwidth is 39.8%, and the effective overlap bandwidth is 39.8%. The peak gain within the operating bandwidth is 8.53dBic, resulting in good broadband right-hand circular polarization characteristics.

[0042] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading, characterized in that, The system includes a first dielectric substrate (1), a second dielectric substrate (2), and a feed probe (6). A metal ground plane (5) is disposed on the lower surface of the first dielectric substrate (1), and a driving patch (4) is disposed on its upper surface. The second dielectric substrate (2) is stacked on the upper surface of the first dielectric substrate (1), and a non-uniform metasurface (3) is disposed on the upper surface of the second dielectric substrate (2). The driving patch (4) has a square patch in the center, a cross-shaped slit (7) is etched in the center of the square patch, and an identical L-shaped stub (8) is disposed at each of the four corners of the square patch to achieve two circularly polarized radiations. A T-shaped feed line is disposed on one side of the square patch. (9) is used to achieve impedance matching; the non-uniform metasurface (3) is composed of four first metasurface units (10) arranged in a rectangular shape in the center and twelve second metasurface units (11) in the periphery, which respectively realize two circular polarization radiation; the first metasurface unit (10) is a square patch with two chamfered corners, that is, a pair of corners are cut off in the direction of one diagonal of the square patch, and the chamfered corners are used to adjust the low frequency axial ratio; the second metasurface unit (11) is a square patch with a different size than the first metasurface unit (10); the feed probe (6) is close to the center of the T-shaped feed line (9) and passes through the metal ground plane (5) and the first dielectric substrate (1) in sequence to connect with the T-shaped feed line (9).

2. The multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading according to claim 1, characterized in that, The long and short sides of the cross-shaped slit (7) are on the two diagonals of the square patch, respectively.

3. The multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading according to claim 2, characterized in that, The diagonal line where the cut angle is located is parallel to the long side of the cross-shaped slit (7).

4. The multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading according to claim 3, characterized in that, The L-shaped branch (8) is rotationally symmetrical about the center of the square patch.

5. The multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading according to claim 4, characterized in that, The T-shaped feed line (9) is offset from the central axis of the square patch.

6. The multimode broadband circularly polarized non-uniform metasurface antenna based on slot and stub loading according to claim 5, characterized in that, The side length of the first metasurface unit (10) is greater than the side length of the second metasurface unit (11).

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