Circularly Polarized Patch Antenna Array Structure and System

Abstract

The present invention provides a circularly polarized patch antenna array structure and system, which includes a plurality of antenna array units evenly distributed at circumferential intervals, a micro coaxial transmission line, and a metal floor. The antenna array unit includes a micro coaxial feeding structure, a metal support column, and a metal disk. One end of the metal support column is connected to the metal floor, and the other end of the metal support column is connected to the metal disk. The micro coaxial feeding structure includes an outer feeding part and an inner feeding part disposed in the outer feeding part. The inner feeding part has two feeding probes extending out of the outer feeding part. Both feeding probes extend between the metal disk and the metal floor, and one end of the feeding probe is disposed close to the metal column. The two feeding probes are perpendicularly arranged, and the phase difference output by the two feeding probes is 90 degrees. The antenna array unit and the micro coaxial transmission line are both of micro coaxial structures, with small sizes, low profile, and compact structures. Moreover, low transmission loss is achieved, thereby improving the antenna gain.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic waves, and more specifically, relates to a circularly polarized patch antenna array structure and system. Background Art

[0002] An antenna array usually includes a large number of radiation elements and requires a feed network with low loss. First, for the feed elements, a metal waveguide has low transmission loss and can achieve high gain characteristics of the antenna. However, its volume is large and it is not suitable for millimeter-wave planar circuit integration. A microstrip line has advantages such as a compact structure and simple integration, so it is widely used in the feed network of antennas. But a microstrip line usually has a high dielectric loss, especially when designing a large array. A substrate integrated waveguide, as a planar waveguide transmission line, has been widely used in the design of millimeter-wave antenna arrays due to its advantages such as low loss and high cost-effectiveness. The above-mentioned antenna forms have a high profile and are not conducive to high integration. Second, for the feed structure, a circularly polarized antenna array can be composed of a feed network with equal-phase uniform distribution and antenna elements. For a feed network with equal-phase uniform distribution, the bandwidth of the antenna array is usually narrow. Summary of the Invention

[0003] The purpose of the embodiments of the present invention is to provide a circularly polarized patch antenna array structure and system to solve the technical problems of high profile, large volume, and narrow bandwidth existing in the prior art.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: to provide a circularly polarized patch antenna array structure, including:

[0005] A plurality of antenna array units evenly spaced circumferentially, a micro coaxial transmission line connecting each of the antenna array units, and a metal floor. The antenna array units and the micro coaxial transmission line are both disposed on the metal floor. Each of the antenna array units is arranged to rotate a predetermined angle in sequence along the arrangement direction, and the product of the predetermined angle and the number of the antenna array units is 360 degrees.

[0006] The antenna array unit includes a micro coaxial feed structure, a metal support column, and a metal disk. One end of the metal support column is connected to the metal floor, and the other end of the metal support column is connected to the metal disk. The micro coaxial feed structure includes an outer feed part and an inner feed part disposed in the outer feed part. The inner feed part has two feed probes extending out of the outer feed part. Both of the feed probes extend between the metal disk and the metal floor, and one end of the feed probe is disposed close to the metal support column. The two feed probes are perpendicularly arranged, and the phase difference between the outputs of the two feed probes is 90 degrees.

[0007] The micro coaxial transmission line includes a transmission outer shell and a transmission inner core disposed inside the transmission outer shell. The transmission outer shell is connected to the external feeding part, and the transmission inner core is connected to the internal feeding part.

[0008] Optionally, the micro coaxial feeding structure has a first feeding input end and two first output ends. The transmission distance between the first feeding input end and each of the first output ends is a first transmission distance, and the difference between the two first transmission distances is 1 / 4 wavelength corresponding to the operating frequency.

[0009] Optionally, the micro coaxial feeding structure includes a main feeding structure, a first feeding section, a second feeding section, and a third feeding section. The first feeding section, the second feeding section, and the third feeding section are sequentially and perpendicularly connected. One end of the main feeding structure is the first feeding input end, and the other end is connected to the second feeding section. One end of the first feeding section away from the second feeding section and one end of the third feeding section away from the second feeding section are both the first output ends. The connection point between the main feeding structure and the second feeding section is set as a reference point. The distance from the reference point to one of the first output ends is one branch feeding structure, and the distance from the reference point to the other first output end is the other branch feeding structure.

[0010] Optionally, the resistance of the internal feeding parts of the two branch feeding structures is 50Ω. The internal feeding part of the main feeding structure includes a first internal feeding section and a second internal feeding section connected to each other. One end of the second internal feeding section away from the first internal feeding section is located at the reference point. The cross-sectional area of the first internal feeding section is smaller than that of the second internal feeding section. The resistance of the first internal feeding section is 50Ω, and the resistance of the second internal feeding section is 35Ω.

[0011] Optionally, a dielectric support structure is provided inside the transmission outer shell, and the transmission inner core is located on the dielectric support structure.

[0012] Optionally, the number of the antenna array units is four, and the phase difference between two adjacent antenna array units is 90 degrees.

[0013] Optionally, the micro coaxial transmission line has a second feeding input end and four second output ends. The transmission distance between the second feeding input end and each of the second output ends is a second transmission distance, and the difference between the second transmission distances between two adjacent second output ends is 1 / 4 wavelength corresponding to the operating frequency.

[0014] Optionally, a feeding hole is provided at the second feeding input end of the transmission outer shell, and the transmission inner core has a stepped structure extending towards the feeding hole at the second feeding input end.

[0015] Optionally, the operating frequency of the circularly polarized patch antenna array structure is from 57 GHz to 66 GHz.

[0016] The present invention also provides a circularly polarized patch antenna array system, comprising a plurality of the above-mentioned circularly polarized patch antenna array structures.

[0017] The beneficial effects of the circularly polarized patch antenna array structure and system provided by the present invention are as follows: Compared with the prior art, the circularly polarized patch antenna array structure of the present invention includes a plurality of antenna array units and micro coaxial transmission lines connecting the respective antenna array units. The plurality of antenna array units are sequentially rotated by a predetermined angle along the arrangement direction to implement a sequential rotation feeding structure, thereby improving the bandwidth of the antenna array structure. Both the antenna array units and the micro coaxial transmission lines are of micro coaxial structures. The transmission size of the micro coaxial structure is small. After the sequential rotation feeding structure is formed by the plurality of antenna array units, the array structure can also be maintained in a small volume, having the characteristics of low profile and compact structure, and also achieving low transmission loss, thereby improving the antenna gain. The antenna array unit includes a micro coaxial feeding structure, a metal support column, and a metal disk. The phase difference between the two feeding probes in the micro coaxial feeding structure is 90 degrees, realizing the circular polarization of the antenna array unit. By extending the two feeding probes to be close to the metal support column and located between the metal floor and the metal disk, the transmission loss can be reduced and the antenna gain can be improved. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 The front view of the circularly polarized patch antenna array structure provided by the embodiment of the present invention;

[0020] Figure 2 The front view of the antenna array unit provided by the embodiment of the present invention;

[0021] Figure 3 The side view of the antenna array unit provided by the embodiment of the present invention;

[0022] Figure 4 The three-dimensional structure diagram of the antenna array unit provided by the embodiment of the present invention (the metal disk and the metal support column are not shown);

[0023] Figure 5 For Figure 2 The simulation curve diagram of the reflection coefficient and gain of the antenna array unit in

[0024] Figure 6 is Figure 2 the simulation curve graph of the axial ratio of the antenna array unit in

[0025] Figure 7 is Figure 2 the simulation current distribution graph of the antenna array unit at 60 GHz in

[0026] Figure 8 is Figure 1 the simulation curve graph of the reflection coefficient and gain of the circularly polarized patch antenna array structure in

[0027] Figure 9 is Figure 1 the simulation curve graph of the axial ratio of the circularly polarized patch antenna array structure in

[0028] Figure 10 is Figure 1 the simulation curve graph of the radiation efficiency of the circularly polarized patch antenna array structure in

[0029] Figure 11 is the three-dimensional structure diagram of the micro coaxial feeding structure provided by the embodiment of the present invention;

[0030] Figure 12 is the front view of the inner feeding part provided by the embodiment of the present invention;

[0031] Figure 13 is Figure 11 the simulation curve graph of the reflection coefficient of the micro coaxial feeding structure in

[0032] Figure 14 is Figure 11 the phase difference curve graph of the two first output ends of the micro coaxial feeding structure in

[0033] Figure 15 is the partial three-dimensional structure diagram of the micro coaxial transmission line provided by the embodiment of the present invention;

[0034] Figure 16 is the side view of the micro coaxial transmission line provided by the embodiment of the present invention.

[0035] Among them, each reference numeral in the figure:

[0036] 10 - antenna array unit; 11 - micro coaxial feeding structure; 1101 - first feeding input end; 1102 - first output end; 111 - external feeding part; 112 - internal feeding part; 113 - main feeding structure; 1131 - first internal feeding section; 1132 - second internal feeding section; 114 - first feeding section; 115 - second feeding section; 116 - third feeding section; 117 - reference point; 118 - branch feeding structure; 12 - metal disk; 13 - metal support column; 14 - feeding probe;

[0037] 20 - micro - coaxial transmission line; 21 - transmission housing; 211 - feed hole; 22 - transmission inner core; 221 - stepped structure; 23 - dielectric support structure; 24 - second feed input end;

[0038] 30 - metal floor; 40 - process hole. Specific embodiments

[0039] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0040] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0041] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and 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 cannot be understood as a limitation to the present invention.

[0042] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0043] Antenna arrays usually contain a large number of radiating elements and require a feed network with low losses. First, for the feed elements, metal waveguides have low transmission losses and can achieve high-gain characteristics of the antenna. However, their large volume makes them unsuitable for millimeter-wave planar circuit integration. Microstrip lines have the advantages of compact structure and simple integration, so they are widely used in the feed network of antennas. However, microstrip lines usually have high dielectric losses, especially when designing large arrays. Substrate integrated waveguide, as a planar waveguide transmission line, has been widely used in the design of millimeter-wave antenna arrays due to its low losses and high cost-effectiveness. The above antenna forms have a high profile, which is not conducive to high integration. Second, for the feed structure, a circularly polarized antenna array can be composed of a feed network with equal-phase and uniform distribution and antenna elements. For a feed network with equal-phase and uniform distribution, the bandwidth of the antenna array is usually narrow.

[0044] In view of the above problems, the present application proposes a circularly polarized patch antenna array structure excited by a microcoaxial transmission line 20, which includes a plurality of antenna array units 10, a microcoaxial transmission line 20, and a metal floor 30. The plurality of antenna array units 10 are circumferentially and evenly spaced, and are sequentially rotated by a predetermined angle along their arrangement direction to achieve sequential rotation feeding, improving the bandwidth of the antenna array structure. By setting the feed structure and transmission line of the antenna array unit 10 to a microcoaxial structure, the volume of the antenna array structure can be reduced, and the structure is more compact and has a lower profile. The phase difference between the two feed probes 14 of the microcoaxial feed structure 11 is 90 degrees, realizing circular polarization of the antenna array unit 10. The two feed probes 14 extend to be close to the metal support post 13 and are located between the metal disc 12 and the metal floor 30, so as to improve the gain of the antenna array unit 10. This circularly polarized patch antenna array structure has wide bandwidth, high gain, high radiation efficiency, and compact size, and can solve the technical problems of large transmission losses and narrow AR bandwidth in the related art.

[0045] Now, the circularly polarized patch antenna array structure provided by the embodiments of the present invention will be described.

[0046] Please refer to Figures 1 to 4 , the circularly polarized patch antenna array structure includes a plurality of antenna array units 10 that are circumferentially and evenly spaced, a microcoaxial transmission line 20 connecting each antenna array unit 10, and a metal floor 30. The antenna array units 10 and the microcoaxial transmission line 20 are both disposed on the metal floor 30. Each antenna array unit 10 is sequentially rotated by a predetermined angle along the arrangement direction, and the product of the predetermined angle and the number of antenna array units 10 is 360 degrees.

[0047] The antenna array unit 10 includes a micro coaxial feeding structure 11, a metal support column 13, and a metal disk 12. One end of the metal support column 13 is connected to the metal floor 30, and the other end of the metal support column 13 is connected to the metal disk 12. The micro coaxial feeding structure 11 includes an outer feeding part 111 and an inner feeding part 112 disposed in the outer feeding part 111. The inner feeding part 112 has two feeding probes 14 extending out of the outer feeding part 111. Both of the two feeding probes 14 extend between the metal disk 12 and the metal floor 30, and one end of each feeding probe 14 is disposed close to the metal support column 13. The two feeding probes 14 are perpendicularly arranged, and the phase difference between the outputs of the two feeding probes 14 is 90 degrees.

[0048] The micro coaxial transmission line 20 includes a transmission outer shell 21 and a transmission inner core 22 disposed inside the transmission outer shell 21. The transmission outer shell 21 is connected to the outer feeding part 111, and the transmission inner core 22 is connected to the inner feeding part 112.

[0049] The antenna array unit 10 is one of the units in the array structure. Generally, the array structure is formed by a plurality of antenna array units 10 according to a certain arrangement rule. The plurality of antenna array units 10 are circumferentially evenly spaced. It can be understood that the plurality of antenna array units 10 are distributed around a central point, and the magnitudes of the central angles corresponding to any two adjacent antenna array units 10 are the same. For example, when the number of antenna array units 10 is four, the central angle corresponding to any two adjacent antenna array units 10 is 90 degrees; when the number of antenna array units 10 is six, the central angle corresponding to any two adjacent antenna array units 10 is 60 degrees. Each antenna array unit 10 is sequentially rotated by a predetermined angle along the arrangement direction. It can be understood that the "arrangement direction" is the circumferential direction, which can be the clockwise direction or the counterclockwise direction. For example, in the clockwise direction, the positions where each antenna array unit 10 is located are the first position, the second position... the Nth position. The antenna array unit 10 at the second position is formed by rotating the antenna array unit 10 at the first position clockwise by a predetermined angle, and the antenna array unit 10 at the third position is formed by rotating the antenna array unit 10 at the second position clockwise by a predetermined angle, and so on. In this way, an orderly rotation feeding structure can be formed by arranging each antenna array unit 10, which can not only improve the bandwidth of the antenna array structure but also achieve circular polarization.

[0050] The antenna array unit 10 includes a micro coaxial feeding structure 11, a metal support column 13, and a metal disc 12. When the metal support column 13 and the metal disc 12 are both projected onto the metal floor 30, the metal support column 13 is located within the projection area of the metal disc 12, and the cross-sectional area of the metal support column 13 is smaller than the area of the metal disc 12. The combination of the metal support column 13 and the metal disc 12 is similar to an "umbrella-shaped" or "mushroom-shaped" structure. The micro coaxial feeding structure 11 includes an outer feeding part 111 and an inner feeding part 112. The inner feeding part 112 is suspended within the outer feeding part 111, and there is no other metal structure between them. The inner feeding part 112 has two feeding probes 14 arranged perpendicular to each other. The feeding probes 14 are exposed outside the outer feeding part 111, and the feeding probes 14 extend close to the metal support column 13. The feeding probes 14 do not contact the metal support column 13, and the feeding probes 14 are located between the metal disc 12 and the metal floor 30. By designing the antenna array unit 10 in this way, the gain of the antenna array unit 10 can be increased, and the radiation efficiency can be improved.

[0051] The micro coaxial transmission line 20 is used to connect each antenna array unit 10. The micro coaxial transmission line 20 can transmit signals to each antenna array unit 10 and feed each antenna array unit 10. The micro coaxial transmission line 20 includes a transmission outer shell 21 and a transmission inner core 22. Both the transmission outer shell 21 and the transmission inner core 22 are metal structures. The transmission outer shell 21 is connected and conducted with the outer feeding part 111, and the transmission inner core 22 is connected and conducted with the inner feeding part 112. When feeding the micro coaxial transmission line 20, electromagnetic waves are propagated to each antenna array unit 10 through the micro coaxial transmission line 20. The micro coaxial transmission line 20 can reduce the volume of the antenna array structure, has low transmission loss, and also provides good isolation between adjacent passive devices due to its fully shielded structure.

[0052] The circularly polarized patch antenna array structure in the above embodiments includes a plurality of antenna array units 10 and a micro coaxial transmission line 20 connecting each antenna array unit 10. The sequential rotation feeding structure is realized by arranging the plurality of antenna array units 10 at a predetermined angle in sequence along the arrangement direction, thereby improving the bandwidth of the antenna array structure. Both the antenna array unit 10 and the micro coaxial transmission line 20 are of micro coaxial structure, and the transmission size of the micro coaxial structure is small. After the sequential rotation feeding structure is formed by the plurality of antenna array units 10, the array structure can also be kept in a small volume, having the characteristics of low profile and compact structure, and realizing low transmission loss, thereby improving the antenna gain. The antenna array unit 10 includes a micro coaxial feeding structure 11, a metal support column 13, and a metal disk 12. The phase difference between the two feeding probes 14 in the micro coaxial feeding structure 11 is 90 degrees, realizing the circular polarization of the antenna array unit 10. By extending the two feeding probes 14 close to the metal support column 13 and located between the metal floor 30 and the metal disk 12, the transmission loss can be reduced and the antenna gain can be improved.

[0053] In order to verify the performance of the antenna array unit 10 in the present invention, Figure 2 and Figure 3 the antenna array unit 10 in is simulated. The key dimensions of the antenna array unit 10 are as follows: the length of the antenna array unit 10 is 4.59 mm, the width is 4.13 mm, the length of the feeding probe 14 is 1.05 mm, the radius of the metal support column 13 is 0.29 mm, the height is 0.24 mm, the radius of the metal disk 12 is 1.28 mm, the thickness is 0.24 mm, and the thickness of the metal floor 30 is 0.06 mm. The simulation results are as shown in Figure 5 and Figure 6 : Figure 5 is the simulation curve graph of the reflection coefficient and gain of the antenna array unit 10, Figure 6 is the simulation curve graph of the axial ratio of the antenna array unit 10. The impedance bandwidth of the antenna array unit 10 is 17.9%, |S11| ≤ -10 dB (54.9 - 65.7 GHz), the maximum gain is 9.4 dBic, the AR bandwidth of the antenna array unit 10 is 4.1% (59.5 - 62 GHz), and AR ≤ 3 dB.

[0054] In some embodiments of the present invention, please refer to Figure 1, the number of antenna array units 10 is four, and the phase difference between two adjacent antenna array units 10 is 90 degrees. For example, the phase of the first antenna array unit 10 is 0°, the phase of the second antenna array unit 10 is 90°, the phase of the third antenna array unit 10 is 180°, and the phase of the fourth antenna array unit 10 is 270°, thus forming sequential rotation feeding. In other embodiments, the number of antenna array units 10 can also be six, eight, etc., and the phase difference between two adjacent antenna array units 10 is 360° / N, where N is the number of antenna array units 10.

[0055] Figure 7 are the current simulation distribution diagrams of the antenna array unit 10 at 0°, 90°, 180°, and 270° phases at 60 GHz, as Figure 7 shown, the current direction rotates clockwise, thus forming left-handed circular polarization (LHCP) radiation.

[0056] To verify the performance of the circularly polarized patch antenna array structure in the present invention, the Figure 1 circularly polarized patch antenna array structure is simulated. The antenna array units 10 are arranged in a 2×2 sequential rotation feeding manner, and the phase difference between two adjacent antenna array units 10 is 90 degrees. The key dimensions of the circularly polarized patch antenna array structure are as follows: the distance between adjacent antenna array units 10 is 4 mm (0.8 λ , where λ is the free space wavelength at a frequency of 60 GHz). The total size of the circularly polarized patch antenna array structure is 11.5 mm×10 mm×0.36 mm. The key dimensions of the antenna array unit 10 are as follows: the length of the antenna array unit 10 is 4.59 mm, the width is 4.13 mm, the length of the feeding probe 14 is 1.05 mm, the radius of the metal support post 13 is 0.29 mm, the height is 0.24 mm, the radius of the metal disk 12 is 1.28 mm, the thickness is 0.24 mm, and the thickness of the metal floor 30 is 0.06 mm. The simulation results are as Figures 8 to 10 : Figure 8 is the simulation curve diagram of the reflection coefficient and gain of the circularly polarized patch antenna array structure, as Figure 8 shown, the impedance bandwidth of this antenna array structure is 18.1% (from 54.8 GHz to 65.7 GHz), and the peak gain within the impedance bandwidth is 14.62 dBic; Figure 9 is the simulation curve diagram of the axial ratio of the circularly polarized patch antenna array structure, as Figure 9 shown, the AR bandwidth of the antenna array structure is 15.8% (AR≤3 dB, from 55.7 GHz to 64.2 GHz); Figure 10 is the simulation curve diagram of the radiation efficiency of the circularly polarized patch antenna array structure, asFigure 10 As shown, within the impedance bandwidth, the simulated radiation efficiency is greater than 82%, and the peak radiation efficiency is 91%. In summary, compared with other millimeter-wave patch antenna arrays, the antenna array structure of the present invention adopts a micro-coaxial structure, which has good transmission characteristics and a compact structure, realizes low transmission loss, and thus improves the antenna gain. Secondly, by adopting the sequential rotation feeding method for the micro-coaxial antenna array unit 10, not only the problem that the sequential rotation feeding is likely to increase the antenna size is avoided, but also the circular polarization axial ratio bandwidth is expanded. Therefore, the antenna array structure provides a better choice for the 60 GHz communication system.

[0057] In some embodiments of the present invention, please refer to Figure 1 , the micro-coaxial transmission line 20 has a second feeding input end 24 and four second output ends. The transmission distance between the second feeding input end 24 and each second output end is the second transmission distance, and the difference between the second transmission distances of two adjacent second output ends is 1 / 4 wavelength corresponding to the operating frequency. The micro-coaxial transmission line 20 is fed at the second feeding input end 24, and the micro-coaxial transmission line 20 transmits the electromagnetic waves generated by the feeding to each second output end respectively, and then transmits them to each antenna array unit 10. The transmission distance between the second feeding input end 24 and each second output end can be understood as the length of the transmission line between the second feeding input end 24 and the second output end. Each second output end corresponds to a transmission distance. Since the second transmission distances are different, the phases of the electromagnetic waves when transmitted to each second output end are different. When the transmission distance between two second output ends is 1 / 4 wavelength, the phase difference of the electromagnetic waves at the two second output ends is 90 degrees. Among them, the operating frequency is the center frequency at resonance of the antenna array structure.

[0058] By adjusting the lengths of the second transmission distances, the phases of the second output ends can be adjusted, and thus the sequential rotation feeding of the antenna array structure can be realized.

[0059] In some embodiments of the present invention, please refer to Figure 1 , the transmission outer shell 21 is provided with a feeding hole 211 at the second feeding input end 24, and the transmission inner core 22 has a stepped structure 221 extending towards the feeding hole 211 at the second feeding input end 24. The stepped structure 221 includes a plurality of stepped units with gradually decreasing cross-sections. Among them, the stepped unit with the largest cross-section is connected to the transmission inner core 22, and the stepped unit with the smallest cross-section is close to the feeding hole 211. When feeding the micro-coaxial transmission line 20, the high-level end passes through the feeding hole 211 and is connected to the stepped structure 221 (the stepped unit with a smaller cross-section), and the low-level end is connected to the transmission outer shell 21 near the feeding hole 211.

[0060] By setting the stepped structure 221, the impedance of the transmission inner core 22 at the second feed input end 24 can be made more continuous, achieving better impedance matching.

[0061] In some embodiments of the present invention, the operating frequency of the circularly polarized patch antenna array structure is from 57 GHz to 66 GHz. For example, the operating frequencies are 60 GHz, 62 GHz, and so on. The unlicensed frequency band near 57 GHz - 66 GHz (60 GHz band) has the application prospect of providing high data rates for indoor short-range communication systems. Since the radio signal transmission loss in the 60 GHz band is very large, it is crucial to study high-efficiency high-gain antenna arrays for 60 GHz communication systems.

[0062] In some embodiments of the present invention, please refer to Figure 11 and Figure 12 , the micro coaxial feed structure 11 has a first feed input end 1101 and two first output ends 1102. The transmission distance between the first feed input end 1101 and each first output end 1102 is the first transmission distance, and the difference between the two first transmission distances is 1 / 4 wavelength corresponding to the operating frequency. The micro coaxial transmission line 20 feeds power to the first feed input end 1101. After passing through the micro coaxial feed structure 11, it feeds power to the two feed probes 14 via the two first output ends 1102 respectively. The transmission distance between the first feed input end 1101 and each first output end 1102 can be understood as the length of the transmission structure between the first feed input end 1101 and the first output end 1102. When the difference between the two first transmission distances is 1 / 4 wavelength corresponding to the operating frequency, the phase difference between the two feed probes 14 is 90 degrees.

[0063] The two feed probes 14 are arranged perpendicular to each other. By adjusting the difference between the two first transmission distances, the phase difference between the two feed probes 14 can be adjusted to make the phase difference between them 90 degrees, so as to achieve circular polarization of the antenna array unit 10.

[0064] In some embodiments of the present invention, please refer to Figure 11 and Figure 12, the micro coaxial feeding structure 11 includes a main feeding structure 113, a first feeding section 114, a second feeding section 115, and a third feeding section 116. The first feeding section 114, the second feeding section 115, and the third feeding section 116 are sequentially and perpendicularly connected. One end of the main feeding structure 113 is a first feeding input end 1101, and the other end is connected to the second feeding section 115. One end of the first feeding section 114 away from the second feeding section 115 and one end of the third feeding section 116 away from the second feeding section 115 are both first output ends 1102. A reference point 117 is set at the connection of the main feeding structure 113 and the second feeding section 115. The distance from the reference point 117 to one of the first output ends 1102 forms one branch feeding structure 118, and the distance from the reference point 117 to the other first output end 1102 forms the other branch feeding structure 118. The first feeding section 114 and the second feeding section 115 are perpendicular to each other, and the second feeding section 115 and the third feeding section 116 are perpendicularly arranged. When the lengths of the two branch feeding structures 118 are different, a phase difference will be formed at the two first output ends 1102.

[0065] By connecting the main feeding structure 113 to the second feeding section 115, two different branch feeding structures 118 are formed. By adjusting the position of the connection (reference point 117) between the main feeding structure 113 and the second feeding section 115, the lengths of the two branch feeding structures 118 can be adjusted, and thus the phase difference between the two feeding probes 14 can be adjusted.

[0066] In some embodiments, when the reference point 117 is located at a non - mid - point position of the second feeding section 115, the lengths of the two branch feeding structures 118 are different, so a phase difference will be formed at the two first output ends 1102.

[0067] In some embodiments, the reference point 117 is located at the mid - point position of the second feeding section 115, and the lengths of the first feeding section 114 and the second feeding section 115 are different, making the lengths of the two branch feeding structures 118 different, so a phase difference will be formed at the two first output ends 1102.

[0068] In some embodiments of the present invention, please refer to Figure 11 and Figure 12, the resistance of the inner feeding part 112 of the two branch feeding structures 118 is 50 Ω. The inner feeding part 112 of the main feeding structure 113 includes a first inner feeding section 1131 and a second inner feeding section 1132 which are connected to each other. One end of the second inner feeding section 1132 away from the first inner feeding section 1131 is located at the reference point 117. The cross-sectional area of the first inner feeding section 1131 is smaller than that of the second inner feeding section 1132. The resistance of the first inner feeding section 1131 is 50 Ω, and the resistance of the second inner feeding section 1132 is 35 Ω. Among them, both the branch feeding structure 118 and the main feeding structure 113 include an outer layer structure (part of the outer feeding part 111) and an inner layer structure (part of the inner feeding part 112), and the resistance of the inner feeding part 112 is related to its length. One end of the first inner feeding section 1131 is connected and conducted with the transmission inner core 22, and the other end of the first inner feeding section 1131 is connected and conducted with the second inner feeding section 1132. Due to their different cross-sections, a stepped structure is formed at the connection of the first inner feeding section 1131 and the second inner feeding section 1132.

[0069] The inner feeding parts 112 of the two branch feeding structures 118 can be understood as being connected in parallel, and their resistances are both 50 Ω. Therefore, the resistance at the reference point 117 is 25 Ω. In order to achieve better impedance matching, the inner feeding part 112 of the main feeding structure 113 is set as the first inner feeding section 1131 and the second inner feeding section 1132 with different cross-sections. The resistances of the first inner feeding section 1131 and the second inner feeding section 1132 are 50 Ω and 35 Ω respectively, so as to achieve better impedance matching and reduce signal reflection.

[0070] In order to verify that the micro coaxial feeding structure 11 provided by the present invention has good impedance matching and less signal reflection, Figure 11 and Figure 12 the provided micro coaxial feeding structure 11 is simulated. The key parameters are: the width of one end of the second inner feeding section 1132 close to the reference point 117 is 180 µm, the distance between the second inner feeding section 1132 and the inner feeding part 112 on the left is 1753 µm, and the distance between the second inner feeding section 1132 and the inner feeding part 112 on the right is 453 µm. The simulation results are as shown in Figure 13 and Figure 14 , Figure 13 is the simulation curve graph of the reflection coefficient of the micro coaxial feeding structure 11, Figure 14 is the phase difference curve graph of the two first output ends 1102 of the micro coaxial feeding structure 11. It can be seen from Figure 13 that the reflection coefficient of the first feeding input end 1101 is lower than -15 dB, and the energy to the two first output ends 1102 is almost equal, realizing good impedance matching and equal power output characteristics. Among them, S 11 is the input reflection coefficient, and S 12is the reverse transmission coefficient of one of the ports. S 13 is the reverse transmission coefficient of the other port. As can be seen from Figure 14 the phase difference between the two first output ends 1102 is 90° ± 10° in the frequency band of 53 - 65 GHz, which is the key reason for realizing the circular polarization characteristic.

[0071] In some embodiments of the present invention, please refer to Figure 15 and Figure 16 inside the transmission housing 21 there is a dielectric support structure 23, and the transmission inner core 22 is located on the dielectric support structure 23. The dielectric support structure 23 is made of an insulating material and is used to support the transmission inner core 22 to form an interval space between the transmission inner cores 22.

[0072] In some embodiments, the dielectric support structure 23 can be a strip structure, and its two ends are respectively lapped at both ends in the width direction of the transmission housing 21. The number of the dielectric support structures 23 is multiple, and they are arranged at intervals in the length direction of the transmission housing 21.

[0073] In some embodiments, the dielectric support structure 23 is an SU - 8 dielectric strip.

[0074] Optionally, the thickness of the dielectric support structure 23 can be 20 µm.

[0075] In some embodiments of the present invention, the micro - coaxial feeding structure 11 also includes the above - mentioned dielectric support structure 23, and the dielectric support structure 23 is arranged inside the outer feeding part 111 and is used to support the inner feeding part 112.

[0076] In some embodiments of the present invention, please refer to Figure 1 , Figure 11 and Figure 15 on both the transmission housing 21 and the outer feeding part 111 there are process holes 40, and the function of the process holes 40 is to facilitate cleaning the dielectric materials inside the transmission housing 21 and the outer feeding part 111. The number and distribution of the process holes 40 are not limited here and can be selected according to specific situations.

[0077] The present invention also provides a circularly polarized patch antenna array system, and the circularly polarized patch antenna array system includes a plurality of circularly polarized patch antenna array structures in any of the above - mentioned embodiments, and the plurality of circularly polarized patch antenna array structures can be connected through a feeding network.

[0078] The circularly polarized patch antenna array system provided by the present invention adopts the above-mentioned circularly polarized patch antenna array structure. The circularly polarized patch antenna array structure includes a plurality of antenna array units 10 and a micro coaxial transmission line 20 connecting each antenna array unit 10. The plurality of antenna array units 10 are sequentially rotated by a predetermined angle along the arrangement direction to achieve a sequential rotation feeding structure, thereby improving the bandwidth of the antenna array structure. Both the antenna array unit 10 and the micro coaxial transmission line 20 are of micro coaxial structure. The transmission size of the micro coaxial structure is small. After the sequential rotation feeding structure is formed by the plurality of antenna array units 10, the array structure can also be maintained in a small volume, having the characteristics of low profile and compact structure, and also achieving low transmission loss, thereby improving the antenna gain. The antenna array unit 10 includes a micro coaxial feeding structure 11, a metal support column 13, and a metal disk 12. The phase difference between the two feeding probes 14 in the micro coaxial feeding structure 11 is 90 degrees, realizing the circular polarization of the antenna array unit 10. By extending the two feeding probes 14 to be close to the metal support column 13 and located between the metal floor 30 and the metal disk 12, the transmission loss can be reduced and the antenna gain can be improved.

[0079] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A circularly polarized patch antenna array structure, characterized in that: The invention comprises a plurality of antenna array units evenly spaced in the circumferential direction, a micro-coaxial transmission line connecting each of the antenna array units, and a metal floor, wherein the antenna array units and the micro-coaxial transmission line are both arranged on the metal floor, and each of the antenna array units is arranged in sequence by rotating a predetermined angle along the arrangement direction, and the product of the predetermined angle and the number of the antenna array units is 360 degrees. The antenna array unit comprises a micro-coaxial feeding structure, a metal support column and a metal plate, one end of the metal support column is connected to the metal floor, and the other end of the metal support column is connected to the metal plate, the micro-coaxial feeding structure comprises an external feeding part and an internal feeding part arranged on the external feeding part, the internal feeding part has two feeding probes extending out of the external feeding part, the two feeding probes both extend between the metal plate and the metal floor and one end of the feeding probe is arranged close to the metal support column, the two feeding probes are arranged perpendicular to each other, and the phase difference between the outputs of the two feeding probes is 90 degrees; The micro-coaxial transmission line comprises a transmission shell and a transmission inner core arranged inside the transmission shell, the transmission shell is connected to the external power feeding part, and the transmission inner core is connected to the internal power feeding part; The micro-coaxial feeding structure has a first feeding input end and two first output ends, the transmission distance between the first feeding input end and each of the first output ends is a first transmission distance, and the difference between the two first transmission distances is 1 / 4 wavelength corresponding to the operating frequency; The micro-coaxial feeding structure includes a main feeding structure, a first feeding segment, a second feeding segment and a third feeding segment, wherein the first feeding segment, the second feeding segment and the third feeding segment are vertically connected in sequence, one end of the main feeding structure is the first feeding input end, and the other end is connected to the second feeding segment, and one end of the first feeding segment away from the second feeding segment and one end of the third feeding segment away from the second feeding segment are both the first output ends; the connection between the main feeding structure and the second feeding segment is set as a reference point, the reference point to one of the first output ends is one of the branch feeding structures, and the reference point to another of the first output ends is another branch feeding structure.

2. The circularly polarized patch antenna array structure according to claim 1, characterized in that: The resistance of the internal feeding parts of the two branch feeding structures is 50Ω, the internal feeding part of the main feeding structure includes a first internal feeding segment and a second internal feeding segment connected to each other, the second internal feeding segment is located at the reference point at one end away from the first internal feeding segment, the cross-sectional area of ​​the first internal feeding segment is smaller than the cross-sectional area of ​​the second internal feeding segment, the resistance of the first internal feeding segment is 50Ω, and the resistance of the second internal feeding segment is 35Ω.

3. The circularly polarized patch antenna array structure according to any one of claims 1 to 2, characterized in that: The transmission shell has a dielectric support structure inside, and the transmission core is located on the dielectric support structure.

4. The circularly polarized patch antenna array structure according to any one of claims 1 to 2, characterized in that: The number of the antenna array units is four, and the phase difference between two adjacent antenna array units is 90 degrees.

5. The circularly polarized patch antenna array structure according to claim 4, characterized in that: The micro-coaxial transmission line has a second feeding input end and four second output ends, the transmission distance between the second feeding input end and each of the second output ends is a second transmission distance, and the difference in the second transmission distance between two adjacent second output ends is 1 / 4 wavelength corresponding to the operating frequency.

6. The circularly polarized patch antenna array structure according to claim 5, characterized in that: The transmission shell is provided with a feeding hole at the second feeding input end, and the transmission inner core has a stepped structure extending toward the feeding hole at the second feeding input end.

7. The circularly polarized patch antenna array structure according to any one of claims 1 to 2, characterized in that: The operating frequency of the circularly polarized patch antenna array structure is 57 GHz to 66 GHz.

8. A circularly polarized patch antenna array system, characterized in that: The invention comprises a circularly polarized patch antenna array structure as described in any one of claims 1 to 7.

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