A patch antenna for improving the circularity of radiation pattern and its application

Abstract

The present invention discloses a patch antenna for improving the circularity of the radiation pattern and its application. The patch antenna includes a first metal floor, a dielectric layer, and a second metal floor which are sequentially stacked. On the surface of the dielectric layer away from the first metal floor, a transmitting antenna and a receiving antenna are provided. The transmitting antenna and the receiving antenna are spaced from the second metal floor, and the first metal floor is provided with a first slot and a second slot at intervals. By opening slots on the metal floor away from the transmitting antenna and the receiving antenna, additional parasitic radiation is introduced. The introduced parasitic radiation can compensate for the radiation blind spots of the traditional patch antenna and improve the circularity distortion problem of the radiation pattern of the patch antenna. Especially in the case of low elevation angles, the circularity of the radiation pattern of the patch antenna is greatly improved. The structure of this patch antenna has little modification to the traditional patch antenna, has low requirements for the structure of the patch antenna, is easy to produce and process, and has low cost. It is particularly suitable for use as the antenna of a radar sensor.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave communication, and relates to a patch antenna and its application, specifically to a patch antenna for improving the circularity of the radiation pattern and its application. Background Art

[0002] In recent years, with the continuous improvement of the complexity of the application scenarios of electronic products, the performance requirements for antennas in wireless communication systems and sensor systems have become increasingly high. Especially for the performance of the antenna radiation pattern, for indoor sensors, it is often required that the radiation pattern of the antenna is uniformly omnidirectional in the azimuth plane at different elevation angles to ensure a uniform and consistent coverage range in different azimuth planes, so as to meet the actual application needs.

[0003] Among many types of antennas, patch antennas are widely used in various indoor sensors due to their low profile, light weight, easy processing, and low cost. However, since microstrip patch antennas need to satisfy half-wavelength resonance and usually require two symmetrically arranged microstrip patch antennas as the receiving antenna and the transmitting antenna respectively, they occupy a relatively large space. At the same time, since the antenna needs to be connected to the chip and other circuits, the antenna inevitably deviates from the center of the floor and even needs to be placed at the edge of the floor. This placement method will cause the radiation pattern of the microstrip patch antenna to be distorted and the circularity of the radiation pattern to deteriorate, resulting in the problem of radiation pattern blind spots.

[0004] The traditional half-wave resonance microstrip patch antenna has a broadside radiation pattern. When the microstrip patch antenna is placed on an infinite floor, the radiation pattern of the microstrip patch antenna has no distortion and the circularity of the radiation pattern is good. However, generally, the patch antennas used in indoor sensors are mostly suspended and installed on the ceiling. When the z-axis is selected perpendicular to the bottom surface, the shape of the gain radiation pattern of the antenna in the cross-section at different elevation angles θ will directly affect the signal coverage range. To evaluate the performance of the antenna signal coverage, the antenna has an important parameter: the radiation pattern non-circularity, which is defined as the maximum gain difference in the cross-section of the radiation pattern in the θ angle direction. The smaller the elevation angle θ, the better the circularity of the radiation pattern. For example, the circularity at the elevation angle θ = 0° is naturally better than that at the elevation angle θ = 60°. In practical applications, the radiation pattern near the cross-section at θ = 60° is generally concerned.

[0005] In theory, the influence of the diffraction of electromagnetic waves at the edge of the floor on the radiation pattern of the microstrip patch antenna can be reduced by choosing a large-sized floor. However, this will increase the cost and make the antenna size too large to be easily integrated into other circuits or electronic devices. It is also possible to place the antenna as close as possible to the center of the floor, making the two radiation edges of the microstrip patch antenna symmetric about the center of the floor, that is, making the H-plane of the patch antenna located as close as possible to the center of the floor. For example, the literature "Improving radiation-pattern distortion of a patch antenna having a finite ground plane" (IEEE Trans. Antennas and Propagat., vol. 51, no. 3, pp. 478-482, March 2003., T. Namiki, Y. Murayama and K. Ito) proposed a solution: several rectangular parts are dug out from two floor edges parallel to the two radiation edges of the patch, so that the diffraction fields generated by the equivalent magnetic currents at the floor edge cancel each other out, thereby reducing the influence of the diffraction of electromagnetic waves at the edge of the finite ground plane on the antenna pattern. However, this solution destroys the integrity of the floor and is not conducive to placing other circuits and miniaturizing the entire module system. For the monopole antenna, the literature "Improving Radiation Pattern Roundness of a Monopole Antenna Placed Off-Center Above a Circular Ground Plane Using Characteristic Mode Analysis" (IEEE Trans. Antennas Propagat., vol. 69, no. 2, pp. 1135-1139, Feb. 2021., H. Sheng and Z. N. Chen) proposed that when it is placed offset from the center of the floor, a circular ring structure can be added around the antenna to change the asymmetric boundary condition relative to the offset center of the floor into a symmetric boundary condition relative to the circular ring structure, which can improve the non-circularity of the radiation pattern of the monopole antenna. However, this solution requires a relatively large floor size, and the newly added structure increases the processing cost.The literature "Radiation Pattern Roundness Improvement of Off-center Monopole Antenna Using Electromagnetic Band-gap (EBG) Structure" (2021 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (APS / URSI), Singapore, Dec. 2021, pp. 1313-1314., B. Zhang and Z. N. Chen) proposed to use a suspended circular electromagnetic gap ring structure (CirEBG) to improve the pattern non-circularity of a monopole antenna offset and placed at the center of a square floor. The suspended circular electromagnetic gap ring structure concentrates the surface current on the floor at the boundary of a symmetric and adjustable ring structure, allowing more traveling waves to radiate out in the symmetric ring structure. At the same time, more energy is concentrated in the ring structure, and the radiation at the floor edge can be suppressed. However, this solution requires a relatively large floor size, which is not conducive to integration. The literature "A V-shape Edge-Groove Design for a Finite Ground Plane to Reduce Pattern Ripples of a Monopole" (Antennas Wirel.Propag.Lett., vol. 7, pp. 561-564, 2008., Hsing-Feng Chen, Meng-Yi Lin and Ken-Huang Lin) proposed to reduce the diffraction at the floor edge by weakening the traveling waves passing through it by loading a V-shaped edge groove on a circular floor. However, this V-shaped edge groove has relatively strict requirements on the thickness of the dielectric substrate, generally being one-fourth of the operating wavelength. Currently, there are few studies in the industry that propose other methods to improve the non-circularity of the radiation pattern of a patch antenna under a finite ground plane, and there are even fewer technologies that improve the circularity of the radiation pattern with the least change to the original floor structure.

[0006] In view of this, it is necessary to improve the patch antenna in the prior art and propose a patch antenna that improves the circularity of the pattern. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is that the circularity of the pattern of a traditional patch antenna is not ideal when the floor size is limited, which limits the application of the patch antenna. Thus, a patch antenna that improves the circularity of the pattern and its application are proposed.

[0008] To solve the above technical problems, the technical solution of the present invention is as follows:

[0009] In the first aspect of the present invention, a patch antenna for improving the circularity of the radiation pattern is provided, which includes a first metal floor, a dielectric layer, and a second metal floor stacked in sequence. On the surface of the dielectric layer away from the first metal floor, a transmitting antenna and a receiving antenna are provided, and the transmitting antenna, the receiving antenna are spaced apart from the second metal floor; the first metal floor is provided with a first slot and a second slot at intervals.

[0010] Preferably, the first metal floor is a rectangular plate, and the first slot and the second slot are symmetrically arranged on opposite sides of the first metal floor.

[0011] Preferably, the first slot and the second slot are rectangular slots with the same size, and the length of the rectangular slot is 0.1-0.4 times the dielectric wavelength.

[0012] Preferably, the width of the rectangular slot is 1 / 20-1 / 2 of the length.

[0013] Preferably, the first slot and the second slot are connected to the second metal floor through a shorting unit.

[0014] Preferably, along the horizontal direction, the first slot and the second slot are arranged at intervals on one side of the transmitting antenna and the receiving antenna, and the shorting unit is a group of metallized vias arranged on the side of the first slot and the second slot away from the transmitting antenna and the receiving antenna, and the metallized vias are arranged at intervals along the direction from the first slot to the second slot.

[0015] Preferably, the transmitting antenna and the receiving antenna are arranged at intervals, and the transmitting antenna and the receiving antenna are respectively connected to a radio frequency port through a feeding unit, and the radio frequency port is arranged on the first metal floor or the second metal floor.

[0016] Preferably, the first slot and the second slot are symmetrically arranged on both sides of the center line of a pair of opposite sides of the first metal floor.

[0017] In the second aspect of the present invention, an application of the patch antenna for improving the circularity of the radiation pattern in a radar sensor is provided.

[0018] The above technical solution of the present invention has the following advantages compared with the prior art:

[0019] The patch antenna for improving the circularity of the radiation pattern provided by the present invention comprises a first metal floor, a dielectric layer and a second metal floor which are sequentially stacked. An emitting antenna and a receiving antenna are arranged on the surface of the dielectric layer away from the first metal floor. The emitting antenna, the receiving antenna and the second metal floor are arranged at intervals. The first metal floor is provided with a first slot and a second slot at intervals. By opening slots on the metal floor far from the emitting antenna and the receiving antenna, additional parasitic radiation is introduced. The introduced parasitic radiation can compensate for the radiation blind spots of the traditional patch antenna and improve the circularity distortion problem of the radiation pattern of the patch antenna. Especially in the case of low elevation angles, the circularity of the radiation pattern of the patch antenna is greatly improved. The structure of this patch antenna has little modification to the traditional patch antenna, has low requirements for the structure of the patch antenna, is easy to produce and process, and has low cost, and is particularly suitable for being used as the antenna of a radar sensor. Description of the Drawings

[0020] In order to make the content of the present invention easier to be clearly understood, the following further describes the present invention in detail according to the specific embodiments of the present invention in conjunction with the drawings, wherein

[0021] Figure 1 is a schematic structural diagram of the patch antenna for improving the circularity of the radiation pattern provided in Embodiment 1 of the present invention;

[0022] Figure 2 is a schematic structural diagram of the patch antenna for improving the circularity of the radiation pattern provided in Embodiment 1 of the present invention from another angle;

[0023] Figure 3 is a schematic structural diagram of the patch antenna for improving the circularity of the radiation pattern provided in Embodiment 1 of the present invention from another angle;

[0024] Figure 4 is a schematic assembly structural diagram of the patch antenna for improving the circularity of the radiation pattern provided in Embodiment 1 of the present invention and components;

[0025] Figure 5 is a simulation data test curve graph of S11, S21, and S22 of a traditional patch antenna;

[0026] Figure 6 is a simulation data test curve graph of S11, S21, and S22 of the patch antenna provided in Embodiment 1;

[0027] Figure 7 is a rectangular coordinate graph of the radiation pattern non-circularity of a traditional patch antenna and the patch antenna provided in Embodiment 1;

[0028] Figure 8 is a polar coordinate graph of the radiation pattern non-circularity of a traditional patch antenna and the patch antenna provided in Embodiment 1;

[0029] Figure 9It is a schematic diagram of the surface current distribution of a traditional patch antenna;

[0030] Figure 10 It is a schematic diagram of the surface current distribution of the patch antenna provided in Embodiment 1;

[0031] Figure 11 It is a schematic diagram of the electric field intensity distribution of the patch antenna provided in Embodiment 1.

[0032] In the figure, the reference numerals are represented as follows: 1 - first metal floor; 101 - first slot; 102 - second slot; 2 - dielectric layer; 3 - second metal floor; 4 - transmitting antenna; 5 - receiving antenna; 6 - short - circuit unit; 7 - first microstrip feeder; 8 - second microstrip feeder; 9 - first via; 10 - second via. Detailed implementation manners

[0033] To make the objectives, 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 with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the products of the present invention are usually placed, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0035] The "first", "second", etc. in the present invention are only used for distinction in description and have no special meaning.

[0036] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed" 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 directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0037] Embodiment 1

[0038] This embodiment provides a patch antenna for improving the circularity of the radiation pattern. Please refer to Figures 1 - 4, the patch antenna includes a first metal floor 1, a dielectric layer 2, and a second metal floor 3 that are sequentially stacked. Among them, the first metal floor 1 has the same size as the dielectric layer 2 and is disposed on one surface of the dielectric layer. The second metal floor 3 has a size smaller than the dielectric layer 2 and is disposed on the other surface of the dielectric layer 2. The first metal floor 1 and the second metal floor 3 are used to mount electronic components and radio frequency circuits (such as Figure 4 as shown). A transmitting antenna 4 and a receiving antenna 5 are connected to the surface of the dielectric layer 2 away from the first metal floor 1. The transmitting antenna 4 and the receiving antenna 5 are spaced apart from the second metal floor 3. The first metal floor 1 is provided with a first slot 101 and a second slot 102 at intervals.

[0039] The patch antenna for improving the circularity of the radiation pattern provided in this embodiment introduces additional parasitic radiation to the patch antenna by providing slots at intervals on the first metal floor 1 on the side away from the transmitting antenna 4 and the receiving antenna 5. The introduced parasitic radiation can change the surface current distribution of the transmitting antenna 4, the receiving antenna 5, and the first metal floor 1. Compared with the traditional patch antenna without slots, the radiation participated by the first metal floor 1 is weakened, compensating for the radiation blind spot of the traditional patch antenna and improving the circularity distortion problem of the radiation pattern of the patch antenna. Especially in the case of a low elevation angle (θ = 60°), the circularity of the radiation pattern of the patch antenna is greatly improved. The structure of this patch antenna makes minor changes to the traditional patch antenna and has low requirements for the structure of the patch antenna: it does not require the symmetry of the first metal floor 1 itself, nor does it require the transmitting antenna 4 and the receiving antenna 5 to be located at the center of the second metal floor 3, making the selection of the shapes of the first metal floor 1 and the second metal floor 3 and the placement positions of the transmitting antenna 4 and the receiving antenna 5 more flexible, reducing the manufacturing difficulty, being more suitable for production and processing, having a low cost, and being suitable for use as the antenna of a radar sensor.

[0040] Preferably, in this embodiment, the first metal floor 1 adopts a rectangular sheet structure, including two groups of opposite sides. The first slot 101 and the second slot 102 are symmetrically provided inside the edges of one group of opposite sides of the first metal floor 1. As shown in the figure, the connection line of the first slot 101 and the second slot 102 is parallel to one group of opposite sides of the first metal floor 1 (i.e., perpendicular to the other group of opposite sides), and the first slot 101 and the second slot 102 are symmetrically provided on both sides of the midline of one group of opposite sides of the first metal floor 1.

[0041] Further, the first slot 101 and the second slot 102 are rectangular slots with the same size and structure. The first slot 101 and the second slot 102 are respectively arranged on a set of opposite side edges of the first metal floor 1 and extend towards the inside of the first metal floor 1. The midlines of the short sides of the first slot 101 and the second slot 102 are perpendicular to this set of opposite sides of the first metal floor 1. Moreover, the first short side of the first slot 101 coincides with one of this set of opposite sides of the first metal floor 1, the first short side of the second slot 102 coincides with the other of the above-mentioned opposite sides of the first metal floor 1, and the second short side of the first slot 101 and the second short side of the second slot 102 are spaced and oppositely arranged.

[0042] Wherein, the lengths of the first slot 101 and the second slot 102 are preferably 0.1 - 0.4 times the dielectric wavelength, and the widths are 1 / 20 - 1 / 2 of the lengths. Specifically, in this embodiment, the lengths of both the first slot 101 and the second slot 102 are 3.3 mm, and the widths are both 1 mm.

[0043] The first slot 101 and the second slot 102 are connected to the second metal floor 3 through the short - circuit unit 6. Specifically, in this embodiment, along the horizontal direction, the first slot 101 and the second slot 102 are spaced and arranged on one side of the transmitting antenna 4 and the receiving antenna 5, and the short - circuit unit 6 is arranged on the side of the first slot 101 and the second slot 102 away from the transmitting antenna 4 and the receiving antenna 5. Among them, the short - circuit unit 6 is a set of spaced and linearly arranged metallized vias. This set of metallized vias is spaced and arranged from one end of the first slot 101 to one end of the second slot 102, and the metallized vias are sequentially arranged along the edge of the first slot 101 away from the transmitting antenna 4 and the receiving antenna 5 to the edge of the second slot 102 away from the transmitting antenna 4 and the receiving antenna 5, that is, the metallized vias are sequentially and spacedly arranged along the first long side of the first metal floor 1 to the second long side, so as to connect the first metal floor 1 and the second metal floor 3. The metallized hole is composed of a through - hole penetrating the first metal floor 1, the dielectric layer 2, and the second metal floor 3 and a metal column filled in the through - hole. The material of the metal column is preferably copper.

[0044] As Figures 1 - 2As shown, in this embodiment, the cross-sectional shapes of the transmitting antenna 4 and the receiving antenna 5 are both rectangles, and the second metal floor 3 is also a rectangular plate, whose size is smaller than that of the dielectric substrate 2 and the first metal floor 1. It is spaced on one side of the transmitting antenna 4 and the receiving antenna 5. The transmitting antenna 4 and the receiving antenna 5 are symmetrically arranged with respect to the midline of the long side of the second metal floor 3. The first slot 101 and the second slot 102 are also symmetrically arranged with respect to the midline of the long side of the second metal floor 3. At the same time, the transmitting antenna 4 and the receiving antenna 5 are symmetrically arranged with respect to the midline of the short side of the first metal floor 1. The first slot 101 and the second slot 102 are also symmetrically arranged with respect to the midline of the short side of the first metal floor 1. With such an arrangement, the radiation pattern of the antenna is mirror-symmetric with respect to the midline of the first metal floor 1 or the second metal floor 3, thereby further improving the circularity of the antenna radiation pattern.

[0045] In the horizontal direction, a first microstrip feeder 7 is connected to the side of the transmitting antenna 4 close to the first slot 101 and the second slot 102, and a second microstrip feeder 8 is connected to the side of the receiving antenna 5 close to the first slot 101 and the second slot 102. The first microstrip feeder 7 and the second microstrip feeder 8 are arranged in an L-shaped structure facing each other. The transmitting antenna 4 and the receiving antenna 5 are respectively connected to a radio frequency port through a feeding unit, and the radio frequency port is arranged on the first metal floor 1 or the second metal floor 3. In this embodiment, the radio frequency port is arranged on the side of the first metal floor 1 away from the dielectric layer (that is, when the side with the transmitting antenna 4 and the receiving antenna 5 is the front of the patch antenna, the radio frequency port is arranged on the back of the patch antenna). Among them, the feeding unit includes a first via 9 connected to the transmitting antenna 4 and a second via 10 connected to the receiving antenna 5. The transmitting antenna 4 is connected to the radio frequency port on the other side of the first metal floor 1 through the first via 9, and the receiving antenna 5 is connected to the radio frequency port on the other side of the first metal floor 1 through the second via 10. The above setting method of the first via 9 and the second via 10 can satisfy both the case where the dielectric layer 2 is a single layer and the case where the dielectric layer 2 is a multi-layer. In this embodiment, the dielectric layer 2 uses a dielectric substrate made of FR-4.

[0046] The patch antenna for improving the circularity of the pattern provided in this embodiment, based on a simple improvement of the antenna structure, greatly improves the circularity of the pattern of the patch antenna, and is particularly suitable for the antenna of an indoor ceiling radar sensor.

[0047] Experimental example

[0048] 1. Respectively test the simulation data of S11, S21, and S22 of the traditional patch antenna without the first slot 101 and the second slot 102 and the patch antenna provided in Embodiment 1. The test results are as Figures 5 - 6 shown, where Figure 5 is the simulation data test curve graph of S11, S21, and S22 of the traditional patch antenna.Figure 6 It is the simulation data test curve graph of S11, S21, and S22 of the patch antenna provided in Embodiment 1.

[0049] From Figure 5 it can be seen that in the traditional patch antenna, the operating frequencies of the receiving antenna and the transmitting antenna completely coincide. The center operating frequency is 10.52 GHz, the matching and isolation are good, and the frequency band with S11 less than -10 dB is about 0.43 GHz. The isolation of the transceiver antenna within the -10 dB bandwidth is higher than -18.89 dB.

[0050] From Figure 6 it can be seen that for the patch antenna provided in Embodiment 1, after the first slot 101 and the second slot 102 are opened on the first metal floor 1, the operating frequencies of the transmitting antenna 4 and the receiving antenna 5 completely coincide. The center operating frequency is 10.45 GHz, the matching and isolation are good, and the frequency band with S11 less than -10 dB is about 0.47 GHz. The isolation of the transceiver antenna within the -10 dB bandwidth is higher than -19.82 dB. This shows that setting slots on the first metal floor 1 extends the current path, slightly reducing the center frequency, but fully meeting the requirements of the required bandwidth and isolation.

[0051] 2. Respectively test the rectangular coordinate and polar coordinate graphs of the pattern non-circularity of the traditional patch antenna without the first slot 101 and the second slot 102 and the patch antenna provided in Embodiment 1. The test results are as Figures 7 - 8 shown, where Figure 7 is the rectangular coordinate graph of the pattern non-circularity of the traditional patch antenna and the patch antenna provided in Embodiment 1, Figure 8 is the polar coordinate graph of the pattern non-circularity of the traditional patch antenna and the patch antenna provided in Embodiment 1.

[0052] From the above test results, it can be seen that in the radiation pattern at a low elevation angle (θ = 60°), the pattern non-circularity of the traditional patch antenna is 7.23 dB; for the patch antenna provided in Embodiment 1, after setting the first slot 101 and the second slot 102 on the first metal floor 1, the pattern non-circularity is 2.52 dB, and the pattern non-circularity is improved by 4.71 dB. This shows that compared with the traditional patch antenna, the patch antenna provided in Embodiment 1 with the first slot 101 and the second slot 102 set on the first metal floor 1 has an obvious improvement effect on the pattern non-circularity at a low elevation angle, solves the technical problem of the pattern blind spot of the patch antenna, and is more suitable for the antenna of the indoor ceiling radar sensor.

[0053] 3. Figures 9 - 10Schematic diagrams of the surface current distribution of a traditional patch antenna without the first slot 101 and the second slot 102 and the patch antenna provided in Embodiment 1 are shown. It can be seen from the figures that by setting the first slot 101 and the second slot 102, compared with the traditional patch antenna, the current distribution on the antenna surface is changed, so that when the patch antenna is at a low elevation angle (θ = 60°), the radiation pattern is changed and the circularity is significantly improved. At this time, the transmitting antenna 4 is independently excited.

[0054] 4. Figure 11 Schematic diagram of the electric field distribution of the patch antenna provided in Embodiment 1 is shown. It can be seen from the figure that by setting the first slot 101 and the second slot 102, only the tangential electric field intensity exists in the slots. The distribution direction of the electric field intensity is perpendicular to the length direction of the slots, and the field distribution in the slots is approximately a distribution of 1 / 4 cycle or 1 / 4 wavelength resonance. The first slot 101 and the second slot 102 opened in the first metal floor 1 generate additional parasitic radiation, and the additional parasitic radiation plays a technical effect of compensating for the radiation blind spot of the traditional patch antenna and improving the non-circularity of the radiation pattern of the patch antenna.

[0055] Obviously, the above embodiments are only examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A patch antenna for improving the circularity of the radiation pattern, characterized in that, It includes a first metal floor, a dielectric layer, and a second metal floor that are sequentially stacked. On the surface of the dielectric layer away from the first metal floor, there is a transmitting antenna and a receiving antenna, and the transmitting antenna and the receiving antenna are spaced apart from the second metal floor; the first metal floor is provided with a first slot and a second slot at intervals; the first slot and the second slot are connected to the second metal floor through a shorting unit; In the horizontal direction, the first slot and the second slot are spaced apart on one side of the transmitting antenna and the receiving antenna, and the shorting unit is a group of metallized vias provided on the side of the first slot and the second slot away from the transmitting antenna and the receiving antenna, and the metallized vias are arranged at intervals along the direction from the first slot to the second slot.

2. The patch antenna for improving the circularity of the radiation pattern according to claim 1, wherein The first metal floor is a rectangular plate, and the first slot and the second slot are symmetrically opened on opposite sides of the first metal floor.

3. The patch antenna for improving the circularity of the radiation pattern according to claim 2, wherein The first slot and the second slot are rectangular slots with the same size, and the length of the rectangular slot is 0.1 - 0.4 times the dielectric wavelength.

4. The patch antenna for improving the roundness of the radiation pattern according to claim 3, wherein The width of the rectangular slot is 1 / 20 - 1 / 2 of the length.

5. The patch antenna for improving the circularity of the radiation pattern according to claim 4, wherein The transmitting antenna and the receiving antenna are spaced apart, and the transmitting antenna and the receiving antenna are respectively connected to a radio frequency port through a feeding unit, and the radio frequency port is arranged on the first metal floor or the second metal floor.

6. The patch antenna for improving the circularity of the radiation pattern according to claim 5, wherein The first slot and the second slot are symmetrically arranged on both sides of the center line of a pair of opposite sides of the first metal floor.

7. Application of a patch antenna for improving the circularity of the radiation pattern according to any one of claims 1 - 6 in a radar sensor.

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