Circularly polarized patch antenna array structure and system

Abstract

The invention provides a circularly polarized patch antenna array structure and system.The circularly polarized patch antenna array structure comprises a plurality of antenna array units which are evenly distributed in the circumferential direction at intervals, a micro-coaxial transmission line and a metal floor, each antenna array unit comprises a micro-coaxial feed structure, a metal supporting column and a metal disc, one end of each metal supporting column is connected with the metal floor, and the other end of each metal supporting column is connected with the micro-coaxial transmission line; the other end of the metal supporting column is connected with the metal disc, the micro-coaxial feed structure comprises an outer feed part and an inner feed part arranged on the outer feed part, the inner feed part is provided with two feed probes extending out of the outer feed part, the two feed probes extend to the position between the metal disc and the metal floor, one end of each feed probe is arranged close to the metal column, and the other end of each feed probe is arranged close to the metal disc. The two feed probes are perpendicular to each other, and the phase difference output by the two feed probes is 90 degrees. The antenna array units and the micro-coaxial transmission lines are of micro-coaxial structures, are small in size, have the advantages of being low in profile and compact in structure, achieve low transmission loss and further improve antenna gain.

Description

Technical Field

[0001] The present invention belongs to the field of electromagnetic wave technology, and more specifically, relates to a circular polarization patch antenna array structure and system. Background Art

[0002] Antenna arrays usually contain a large number of radiating elements and require a low-loss feeding network. First, for the feeding element, the metal waveguide has low transmission loss and can achieve high gain characteristics of the antenna. However, it is bulky and not suitable for millimeter-wave planar circuit integration. Microstrip lines have the advantages of compact structure and simple integration, so they are widely used in antenna feeding networks. However, microstrip lines usually have high dielectric losses, especially when designing large arrays. As a planar waveguide transmission line, substrate integrated waveguide has been widely used in the design of millimeter-wave antenna arrays due to its low loss and high cost-effectiveness. The above antenna form has a high profile, which is not conducive to high integration. Secondly, for the feeding structure, the circularly polarized antenna array can be composed of an equiphase uniformly distributed feeding network and antenna elements. For an equiphase uniformly distributed feeding network, 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 object, the technical solution adopted by the present invention is: to provide a circularly polarized patch antenna array structure, comprising: 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 an 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.

[0005] 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.

[0006] Optionally, the micro-coaxial feeding structure includes a main feeding structure, a first feeding segment, a second feeding segment and a third feeding segment, 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, 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.

[0007] 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 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.

[0008] Optionally, the interior of the transmission shell has a medium support structure, and the transmission core is located on the medium support structure.

[0009] Optionally, the number of the antenna array units is four, and the phase difference between two adjacent antenna array units is 90 degrees.

[0010] 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 in the second transmission distance between two adjacent second output ends is 1 / 4 wavelength corresponding to the operating frequency.

[0011] Optionally, 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.

[0012] Optionally, the operating frequency of the circularly polarized patch antenna array structure is 57 GHz to 66 GHz.

[0013] 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.

[0014] The circularly polarized patch antenna array structure and system provided by the present invention have the following beneficial effects: compared with the prior art, the circularly polarized patch antenna array structure of the present invention includes a plurality of antenna array units and a micro-coaxial transmission line connecting each antenna array unit, the plurality of antenna array units are sequentially rotated by a predetermined angle along the arrangement direction to realize a sequentially rotating feeding structure, thereby improving the bandwidth of the antenna array structure, the antenna array unit and the micro-coaxial transmission line are both micro-coaxial structures, the transmission size of the micro-coaxial structure is small, after the plurality of antenna array units form a sequentially rotating feeding structure, the array structure can also be kept in a small volume, with the characteristics of low profile and compact structure, and also realizes 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 of the outputs of the two feeding probes in the micro-coaxial feeding structure is 90 degrees, realizing the circular polarization of the antenna array unit, and by extending the two feeding probes close to the metal support column and being located between the metal floor and the metal disk, the transmission loss can be reduced and the antenna gain can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 these drawings without paying creative work.

[0016] Figure 1 A front view of a circularly polarized patch antenna array structure provided by an embodiment of the present invention; Figure 2 A front view of an antenna array unit provided by an embodiment of the present invention; Figure 3 A side view of an antenna array unit provided by an embodiment of the present invention; Figure 4 A three-dimensional structural diagram of an antenna array unit provided in an embodiment of the present invention (the metal plate and the metal support column are not shown); Figure 5 for Figure 2 Simulation curve diagram of reflection coefficient and gain of antenna array unit; Figure 6 for Figure 2 A simulation curve diagram of the axial ratio of the antenna array unit; Figure 7 for Figure 2 Current simulation distribution diagram of the antenna array unit at 60GHz; Figure 8 for Figure 1 Simulation graph of reflection coefficient and gain of medium circular polarization patch antenna array structure; Fig. 9 for Figure 1 Simulation curve of the axial ratio of the medium circular polarization patch antenna array structure; Fig.10 for Figure 1 Simulation curve of radiation efficiency of medium circular polarization patch antenna array structure; Fig.11 A three-dimensional structural diagram of a micro-coaxial feeding structure provided in an embodiment of the present invention; Fig.12 A front view of an internal power feeder provided in an embodiment of the present invention; Fig.13 for Fig.11 Simulation curve diagram of reflection coefficient of micro-coaxial feeding structure in FIG. Fig.14 for Fig.11 A phase difference curve diagram of two first output ends of the micro-coaxial feeding structure; Fig.15 A partial three-dimensional structural diagram of a micro-coaxial transmission line provided by an embodiment of the present invention; Fig.16 A side view of a micro-coaxial transmission line provided by an embodiment of the present invention.

[0017] Among them, the reference numerals in the figure are: 10-antenna array unit; 11-micro coaxial feeding structure; 1101-first feeding input terminal; 1102-first output terminal; 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 plate; 13-metal supporting column; 14-feeding probe; 20-micro coaxial transmission line; 21-transmission housing; 211-feeding hole; 22-transmission inner core; 221-step structure; 23-medium support structure; 24-second feeding input terminal; 30-Metal floor; 40-Process hole. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 intended to limit the present invention.

[0019] 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.

[0020] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0022] Antenna arrays usually contain a large number of radiating elements and require a low-loss feeding network. First, for the feeding element, the metal waveguide has low transmission loss and can achieve high gain characteristics of the antenna. However, it is bulky and not suitable for millimeter-wave planar circuit integration. Microstrip lines have the advantages of compact structure and simple integration, so they are widely used in antenna feeding networks. However, microstrip lines usually have high dielectric losses, especially when designing large arrays. As a planar waveguide transmission line, substrate integrated waveguide has been widely used in the design of millimeter-wave antenna arrays due to its low loss and high cost-effectiveness. The above antenna form has a high profile, which is not conducive to high integration. Secondly, for the feeding structure, the circularly polarized antenna array can be composed of an equiphase uniformly distributed feeding network and antenna elements. For an equiphase uniformly distributed feeding network, the bandwidth of the antenna array is usually narrow.

[0023] In view of the above problems, the present application proposes a circularly polarized patch antenna array structure excited by a micro-coaxial transmission line 20, including a plurality of antenna array units 10, a micro-coaxial transmission line 20 and a metal floor 30. The plurality of antenna array units 10 are evenly spaced in the circumferential direction and rotated in sequence by a predetermined angle along the arrangement direction to realize sequential rotation feeding, thereby improving the bandwidth of the antenna array structure. By setting the feeding structure and the transmission line of the antenna array unit 10 as a micro-coaxial 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 feeding probes 14 of the micro-coaxial feeding structure 11 is 90 degrees, which realizes the circular polarization of the antenna array unit 10. The two feeding probes 14 extend close to the metal support column 13 and are located between the metal disk 12 and the metal floor 30, so that the gain of the antenna array unit 10 can be improved. The circularly polarized patch antenna array structure has broadband, high gain, high radiation efficiency and compact size, and can solve the technical problems of large transmission loss and narrow AR bandwidth in the related art.

[0024] The circularly polarized patch antenna array structure provided in an embodiment of the present invention is now described.

[0025] Please also read Figures 1 to 4 The circularly polarized patch antenna array structure includes a plurality of antenna array units 10 evenly spaced in the circumferential direction, a micro-coaxial transmission line 20 connecting each antenna array unit 10, and a metal floor 30. The antenna array units 10 and the micro-coaxial transmission line 20 are both arranged on the metal floor 30. Each antenna array unit 10 is rotated in sequence by a predetermined angle along the arrangement direction. The product of the predetermined angle and the number of antenna array units 10 is 360 degrees. The antenna array unit 10 includes a micro-coaxial feeding structure 11, a metal support column 13 and a metal plate 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 plate 12. The micro-coaxial feeding structure 11 includes an external feeding part 111 and an internal feeding part 112 arranged on the external feeding part 111. The internal feeding part 112 has two feeding probes 14 extending out of the external feeding part 111. The two feeding probes 14 both extend between the metal plate 12 and the metal floor 30, and one end of the feeding probe 14 is arranged close to the metal support column 13. The two feeding probes 14 are arranged perpendicular to each other, and the phase difference between the outputs of the two feeding probes 14 is 90 degrees. The micro-coaxial transmission line 20 includes a transmission shell 21 and a transmission core 22 disposed inside the transmission shell 21 . The transmission shell 21 is connected to the external power feeding portion 111 , and the transmission core 22 is connected to the internal power feeding portion 112 .

[0026] 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 evenly spaced circumferentially, which can be understood as the plurality of antenna array units 10 are distributed around a center point, and the corresponding center angles between any two adjacent antenna array units 10 are the same. For example, the number of antenna array units 10 is four, and the corresponding center angles between any two adjacent antenna array units 10 are 90 degrees; the number of antenna array units 10 is six, and the corresponding center angles between any two adjacent antenna array units 10 are 60 degrees. Each antenna array unit 10 is rotated in sequence along the arrangement direction at a predetermined angle. It can be understood that the "arrangement direction" is a circumferential direction, which can be a clockwise direction or a counterclockwise direction. For example, in the clockwise direction, the positions of the antenna array units 10 are the first position, the second position, ... the Nth position, respectively. 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, the antenna array units 10 can be arranged to form a sequential rotating feeding structure, which can not only improve the bandwidth of the antenna array structure, but also realize circular polarization.

[0027] The antenna array unit 10 includes a micro-coaxial feeding structure 11, a metal support column 13 and a metal plate 12. When the metal support column 13 and the metal plate 12 are projected onto the metal floor 30, the metal support column 13 is located in the projection area of ​​the metal plate 12, and the cross section of the metal support column 13 is smaller than the area of ​​the metal plate 12. The combination of the metal support column 13 and the metal plate 12 is similar to an "umbrella-shaped" or "mushroom-shaped" structure. The micro-coaxial feeding structure 11 includes an external feeding part 111 and an internal feeding part 112. The internal feeding part 112 is equivalent to being suspended in the external feeding part 111, and there is no other metal structure between the two. The internal feeding part 112 has two feeding probes 14 arranged perpendicular to each other. The feeding probes 14 are exposed to the external 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 plate 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.

[0028] 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 shell 21 and a transmission core 22. The transmission shell 21 and the transmission core 22 are both metal structures. The transmission shell 21 is connected and conducted with the external feeding part 111, and the transmission core 22 is connected and conducted with the internal feeding part 112. When the micro-coaxial transmission line 20 is fed, 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.

[0029] The circularly polarized patch antenna array structure in the above embodiment 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 realize a sequentially rotating feeding structure, thereby improving the bandwidth of the antenna array structure. The antenna array unit 10 and the micro-coaxial transmission line 20 are both micro-coaxial structures, and the transmission size of the micro-coaxial structure is small. After the plurality of antenna array units 10 form a sequentially rotating feeding structure, the array structure can also be kept in a small volume, with the characteristics of low profile and compact structure, and also realizes 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 output by 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 being located between the metal floor 30 and the metal disk 12, the transmission loss can be reduced and the antenna gain can be improved.

[0030] 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 the simulation is simulated, and 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 feed 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 plate 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 shown in FIG. Figure 5 and Figure 6 : Figure 5 is a simulation curve diagram of the reflection coefficient and gain of the antenna array unit 10, Figure 6is a simulation curve diagram 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, and the AR bandwidth of the antenna array unit 10 is 4.1% (59.5-62 GHz), AR≤3 dB.

[0031] In some embodiments of the present invention, see 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 a sequential rotation feeding. In other embodiments, the number of antenna array units 10 may 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.

[0032] Figure 7 : is a current simulation distribution diagram of the antenna array unit 10 at phases of 0°, 90°, 180° and 270° at 60 GHz, as shown in FIG. Figure 7 As shown, the current direction rotates clockwise, resulting in left-hand circularly polarized (LHCP) radiation.

[0033] In order to verify the performance of the circularly polarized patch antenna array structure in the present invention, Figure 1 The circularly polarized patch antenna array structure in the simulation is simulated. The antenna array units 10 are arranged in a 2×2 rotation feeding manner. 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 ,in 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 feed 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 plate 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 shown in Figure 2. Figures 8 to 10 : Figure 8 It is a simulation curve diagram of the reflection coefficient and gain of the circularly polarized patch antenna array structure, such as Figure 8As shown, the impedance bandwidth of the 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; Fig. 9 It is a simulation curve diagram of the axial ratio of the circularly polarized patch antenna array structure, such as Fig. 9 As shown, the AR bandwidth of the antenna array structure is 15.8% (AR≤3 dB, from 55.7 GHz to 64.2 GHz); Fig.10 It is a simulation curve diagram of the radiation efficiency of the circularly polarized patch antenna array structure, such as Fig.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 with good transmission characteristics and a compact structure, achieving lower transmission losses, thereby improving antenna gain. Secondly, by adopting sequential rotation feeding for the micro-coaxial antenna array unit 10, not only the problem of sequential rotation feeding easily increasing the antenna size is avoided, but also the circular polarization axis ratio bandwidth is expanded. Therefore, the antenna array structure provides a better choice for 60 GHz communication systems.

[0034] In some embodiments of the present invention, see Figure 1 , the micro-coaxial transmission line 20 has a second feeding input terminal 24 and four second output terminals. The transmission distance between the second feeding input terminal 24 and each second output terminal is the second transmission distance, and the difference in the second transmission distance between two adjacent second output terminals is 1 / 4 wavelength corresponding to the operating frequency. The micro-coaxial transmission line 20 is fed at the second feeding input terminal 24, and the micro-coaxial transmission line 20 transmits the electromagnetic waves generated by the feeding to each second output terminal respectively, and then transmits them to each antenna array unit 10. The transmission distance between the second feeding input terminal 24 and each second output terminal can be understood as the length of the transmission line between the second feeding input terminal 24 and the second output terminal. Each second output terminal corresponds to a transmission distance. Since each second transmission distance is different, the phase of the electromagnetic wave when it is transmitted to each second output terminal is different. When the transmission distance between the two second output terminals is 1 / 4 wavelength, the phase difference of the electromagnetic waves between the two second output terminals is 90 degrees. Among them, the operating frequency is the center frequency of the resonance of the antenna array structure.

[0035] By adjusting the length of each second transmission distance, the phase of each second output end can be adjusted, thereby realizing sequential rotation feeding of the antenna array structure.

[0036] In some embodiments of the present invention, see Figure 1The transmission shell 21 is provided with a feeding hole 211 at the second feeding input end 24, and the transmission core 22 has a step structure 221 extending toward the feeding hole 211 at the second feeding input end 24. The step structure 221 includes a plurality of step units with successively decreasing cross sections, wherein the step unit with the largest cross section is connected to the transmission core 22, and the step 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 step structure 221 (the step unit with a smaller cross section), and the low-level end is connected to the transmission shell 21 near the feeding hole 211.

[0037] By setting the step structure 221 , the impedance of the transmission core 22 at the second feeding input end 24 can be made more continuous, thereby achieving better impedance matching.

[0038] In some embodiments of the present invention, the operating frequency of the circularly polarized patch antenna array structure is 57 GHz to 66 GHz, for example, the operating frequency is 60 GHz, 62 GHz, etc. The unlicensed frequency band near 57 GHz-66 GHz (60 GHz band) has the application prospect of providing high data rate for indoor short-range communication systems. Since the radio signal transmission loss in the 60 GHz band is large, it is crucial to study high-efficiency high-gain antenna arrays for 60 GHz communication systems.

[0039] In some embodiments of the present invention, see Fig.11 and Fig.12 The micro-coaxial feeding structure 11 has a first feeding input terminal 1101 and two first output terminals 1102. The transmission distance between the first feeding input terminal 1101 and each first output terminal 1102 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 transmission line 20 feeds the first feeding input terminal 1101, and after passing through the micro-coaxial feeding structure 11, it feeds the two feeding probes 14 respectively through the two first output terminals 1102. The transmission distance between the first feeding input terminal 1101 and each first output terminal 1102 can be understood as the length of the transmission structure between the first feeding input terminal 1101 and the first output terminal 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 feeding probes 14 is 90 degrees.

[0040] The two feeding probes 14 are arranged perpendicular to each other. By adjusting the difference between the two first transmission distances, the phase difference between the two feeding probes 14 can be adjusted to make the phase difference therebetween 90 degrees, so as to realize circular polarization of the antenna array unit 10.

[0041] In some embodiments of the present invention, see Fig.11 and Fig.12The 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 vertically connected in sequence. One end of the main feeding structure 113 is a first feeding input terminal 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 terminals 1102. The connection between the main feeding structure 113 and the second feeding section 115 is set as a reference point 117. The reference point 117 to one of the first output terminals 1102 is one of the branch feeding structures 118, and the reference point 117 to another first output terminal 1102 is another 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 perpendicular to each other. 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 .

[0042] 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 point (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, thereby adjusting the phase difference between the two feeding probes 14.

[0043] In some embodiments, when the reference point 117 is located at a non-midpoint position of the second feeding segment 115 , the lengths of the two branch feeding structures 118 are different, and thus a phase difference is formed at the two first output ends 1102 .

[0044] In some embodiments, the reference point 117 is located at the midpoint of the second feeding segment 115 . The first feeding segment 114 and the second feeding segment 115 have different lengths, so that the lengths of the two branch feeding structures 118 are different, thereby forming a phase difference at the two first output ends 1102 .

[0045] In some embodiments of the present invention, see Fig.11 and Fig.12, the resistance of the inner feed section 112 of the two branch feed structures 118 is 50Ω, the inner feed section 112 of the main feed structure 113 includes a first inner feed section 1131 and a second inner feed section 1132 connected to each other, the second inner feed section 1132 is located at a reference point 117 away from one end of the first inner feed section 1131, the cross-sectional area of ​​the first inner feed section 1131 is smaller than the cross-sectional area of ​​the second inner feed section 1132, the resistance of the first inner feed section 1131 is 50Ω, and the resistance of the second inner feed section 1132 is 35Ω. Among them, the branch feed structure 118 and the main feed structure 113 both include an outer layer structure (part of the outer feed section 111) and an inner layer structure (part of the inner feed section 112), and the resistance of the inner feed section 112 is related to its length. One end of the first inner feed segment 1131 is connected to the transmission inner core 22, and the other end of the first inner feed segment 1131 is connected to the second inner feed segment 1132. Since the first inner feed segment 1131 and the second inner feed segment 1132 have different cross sections, a step structure is formed at the connection between the two.

[0046] The inner feeding parts 112 of the two branch feeding structures 118 can be understood as being arranged in parallel, and the resistance of each is 50Ω. Therefore, the resistance at the reference point 117 is 25Ω. In order to achieve better impedance matching, the inner feeding part 112 of the main feeding structure 113 is set to a first inner feeding segment 1131 and a second inner feeding segment 1132 with different cross-sections. The resistances of the first inner feeding segment 1131 and the second inner feeding segment 1132 are 50Ω and 35Ω, respectively, to achieve better impedance matching and reduce signal reflections.

[0047] In order to verify that the micro-coaxial feeding structure 11 provided by the present invention has good impedance matching and less signal reflection, Fig.11 and Fig.12 The provided micro-coaxial feeding structure 11 is simulated, and the key parameters are: the width of the second inner feeding section 1132 near the reference point 117 is 180µm, the distance between the second inner feeding section 1132 and the inner feeding portion 112 on the left is 1753µm, and the distance between the second inner feeding section 1132 and the inner feeding portion 112 on the right is 453µm. The simulation results are shown in FIG. Fig.13 and Fig.14 , Fig.13 is a simulation curve diagram of the reflection coefficient of the micro coaxial feeding structure 11, Fig.14 is a phase difference curve diagram of the two first output ends 1102 of the micro coaxial feeding structure 11, from Fig.13 It can be seen from the figure that the reflection coefficient of the first feeding input terminal 1101 is lower than -15 dB, and the energy to the two first output terminals 1102 is almost equal, achieving good impedance matching and equal power output characteristics. 11 is the input reflection coefficient, S 12is the reverse transmission coefficient of one of the ports. 13 is the reverse transmission coefficient of the other port. Fig.14 It can be seen that in the 53-65 GHz frequency band, the phase difference between the two first output ends 1102 is 90°±10°, which is the key reason for achieving circular polarization characteristics.

[0048] In some embodiments of the present invention, see Fig.15 and Fig.16 The transmission housing 21 has a dielectric support structure 23 inside, and the transmission core 22 is located on the dielectric support structure 23. The dielectric support structure 23 is made of insulating material and is used to support the transmission core 22 so that a spacing space is formed between the transmission cores 22.

[0049] In some embodiments, the medium support structure 23 may be a strip structure, with two ends thereof respectively overlapped at two ends in the width direction of the transmission housing 21. There are multiple medium support structures 23, which are sequentially arranged at intervals along the length direction of the transmission housing 21.

[0050] In some embodiments, dielectric support structure 23 is a SU-8 dielectric strip.

[0051] Optionally, the thickness of the dielectric support structure 23 may be 20 μm.

[0052] In some embodiments of the present invention, the micro-coaxial feeding structure 11 also includes the above-mentioned dielectric support structure 23 . The dielectric support structure 23 is disposed inside the external feeding portion 111 and is used to support the internal feeding portion 112 .

[0053] In some embodiments of the present invention, see Figure 1 , Fig.11 and Fig.15 The transmission housing 21 and the external power feeding unit 111 are both provided with process holes 40, which are used to facilitate cleaning of the dielectric material inside the transmission housing 21 and the external power feeding unit 111. The number and distribution of the process holes 40 are not limited here and can be selected according to specific circumstances.

[0054] The present invention also provides a circularly polarized patch antenna array system, which includes a plurality of circularly polarized patch antenna array structures in any of the above embodiments, and the plurality of circularly polarized patch antenna array structures can be connected via a feeding network.

[0055] 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 multiple antenna array units 10 and micro-coaxial transmission lines 20 connecting each antenna array unit 10. The multiple antenna array units 10 are rotated in sequence by a predetermined angle along the arrangement direction to realize a sequential rotation feeding structure, thereby improving the bandwidth of the antenna array structure. The antenna array unit 10 and the micro-coaxial transmission line 20 are both micro-coaxial structures. The transmission size of the micro-coaxial structure is small. After the multiple antenna array units 10 form a sequential rotation feeding structure, the array structure can also be kept in a small volume, with the characteristics of low profile and compact structure, and also achieves lower 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 plate 12. The phase difference output by the two feeding probes 14 in the micro-coaxial feeding structure 11 is 90 degrees, thereby realizing circular polarization of the antenna array unit 10. By extending the two feeding probes 14 close to the metal support column 13 and locating them between the metal floor 30 and the metal plate 12, the transmission loss can be reduced and the antenna gain can be improved.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should 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.

2. The circularly polarized patch antenna array structure according to claim 1, characterized in that: 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.

3. The circularly polarized patch antenna array structure as claimed in claim 2, characterized in that: 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.

4. The circularly polarized patch antenna array structure according to claim 3, 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.

5. The circularly polarized patch antenna array structure according to any one of claims 1 to 4, characterized in that: The transmission shell has a dielectric support structure inside, and the transmission core is located on the dielectric support structure.

6. The circularly polarized patch antenna array structure according to any one of claims 1 to 4, 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.

7. The circularly polarized patch antenna array structure according to claim 6, 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.

8. The circularly polarized patch antenna array structure according to claim 7, 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.

9. The circularly polarized patch antenna array structure according to any one of claims 1 to 4, characterized in that: The operating frequency of the circularly polarized patch antenna array structure is 57 GHz to 66 GHz.

10. 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 9.

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