Radar sensor with ultra-small floor and backward radiation suppression

Abstract

The invention discloses a radar sensor with an ultra-small floor and backward radiation suppression, which comprises a main floor and at least one parasitic floor, and a gap is formed between the parasitic floor and the main floor; the connecting resistor is electrically connected with the main floor and the parasitic floor. The first radiating body and the second radiating body are arranged in a spaced manner, and the first radiating body and the second radiating body are positioned above the first surface of the main floor; one end of the first feed probe is connected with the first radiator, and one end of the second feed probe is connected with the second radiator; the radar chip is electrically connected with the first feed probe and the second feed probe. According to the technical scheme, the gap is formed between the main floor and the parasitic floor, and the main floor and the parasitic floor are electrically connected through the connecting resistor, so that the front-to-back ratio is greatly improved while the small floor size of the microstrip patch antenna is kept, the problem of front-to-back ratio deterioration caused by miniaturization is solved, the antenna performance can be improved, and the antenna cost is reduced. And therefore, the radar chip can be accurately positioned.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a radar sensor with an ultra-small floor and backward radiation suppression. Background Art

[0002] With the rapid development of IoT technology, miniaturized radar sensors are becoming a mainstream market requirement. However, as floor panels shrink, patch antennas' backward radiation increases. Excessive backward radiation often causes various electromagnetic interference issues. For example, in washing machines, the vibrations from the rotating drum can create interference, creating false targets. Excessive backward radiation can lead to radar misjudgments and false triggering. Conventional patch antennas have a front-to-back ratio of approximately 10dB, which is insufficient to meet the high front-to-back ratio requirements of radar sensors. Therefore, reducing the antenna's backward radiation intensity and improving its front-to-back ratio in the context of ultra-small floors are urgent technical challenges.

[0003] Currently, there are several approaches to improving the front-to-back ratio of antennas: 1) Using the Yagi-Uda antenna. For example, the Yagi-Uda antenna proposed in "SS Jehangir and MS Sharawi, "A Single Layer Semi-Ring Slot Yagi-Like MIMO Antenna System With High Front-to-Back Ratio," in IEEE Transactions on Antennas and Propagation, vol. 65, no. 2, pp. 937-942, February 2017" exhibits high front-to-back ratio performance. However, the antenna's side-beam characteristics make it difficult to adapt to wearable devices. 2) Using a cavity and reflector. For example, the paper "Zhang Long, Gao Steven, Qi Luo, et al. "Single-Feed Ultra-Wideband Circularly Polarized Antenna With Enhanced Front-to-Back Ratio," in IEEE Transactions on Antennas and Propagation, 2016, 64(1):355-360" proposes a circular cavity solution that blocks diffracted waves through vertical fins, thereby improving the front-to-back ratio. However, this antenna requires a higher profile and cannot be manufactured using planar processes. 3) Using serrated floor edge technology, such as that proposed in "G.H. Huff and J.T. Bernhard, "Improvements in the performance of microstrip antennas onfinite ground planes through ground plane edge serrations," in IEEE Microwave and Wireless Components Letters, vol. 12, no. 8, pp. 308-310, August 2002," can weaken the current intensity at the floor edge and suppress the diffraction of electromagnetic waves to the back side. However, the serrated edge itself requires a certain amount of space.4) Using magnetoelectric dipole technology, such as the magnetoelectric dipole solution proposed in the literature "L. Zhao et al.," Design of Wideband Dual-Polarized ME Dipole Antenna With Parasitic Elements and Improved Feed Structure," in IEEE Antennas and Wireless Propagation Letters, vol. 22, no. 1, pp. 174-178, Jan. 2023", which offsets backward radiation by constructing complementary magnetic current sources and current sources. However, this antenna technology cannot be directly applied to conventional patches.

[0004] In view of this, it is necessary to further improve the structure of the current antenna. Summary of the Invention

[0005] In order to solve at least one of the above technical problems, the main object of the present invention is to provide a radar sensor with an ultra-small floor and backward radiation suppression.

[0006] To achieve the above-mentioned object, the present invention adopts a technical solution: providing a radar sensor with an ultra-small floor and backward radiation suppression, comprising:

[0007] A floor comprising a main floor and at least one parasitic floor, wherein the main floor has a first surface and a second surface, the first surface and the second surface being arranged opposite to each other; the parasitic floor is arranged outside the main floor, and a gap is formed between the parasitic floor and the main floor;

[0008] a connecting resistor having a first end and a second end, the first end of the connecting resistor being electrically connected to the main ground plane, and the second end of the connecting resistor being electrically connected to the parasitic ground plane;

[0009] a first radiator and a second radiator, wherein the first radiator and the second radiator are separated and positioned above the first surface of the main floor;

[0010] a first feeding probe and a second feeding probe, wherein one end of the first feeding probe is connected to the first radiator, and the other end of the first feeding probe is sequentially passed through the first radiator and the first surface of the main floor and extends out of the second surface of the main floor; and one end of the second feeding probe is connected to the second radiator, and the other end of the second feeding probe is sequentially passed through the second radiator and the first surface of the main floor and extends out of the second surface of the main floor;

[0011] A radar chip is located below the second surface of the main floor, and the radar chip is electrically connected to one end of the first feeding probe and the second feeding probe extending out of the second surface of the main floor respectively.

[0012] The parasitic floor comprises a first parasitic floor and a second parasitic floor, the first parasitic floor and the second parasitic floor are respectively located on both sides of the main floor, and there is a gap between the first parasitic floor and the second parasitic floor and the main floor;

[0013] The connecting resistors include a first group of resistors and a second group of resistors, wherein the first end of the first group of resistors is electrically connected to the main floor, and the second end is electrically connected to the first parasitic floor; the first end of the second group of resistors is electrically connected to the main floor, and the second end is electrically connected to the second parasitic floor.

[0014] The first group of resistors and the second group of resistors each have at least two resistors, and the at least two resistors are evenly arranged between the main floor and the parasitic floor.

[0015] The resistance of the resistor is 10-1000Ω, the width of the gap is less than 0.1λ, and the package length of the resistor is less than the gap width, wherein λ is a vacuum wavelength.

[0016] The width of the floor is greater than or equal to 0.2λ and less than 0.5λ, and the length is greater than or equal to 0.75λ and less than 1.5λ, where λ is a vacuum wavelength.

[0017] Among them, it also includes a first dielectric layer, a second dielectric layer and a third dielectric layer arranged in sequence from top to bottom, the first dielectric layer and the second dielectric layer are stacked, the first radiator and the second radiator are respectively installed on the upper surface of the first dielectric layer, the main floor and the parasitic floor are both located between the second dielectric layer and the third dielectric layer, and the radar chip is installed on the lower surface of the third dielectric layer.

[0018] It also includes two ground vias, which pass through the first dielectric layer, the second dielectric layer and the third dielectric layer. One side of the main floor is connected to the hole wall of one ground via, and one side of the parasitic floor is connected to the hole wall of another ground via. The connection resistor is located between the two ground vias, and the two ends of the connection resistor are respectively electrically contacted with the hole walls of the two ground vias.

[0019] The connection resistor is located on the upper surface of the first dielectric layer, or the connection resistor is located on the lower surface of the third dielectric layer.

[0020] The parasitic floor comprises a first parasitic floor, a second parasitic floor, a third parasitic floor and a fourth parasitic floor, and the first parasitic floor, the second parasitic floor, the third parasitic floor and the fourth parasitic floor are respectively arranged on four sides of the main floor;

[0021] The connecting resistors include a first group of resistors, a second group of resistors, a third group of resistors and a fourth group of resistors. The first group of resistors is used to connect the first parasitic floor and the first side of the main floor. The second group of resistors is used to connect the second parasitic floor and the second side of the main floor. The third group of resistors is used to connect the third parasitic floor and the third side of the main floor. The fourth group of resistors is used to connect the fourth parasitic floor and the fourth side of the main floor.

[0022] The main floor is circular, the parasitic floor is arc-shaped, and the parasitic floor includes a first parasitic floor, a second parasitic floor, a third parasitic floor, and a fourth parasitic floor. The first parasitic floor, the second parasitic floor, the third parasitic floor, and the fourth parasitic floor are evenly arranged on the circumference of the main floor.

[0023] The connecting resistors include a first group of resistors, a second group of resistors, a third group of resistors and a fourth group of resistors. The first group of resistors is used to connect the first parasitic floor and the outside of the main floor. The second group of resistors is used to connect the second parasitic floor and the outside of the main floor. The third group of resistors is used to connect the third parasitic floor and the outside of the main floor. The fourth group of resistors is used to connect the fourth parasitic floor and the outside of the main floor.

[0024] The technical solution of the present invention utilizes a gap between the main floor and the parasitic floor, electrically connecting the two floors via a resistor. This allows the microstrip patch antenna to significantly improve its front-to-back ratio while maintaining a small floor size, addressing the issue of reduced front-to-back ratio due to miniaturization and improving antenna performance. The first and second radiators are capable of transmitting and receiving signals. When the signal encounters a human subject, it is reflected, creating a Doppler effect between the transmitted and reflected signals. The second radiator receives the radio frequency signal reflected by the subject and transmits it to a radar chip, which analyzes the reflected signal to accurately determine the subject's location. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0026] Figure 1 Schematic diagram of the structure of an antenna in a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention;

[0027] Figure 2 1. A schematic diagram of an antenna in a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention;

[0028] Figure 3 Schematic diagram of an antenna structure without a loaded connection resistor in a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention;

[0029] Figure 4 Schematic diagram of a radar chip in a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention;

[0030] Figure 5 Schematic diagram of the overall structure of a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention;

[0031] Figure 6 FIG1 is a top view of a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention;

[0032] Figure 7 A bottom view of a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention;

[0033] Figure 8 Schematic diagram of the structure of a dual-polarized antenna in a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention;

[0034] Figure 9 Schematic diagram of the structure of a dual-polarized antenna with a circular floor in a radar sensor with an ultra-small floor and backward radiation suppression according to one embodiment of the present invention;

[0035] Figure 10 yes Figure 3 Floor current distribution diagram of the antenna shown;

[0036] Figure 11 yes Figure 1 Floor current distribution diagram of the antenna shown;

[0037] Figure 12 yes Figure 1 Reflection coefficient curve of the antenna shown;

[0038] Figure 13 yes Figure 1 、 Figure 3 The E-plane radiation pattern of the antenna shown at 5.8 GHz.

[0039] In the picture:

[0040] 100, main floor; 101, first parasitic floor; 102, second parasitic floor; 103, floor body; 11, connection resistor; 121, first radiator; 122, second radiator; 131, first feed probe; 132, second feed probe; 14, ground via; 15, component trace; 16, radar chip;

[0041] 2. Dielectric layer; 3. First dielectric layer; 4. Second dielectric layer; 5. Third dielectric layer;

[0042] 200, main floor; 201, parasitic floor; 210, radiator; 211, feed probe;

[0043] 300, main floor; 301, parasitic floor; 310, radiator; 311, feeding probe.

[0044] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] It should be noted that the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0047] Unlike related art technologies that struggle to reduce the antenna's backward radiation intensity and improve its front-to-back ratio in ultra-small floor panels, the present invention provides a radar sensor with an ultra-small floor panel and backward radiation suppression. By connecting resistors to load the gaps between the floor panels, this method reduces the antenna's backward radiation intensity and improves its front-to-back ratio in ultra-small floor panels. The detailed structure of this radar sensor with an ultra-small floor panel and backward radiation suppression is described in the following embodiments.

[0048] Please refer to Figures 1 to 7 , Figure 1 Schematic diagram of the structure of an antenna in a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention; Figure 2 1. A schematic diagram of an antenna in a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention; Figure 3 Schematic diagram of an antenna structure without a loaded connection resistor in a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention;

[0049] Figure 4 Schematic diagram of a radar chip in a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention; Figure 5 Schematic diagram of the overall structure of a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention; Figure 6 FIG1 is a top view of a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention; Figure 7 This is a bottom view of a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention. In this embodiment of the present invention, the radar sensor with an ultra-small floor and backward radiation suppression includes:

[0050] A floor, comprising a main floor 100 and at least one parasitic floor (101, 102), wherein the main floor 100 has a first surface and a second surface, the first surface and the second surface being arranged opposite to each other; the parasitic floor (101, 102) being arranged outside the main floor 100, and a gap being formed between the parasitic floor (101, 102) and the main floor 100;

[0051] A connecting resistor 11, the connecting resistor 11 having a first end and a second end, the first end of the connecting resistor 11 being electrically connected to the main floor 100, and the second end of the connecting resistor 11 being electrically connected to the parasitic floor (101, 102);

[0052] A first radiator 121 and a second radiator 122 , wherein the first radiator 121 and the second radiator 122 are separated and located above the first surface of the main floor 100 ;

[0053] A first feeding probe 131 and a second feeding probe 132, wherein one end of the first feeding probe 131 is connected to the first radiator 121, and the other end thereof sequentially passes through the first radiator 121 and the first surface of the main floor 100 and extends out of the second surface of the main floor 100; one end of the second feeding probe 132 is connected to the second radiator 122, and the other end thereof sequentially passes through the second radiator 122 and the first surface of the main floor 100 and extends out of the second surface of the main floor 100;

[0054] The radar chip 16 is located below the second surface of the main floor 100 , and is electrically connected to one end of the first feeding probe 131 and the second feeding probe 132 extending out of the second surface of the main floor 100 .

[0055] In this embodiment, the main floor 100 is a rectangular floor, and the parasitic floors (101, 102) are strip-shaped floors. The main floor 100 is larger than the parasitic floors (101, 102). The parasitic floors (101, 102) are located on both sides of the main floor 100, which can be the left and right sides or the top and bottom sides. A narrow gap is provided between the main floor 100 and the parasitic floors (101, 102). The gap is used to separate the main floor 100 and the parasitic floors (101, 102) to prevent direct metal connection between the two. The number of parasitic floors (101, 102) can be flexibly selected according to actual requirements, and can be two or four. The main floor 100 and the parasitic floors (101, 102) are electrically connected via a connecting resistor 11. By connecting the resistor 11 and the gap structure, the antenna's backward radiation intensity can be reduced in the context of an ultra-small floor, thereby improving the antenna's front-to-back ratio. The side lengths of the first radiator 121 and the second radiator 122 are less than half the free-space wavelength λ within the operating frequency band, where λ is the free-space wavelength, also known as the vacuum wavelength. The first radiator 121 and the second radiator 122 can be rectangular, or other shapes are possible. The E-plane and H-plane represent the length and width of the antenna, respectively. The E-plane dimension is less than 0.5λ, the length of the antenna's E-plane is greater than the width of the H-plane, the ratio of the antenna's E-plane length to the H-plane width is greater than 1, and the spacing between the antenna radiators is less than 0.5λ. One of the first radiator 121 and the second radiator 122 is used for signal transmission, and the other is used for signal reception. The transmitting pin Tx of the radar chip 16 can be connected to the first radiator 121 through the first feeding probe 131, and the receiving pin Rx can be connected to the second radiator 122 through the second feeding probe 132. At this time, the first radiator 121 is a transmitting antenna and the second radiator 122 is a receiving antenna. The radar chip 16 can control the transmission of the signal and the reception of the reflected signal. When the signal encounters the human body to be measured in the environment, signal reflection will occur, and the transmitted signal and the reflected signal will produce a Doppler effect. The second radiator 122 receives the radio frequency signal reflected by the human body to be measured and transmits it to the radar chip 16. By analyzing the reflected signal by the radar chip 16, the presence position of the human body can be accurately determined, which is convenient for subsequent intelligent control.

[0056] Furthermore, when the first and second feeding probes 131, 132 pass through the main floor panel 100, they each avoid contact with the main floor panel 100 to prevent metallic contact. Specifically, the main floor panel 100 includes corresponding avoidance holes for the first and second feeding probes 131, 132, through which the first and second feeding probes 131, 132 extend out of the main floor panel 100. The avoidance holes are larger than the diameters of the first and second feeding probes 131, 132, or are filled with insulating adhesive, for example, to achieve electrical isolation.

[0057] When no connection resistor 11 is loaded, the main floor 100 and the parasitic floor (101, 102) together form the floor body 103. A dielectric layer 2 is disposed between the main floor 100 and the first radiator 121 and the second radiator 122. The first radiator 121 and the second radiator 122 are located on the same plane and are both located on the upper surface of the dielectric layer 2. The main floor 100 and the parasitic floor (101, 102) are located on the lower surface of the dielectric layer 2.

[0058] In a specific embodiment, the parasitic floor (101, 102) includes a first parasitic floor 101 and a second parasitic floor 102, wherein the first parasitic floor 101 and the second parasitic floor 102 are respectively located on both sides of the main floor 100, and gaps are respectively formed between the first parasitic floor 101 and the second parasitic floor 102 and the main floor 100;

[0059] The connecting resistor 11 includes a first group of resistors and a second group of resistors. The first end of the first group of resistors is electrically connected to the main floor 100, and the second end is electrically connected to the first parasitic floor 101; the first end of the second group of resistors is electrically connected to the main floor 100, and the second end is electrically connected to the second parasitic floor 102.

[0060] Specifically, a first parasitic floor panel 101 and a second parasitic floor panel 102 are mounted on the wide sides of the main floor panel 100, respectively. The shapes of the first and second parasitic floors 101, 102 can be strip-shaped or irregular, depending on the structural design requirements. Correspondingly, the connecting resistors 11 include a first set of resistors and a second set of resistors. The first set of resistors connects the first parasitic floor panel 101 to the main floor panel 100, while the second set of resistors connects the second parasitic floor panel 102 to the main floor panel 100.

[0061] Furthermore, the first resistor group and the second resistor group each include at least two resistors, and the at least two resistors are evenly arranged between the main floor 100 and the parasitic floor (101, 102). The at least two resistors are evenly distributed to ensure connection reliability. The number of resistors can be flexibly set according to actual needs and is not limited here.

[0062] Specifically, the resistance of the resistor is 10-1000Ω, the width of the gap is less than 0.1λ, and the package length of the resistor is less than the gap width, where λ is the vacuum wavelength. The resistor is preferably 82Ω, and other resistance values of the resistor are all feasible solutions. The width of the gap is less than 0.1λ, and a ground via can be set at the gap. The package size of the resistor can be smaller than the gap. The resistor mainly connects the main floor 100 and the parasitic floor (101, 102) to achieve electrical connection between the two. The floor in this solution is an ultra-small floor, the width of the floor is greater than or equal to 0.2λ and less than 0.5λ, and the length is greater than or equal to 0.75λ and less than 1.5λ, where λ is the vacuum wavelength.

[0063] In a specific embodiment, the system further includes a first dielectric layer 3, a second dielectric layer 4, and a third dielectric layer 5, arranged sequentially from top to bottom. The first dielectric layer 3 and the second dielectric layer 4 are stacked. The first radiator 121 and the second radiator 122 are respectively mounted on the upper surface of the first dielectric layer 3. The main floor 100 and the parasitic floors (101, 102) are located between the second dielectric layer 4 and the third dielectric layer 5. The radar chip 16 is mounted on the lower surface of the third dielectric layer 5. The areas of the first dielectric layer 3, the second dielectric layer 4, and the third dielectric layer 5 are slightly larger than the sum of the areas of the main floor 100 and the parasitic floors (101, 102). The first dielectric layer 3 and the second dielectric layer 4 can separate the first radiator 121 and the second radiator 122 from the main floor 100 and the parasitic floors (101, 102). The third dielectric layer 5 can separate the main floor 100 from the radar chip 16. The third dielectric layer 5 can connect various components via component traces 15.

[0064] Furthermore, the present invention further comprises two ground vias 14, wherein the ground vias 14 penetrate the first dielectric layer 3, the second dielectric layer 4, and the third dielectric layer 5. One side of the main floor 100 is connected to the hole wall of one ground via 14, and one side of the parasitic floor (101, 102) is connected to the hole wall of the other ground via 14. The hole walls of the two ground vias 14 respectively connect the main floor 100 and the parasitic floor (101, 102). The connecting resistor 11 is located between the two ground vias 14, and the two ends of the connecting resistor 11 are respectively in electrical contact with the hole walls of the two ground vias 14. Four ground vias 14 can be provided between the main floor 100 and the parasitic floor (101, 102), two of which are located on one side of the main floor 100, and the other two ground vias 14 are located on one side of the parasitic floor (101, 102). In this case, the main floor 100 and the parasitic floor (101, 102) can be connected via two resistors. It is understandable that the hole wall of the grounding via 14 is made of conductive metal, or the hole wall of the grounding via 14 can be filled with conductive material.

[0065] Specifically, the connection resistor 11 is located on the upper surface of the first dielectric layer 3, or the connection resistor 11 is located on the lower surface of the third dielectric layer 5. Since the ground via 14 passes through the first dielectric layer 3, the second dielectric layer 4, and the third dielectric layer 5, the connection resistor 11 can be located at the entrance or exit of the ground via 14. This can be flexibly selected according to processing and assembly requirements and is not limited here.

[0066] Please refer to Figure 8 , Figure 8 This is a schematic diagram of the structure of a dual-polarized antenna in a radar sensor with an ultra-small floor and backward radiation suppression according to an embodiment of the present invention. In one embodiment, the parasitic floor 201 includes a first parasitic floor, a second parasitic floor, a third parasitic floor, and a fourth parasitic floor, which are respectively disposed on four sides of the main floor 200.

[0067] The connecting resistors include a first group of resistors, a second group of resistors, a third group of resistors, and a fourth group of resistors. The first group of resistors is used to connect the first parasitic floor and the first side of the main floor 200. The second group of resistors is used to connect the second parasitic floor and the second side of the main floor 200. The third group of resistors is used to connect the third parasitic floor and the third side of the main floor 200. The fourth group of resistors is used to connect the fourth parasitic floor and the fourth side of the main floor 200.

[0068] Specifically, this dual-polarized antenna has only one square radiator 210. Both the main floor 200 and the parasitic floor 201 are square, with the main floor 200 being square. The square radiator 210 is electrically connected to the radar chip 16 via a feed probe 211. This radiator 210 can simultaneously transmit and receive signals. The first and second resistor groups are symmetrically arranged, and the third and fourth resistor groups are symmetrically arranged.

[0069] Please refer to Figure 9 , Figure 9 This figure illustrates the structure of a dual-polarized antenna with a circular floor in a radar sensor with an ultra-small floor and back-radiation suppression, according to an embodiment of the present invention. In one embodiment, the main floor 300 is circular, and the parasitic floor 301 is arc-shaped. The parasitic floor 301 includes a first parasitic floor, a second parasitic floor, a third parasitic floor, and a fourth parasitic floor. The first, second, third, and fourth parasitic floors are evenly distributed around the main floor 300.

[0070] The connecting resistors include a first group of resistors, a second group of resistors, a third group of resistors and a fourth group of resistors. The first group of resistors is used to connect the first parasitic floor and the outside of the main floor 300, the second group of resistors is used to connect the second parasitic floor and the outside of the main floor 300, the third group of resistors is used to connect the third parasitic floor and the outside of the main floor 300, and the fourth group of resistors is used to connect the fourth parasitic floor and the outside of the main floor 300.

[0071] Specifically, this dual-polarized antenna has only one circular radiator 310. The main base plate 300 is circular, and the parasitic base plate 301 is arc-shaped. The circular radiator 310 is electrically connected to the radar chip 16 via a feed probe 311. This radiator 310 can simultaneously transmit and receive signals. The first and second resistor groups are symmetrically arranged, and the third and fourth resistor groups are symmetrically arranged.

[0072] Please refer to Figure 1 、 Figure 3 、 Figure 10-13 .in, Figure 10 yes Figure 3 Floor current distribution diagram of the antenna shown; Figure 11 yes Figure 1 Floor current distribution diagram of the antenna shown; Figure 12 yes Figure 1 Reflection coefficient curve of the antenna shown; Figure 13 yes Figure 1 、 Figure 3 The E-plane radiation pattern of the antenna shown at 5.8GHz. Figure 10 and Figure 11 By comparing simulation results, we compared the changes in the back-side current distribution of the small floor patch antenna before and after loading with resistors and floor gaps. In the figure, the size of the arrow represents the intensity of the current. The larger the current, the larger the arrow. Due to the absorption effect of the lumped resistor, the surface current on the back side of the ground is reduced to a certain extent after the loading technology of the floor gap with resistors is used, which helps to suppress the back radiation. It can be seen that compared with Figure 10 Compared with the current distribution of conventional patch antenna, Figure 11 The size of the arrow on the back of the floor of the antenna loaded with resistive floor gaps becomes smaller, that is, the current intensity is reduced to a certain extent, indicating that the backward radiation is suppressed. Figure 12 It can be seen that the reflection of the patch antenna at 5.8GHz is about -12dB, which has a good reflection effect. Figure 13 It can be seen that at theta = ±150°, the front-to-back ratio of the patch antenna based on the loading technology is within that of the unloaded patch antenna, and the front-to-back ratio of the patch antenna is greatly improved.

[0073] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made by using the contents of the present invention description and drawings under the technical solution of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A radar sensor with ultra-small floor and back radiation suppression, characterized in that: include: A floor, comprising a main floor and at least one parasitic floor, wherein the main floor has a first surface and a second surface, wherein the first surface is disposed opposite to the second surface; The parasitic floor is arranged on the outside of the main floor, and a gap is formed between the parasitic floor and the main floor; a connecting resistor having a first end and a second end, the first end of the connecting resistor being electrically connected to the main ground plane, and the second end of the connecting resistor being electrically connected to the parasitic ground plane; a first radiator and a second radiator, wherein the first radiator and the second radiator are separated and positioned above the first surface of the main floor; a first feeding probe and a second feeding probe, wherein one end of the first feeding probe is connected to the first radiator, and the other end of the first feeding probe is sequentially passed through the first radiator and the first surface of the main floor and extends out of the second surface of the main floor; and one end of the second feeding probe is connected to the second radiator, and the other end of the second feeding probe is sequentially passed through the second radiator and the first surface of the main floor and extends out of the second surface of the main floor; A radar chip is located below the second surface of the main floor, and the radar chip is electrically connected to one end of the first feeding probe and the second feeding probe extending out of the second surface of the main floor respectively.

2. The radar sensor with ultra-small floor and backward radiation suppression according to claim 1, characterized in that: The parasitic floor comprises a first parasitic floor and a second parasitic floor, wherein the first parasitic floor and the second parasitic floor are respectively located on both sides of the main floor, and gaps are respectively formed between the first parasitic floor and the second parasitic floor and the main floor; The connection resistors include a first group of resistors and a second group of resistors, wherein a first end of the first group of resistors is electrically connected to the main ground plane, and a second end thereof is electrically connected to the first parasitic ground plane; A first end of the second resistor group is electrically connected to the main ground plane, and a second end of the second resistor group is electrically connected to the second parasitic ground plane.

3. The radar sensor with ultra-small floor and backward radiation suppression according to claim 2, characterized in that: The first group of resistors and the second group of resistors each have at least two resistors, and the at least two resistors are evenly arranged between the main floor and the parasitic floor.

4. The radar sensor with ultra-small floor and backward radiation suppression according to claim 3, characterized in that: The resistance of the resistor is 10-1000Ω, the width of the gap is less than 0.1λ, and the package length of the resistor is less than the gap width, wherein λ is a vacuum wavelength.

5. The radar sensor with ultra-small floor and backward radiation suppression according to claim 1, characterized in that: The width of the floor is greater than or equal to 0.2λ and less than 0.5λ, and the length is greater than or equal to 0.75λ and less than 1.5λ, wherein λ is a vacuum wavelength.

6. The radar sensor with ultra-small floor and backward radiation suppression according to claim 1, characterized in that: It also includes a first dielectric layer, a second dielectric layer and a third dielectric layer arranged in sequence from top to bottom, the first dielectric layer and the second dielectric layer are stacked, the first radiator and the second radiator are respectively installed on the upper surface of the first dielectric layer, the main floor and the parasitic floor are both located between the second dielectric layer and the third dielectric layer, and the radar chip is installed on the lower surface of the third dielectric layer.

7. The radar sensor with ultra-small floor and backward radiation suppression according to claim 6, characterized in that: It also includes two ground vias, which pass through the first dielectric layer, the second dielectric layer and the third dielectric layer. One side of the main floor is connected to the hole wall of one ground via, and one side of the parasitic floor is connected to the hole wall of the other ground via. The connection resistor is located between the two ground vias, and the two ends of the connection resistor are respectively electrically contacted with the hole walls of the two ground vias.

8. The radar sensor with ultra-small floor and backward radiation suppression according to claim 7, characterized in that: The connection resistor is located on the upper surface of the first dielectric layer, or the connection resistor is located on the lower surface of the third dielectric layer.

9. The radar sensor with ultra-small floor and backward radiation suppression according to claim 1, characterized in that: The parasitic floor comprises a first parasitic floor, a second parasitic floor, a third parasitic floor and a fourth parasitic floor, wherein the first parasitic floor, the second parasitic floor, the third parasitic floor and the fourth parasitic floor are respectively arranged on four sides of the main floor; The connecting resistors include a first group of resistors, a second group of resistors, a third group of resistors and a fourth group of resistors. The first group of resistors is used to connect the first parasitic floor and the first side of the main floor. The second group of resistors is used to connect the second parasitic floor and the second side of the main floor. The third group of resistors is used to connect the third parasitic floor and the third side of the main floor. The fourth group of resistors is used to connect the fourth parasitic floor and the fourth side of the main floor.

10. The radar sensor with ultra-small floor and backward radiation suppression according to claim 1, characterized in that: The main floor is circular, the parasitic floor is arc-shaped, and the parasitic floor includes a first parasitic floor, a second parasitic floor, a third parasitic floor, and a fourth parasitic floor. The first parasitic floor, the second parasitic floor, the third parasitic floor, and the fourth parasitic floor are evenly arranged on the circumference of the main floor. The connecting resistors include a first group of resistors, a second group of resistors, a third group of resistors and a fourth group of resistors. The first group of resistors is used to connect the first parasitic floor and the outside of the main floor. The second group of resistors is used to connect the second parasitic floor and the outside of the main floor. The third group of resistors is used to connect the third parasitic floor and the outside of the main floor. The fourth group of resistors is used to connect the fourth parasitic floor and the outside of the main floor.

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