A circularly polarized PSOAM array antenna, control method, and wireless communication system

Abstract

The present invention belongs to the technical field of antennas, and discloses a circularly polarized PSOAM array antenna, a control method, and a wireless communication system. The circularly polarized PSOAM array antenna adopts an integrated antenna and feeder structure, and is composed of a dielectric substrate and a coaxial cable feeder; wherein, on the upper surface of the dielectric board, 8 array units are evenly distributed along a circle with a specific radius; on the lower surface of the dielectric board, a 9-port Wilkinson power divider feeding network is printed. Eight identical array units are distributed on the upper surface of the dielectric substrate. The array unit antenna includes four bent monopoles, four L-shaped microstrip lines, a cross-shaped microstrip line for feeding, and a circular metal sheet for impedance matching. The bent monopole replaces the monopole by bending a copper column by 90°. The present invention solves the problem of single polarization of the PSOAM antenna and realizes the miniaturization of the PSOAM array antenna.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly relates to a circularly polarized PSOAM array antenna, a control method, and a wireless communication system. Background Art

[0002] At present, while OAM provides unique degrees of freedom, it also has characteristics that restrict its practical application, including phase singularities and beam divergence angles. To solve the problems encountered by OAM beams during propagation, PSOAM antennas have emerged. However, the research on PSOAM antennas is still in the stage of method exploration. Most of the existing antennas have a relatively high profile, and the practicability and functionality of the polarization mode are not strong, which poses challenges to the compatibility of PSOAM antennas with wireless communication systems. Currently, all PSOAM antennas are linearly polarized, and the practicability of the polarization mode is weak. During the transmission and reception of antenna signals, it is necessary to comprehensively consider its polarization angle to place the antenna position to avoid polarization loss caused by polarization mismatch. The circular array is one of the common ways to implement PSOAM beams. Its principle is easy to understand and the structure is simple. The diversity and functionality of the array antenna depend on the type of unit antenna. Therefore, it is of great value to design a PSOAM array antenna with circular polarization characteristics.

[0003] The prior art is as follows:

[0004] The literature "Jin, Xiaofeng, Zhang, et al. Generation of plane spiral OAM waves using traveling-wave circular slot antenna [J]. IEEE Antennas and Wireless Propagation Letters, 2016, 16: 8 - 11." uses a traveling-wave metal resonator to generate OAM beams. Then, by opening a circular horn slot line around the metal resonator, the beam energy can be concentrated in the horizontal plane direction, and the PSOAM beam can be realized. The OAM mode purity of this antenna is high, but the size is large, which is not conducive to the superposition of multi-modalities. At the same time, the non-circularity of the omnidirectional end-fire radiation pattern of this antenna is relatively large, and it still needs to be optimized to meet the practical conditions.

[0005] The literature "Hua L, Zheng S, Yu X, et al. Transformation of OAM Waves to PlaneSpiral OAM Waves Based on Gradient-Index Meta-Surface[C] / / 2018Asia-PacificMicrowave Conference(APMC). IEEE, 2018:120-122." uses a dielectric resonator placed in the middle region of the metasurface to generate an OAM beam, and the metasurface loaded around the resonator enables the OAM beam to propagate along the plane where the metasurface is located through specific sub-wavelength structural units and arrangement methods. This antenna has the disadvantages of large size, narrow impedance bandwidth, small 3dB beam width, and complex metasurface design. At the same time, the antenna design has not been made into a physical object, making it difficult to verify the feasibility of the method.

[0006] The literature "Dong R, Chen Y, Zheng S, et al. Generation ofplane spiral orbitalangular momentum microwave with ring dielectric resonator antenna[C] / / 2017Sixth Asia-Pacific Conference on Antennas and Propagation(APCAP). IEEE, 2017:1-3." uses a dielectric resonator to generate an OAM beam and significantly reduces the antenna size by filling a dielectric with a high dielectric constant into the dielectric resonator. This antenna has achieved a good miniaturization level and has a relatively high modal purity, but its radiation efficiency and gain are severely limited due to its too small electrical size.

[0007] The literature "Ma Q, Zheng S, Zheng J, et al. Realization of Structured Electromagnetic Waves Based on Plane Spiral Orbital Angular Momentum Waves Using Circular Cylindrical Conformal Microstrip Antenna Array [C] / / 2018 Asia-Pacific Microwave Conference (APMC). IEEE, 2018: 91-93." generates OAM beams using a circular uniform annular array, and generates PSOAM beams by means of cylindrical conformal so that each array element radiates radially outward. However, the electrical size of the feeding network is much larger than the antenna itself, which greatly limits its integration with communication devices.

[0008] The structure of the literature "Chen Y, Zheng S, Wang X, et al. Dipole Antenna Array Fed by a SIW Based Circular Resonator for Generating Plane Spiral Orbital Angular Momentum Wave [C] / / 2019 Photonics & Electromagnetics Research Symposium-Fall (PIERS-Fall). IEEE, 2019: 1510-1514" consists of 30 dipole antennas with omnidirectional radiation characteristics and a HMSIW feeding network based on a circular resonator. Compared with the PSOAM array antenna, it does not require a complex feeding network and can generate vortex electromagnetic waves with high modal purity; compared with the resonant cavity PSOAM antenna, it has the ability to realize multi-mode PSOAM beams. However, the relatively high profile is still one of the disadvantages of this antenna, and its non-planar structure also makes it difficult to integrate into a communication system. At the same time, the omnidirectional non-circularity of this antenna is relatively large, and it cannot meet the requirement of 3dB non-circularity for omnidirectionality in practical applications.

[0009] It can be seen that while realizing the circularly polarized PSOAM beam, it is a challenging task to meet the requirements of miniaturization, easy integration, and good circularity. While OAM provides unique degrees of freedom, it also has characteristics that restrict its practical application, including phase singularities and beam divergence angles. To address the problems encountered by OAM beams during propagation, the PSOAM antenna came into being. However, the current research on PSOAM antennas is still in the stage of method exploration. Most of the existing antennas have a relatively high profile, and the practicality and functionality of the polarization method are not strong, which poses challenges to the compatibility between PSOAM antennas and wireless communication systems. The problems that need to be solved mainly include the following two aspects:

[0010] (1) The research on the structure of low-profile PSOAM antennas has not been carried out. The profile of the antenna is a key factor determining the ease of integration with communication equipment. Although the current research on PSOAM antennas is still in the stage of exploring generation methods and has not discussed the low-profile characteristics, the significance of low-profile characteristics for antenna integration cannot be ignored. At present, the PSOAM antennas based on UCA adopt two structures: cylindrical conformal and inserted. For the former, the Butler matrix is used in the feeding network and is not integrated with the antenna; the latter has a compact structure but also has the drawback of a relatively high profile. The PSOAM antennas based on the principle of circular traveling waves generally have the problems of large size and difficulty in integration. To sum up, there are few implementation methods for current PSOAM antennas, and their profiles are all relatively high, which is not conducive to integration.

[0011] (2) The implementation method of circularly polarized PSOAM antennas has not been explored. Due to the existence of phase singularities and beam divergence angles in OAM beams, it poses challenges to the reception and demultiplexing of OAM beams. The transverse propagation property of PSOAM beams overcomes the influence of these two problems on beam reception. However, current PSOAM antennas are all linearly polarized, and the practicality of the polarization method is weak. During the transmission and reception of antenna signals, it is necessary to comprehensively consider the polarization angle to place the antenna to avoid polarization loss caused by polarization mismatch. To sum up, the current polarization method of PSOAM antennas is relatively single, which poses great challenges to the transmission and reception of signals.

[0012] Through the above analysis, the problems and defects of the existing technology are as follows: In the existing technology, while realizing the PSOAM beam, it is impossible to meet the requirements of low profile and circular polarization of the antenna.

[0013] The difficulty in solving the above problems and defects is as follows: The difficulty in realizing a circularly polarized PSOAM beam lies in that the PSOAM antenna is an omnidirectional antenna with an omnidirectional radiation pattern. If planar structural elements are used to form an array, omnidirectional radiation can be achieved by evenly distributing the array elements along the radial direction. However, the circular polarization of the planar structural element antenna is basically realized through multiple layers, and the radiation direction is along the direction of the multiple layers. This results in that after forming them into a planar array, the radiation direction will not achieve uniform radiation along the horizontal plane. In this regard, choosing an end-fire antenna with a vertical structure is a feasible option. The horizontal plane radiation is covered by each unit radiating in a different angle, and then using a vertical structure will bring a relatively prominent problem, one is the simplification of the array design, and the other is the requirement for a low-profile antenna at the initial design stage. Therefore, in the design of a low-profile circularly polarized PSOAM antenna, there are urgent requirements for the profile of the unit antenna, the radiating antenna, and the design complexity.

[0014] The significance of solving the above problems and defects is as follows: The vortex electromagnetic wave radiated by this antenna can increase the communication capacity, expand the multiplexing dimension, miniaturization is beneficial to its integrated development, and circular polarization is beneficial to the accurate reception of electromagnetic waves as the transmitting and receiving end antennas. The combination of these three has great value. Summary of the Invention

[0015] In view of the problems existing in the prior art, the present invention provides a circularly polarized PSOAM array antenna, a control method, and a wireless communication system.

[0016] The present invention is implemented as follows. A control method for a circularly polarized PSOAM array antenna, the control method for the circularly polarized PSOAM array antenna includes: bending a monopole into an L-shaped monopole, and changing the horizontal and vertical components of the current of the array unit by adjusting the bending height of the L-shaped monopole to achieve the design of circular polarization.

[0017] Another object of the present invention is to provide a circularly polarized PSOAM array antenna, the circularly polarized PSOAM array antenna adopts an integrated antenna-feed structure and is composed of a dielectric substrate and a coaxial feeder cable;

[0018] Among them, on the upper surface of the dielectric board, 8 array units are evenly distributed along a circle with a specific radius; on the lower surface of the dielectric board, a 9-port Wilkinson power divider feeding network is printed.

[0019] Furthermore, eight identical array units are distributed on the upper surface of the dielectric substrate. The array unit antenna includes four bent monopoles, four L-shaped microstrip lines, a cross-shaped microstrip line for feeding, and a circular metal sheet for impedance matching.

[0020] Furthermore, the bent monopole is formed by bending a copper column by 90° to replace the monopole.

[0021] Furthermore, the circular metal sheet for impedance matching is located at the center of the array unit antenna and jointly forms the feeder part of the unit with the cross-shaped microstrip line.

[0022] Furthermore, the L-shaped microstrip line and the cross-shaped feeder on the dielectric substrate jointly form two horizontal circular currents with the horizontal section of the inverted L-shaped monopole, while the vertical section of the inverted L-shaped monopole forms four vertical linear currents.

[0023] Furthermore, the bent monopole is an L-shaped monopole. By adjusting the bending height of the L-shaped monopole, the horizontal and vertical components of the current of the array unit are changed to achieve the design of circular polarization and reduce the profile height of the array antenna.

[0024] Furthermore, the bent monopole is provided with eight excitation ports for the bent monopoles, which are represented by port 1 to port 8 respectively. The eight units are rotationally symmetrically distributed around the origin, and the rotation angle is 45°; the 8 units are respectively rotated clockwise by 15° around their respective geometric centers;

[0025] The output phases of the eight output ports are equivalent to 0°, 135°, 270°, 45°, 180°, 315°, 90° and 225°.

[0026] Furthermore, the top of the dielectric board is the radiation unit, and the bottom is the metal ground. The diameter of the bottom metal ground is slightly smaller than the diameter of the dielectric board.

[0027] Furthermore, the Wilkinson power dividing and feeding network is a topological structure of a parallel microstrip feeding network. It is composed of 7 three-port Wilkinson power dividers and 7 sections of microstrip lines for phase shift, and they form a 540° phase shift power divider, two 270° phase shift power dividers and four 135° phase shift power dividers.

[0028] Furthermore, the outer surface of the coaxial feeder cable is connected to the metal ground on the lower layer of the dielectric board, and the inner core is connected to the input port of the feeding network on the upper layer of the dielectric board through the through hole on the dielectric board.

[0029] Another object of the present invention is to provide a wireless communication system, and the wireless communication system is installed with the circularly polarized PSOAM array antenna.

[0030] Combining all the above technical solutions, the advantages and positive effects of the present invention are as follows: Since there are phase singularities and beam divergence angles in the OAM beam, this poses challenges to the reception and demultiplexing of the OAM beam. The property of the PSOAM beam propagating transversely enables it to overcome the influence of these two problems on beam reception. However, currently, all PSOAM antennas are linearly polarized, and the practicality of the polarization method is relatively weak. In the transmission and reception of antenna signals, it is necessary to comprehensively consider the polarization angle to place the antenna position to avoid polarization loss caused by polarization mismatch. To sum up, the current polarization method of PSOAM antennas is relatively single, posing great challenges to the transmission and reception of signals. Aiming at the problems of high profile, large non-circularity, and weak practicality of the polarization method of current PSOAM antennas, based on the principle of generating PSOAM by a circular array, a circularly polarized PSOAM array antenna with a low profile and good omnidirectional characteristics is designed by using a bent monopole circularly polarized unit antenna.

[0031] The present invention solves the problem of single polarization of PSOAM antennas and realizes the miniaturization of PSOAM array antennas. The bandwidth of the array antenna has a voltage standing wave ratio less than 2 within 2.05 - 2.96 GHz. The non-circularity of the antenna pattern in the xoy plane is less than 2.56 dB, meeting the requirements of omnidirectionality. There is approximately 20 dB of isolation between the cross-polarization (RHCP) and the co-polarization (LHCP) of the array. The beam energy of the array is mainly concentrated in the direction of θ = 90°, meaning the beam propagates transversely. The simulated peak gain of the antenna is 0.5 dB, and the measured peak gain is 0.46 dB. In the maximum radiation direction (θ = 90°), the measured axial ratio ranges from 0.3 dB to 2.3 dB in the entire angular plane. Moreover, it has a certain 3 dB axial ratio beam width, and the θ angle range with an axial ratio less than 3 dB is [67°, 107°] and [253°, 293°]. Three vortex arms representing the vortex mode can be clearly seen on the observation plane. The profile height of the array antenna is only 0.13λ0. The present invention realizes circular polarization. Brief Description of the Drawings

[0032] Figure 1 is a schematic structural diagram of the circularly polarized PSOAM array antenna provided by an embodiment of the present invention.

[0033] Figure 2 is a schematic diagram of the antenna in an oblique view provided by an embodiment of the present invention.

[0034] Figure 3 is a schematic diagram of the bottom of the antenna provided by an embodiment of the present invention.

[0035] Figure 4 is the S of the antenna provided by an embodiment of the present invention 11 curve graph.

[0036] Figure 5It is the axial ratio curve graph of the antenna provided by the embodiment of the present invention;

[0037] In the figure: Figure a is θ = 90°; Figure b is

[0038] Figure 6 It is the 3D radiation pattern of the antenna provided by the embodiment of the present invention.

[0039] Figure 7 It is the schematic diagram of the phase distribution of the antenna provided by the embodiment of the present invention on the observation surface.

[0040] Figure 8 It is the schematic diagram of the electric field superposition of the N - element antenna array provided by the embodiment of the present invention.

[0041] Figure 9 It is the schematic diagram of the far - field calculation model of the circular - array provided by the embodiment of the present invention; in the figure: (a) UCA model; (b) far - field calculation model.

[0042] Figure 10 It is the schematic diagram of the pattern multiplication theorem provided by the embodiment of the present invention; in the figure: (a) array factor; (b) element antenna; (c) array antenna.

[0043] Figure 11 It is the schematic diagram of the measured result of the far - field radiation characteristics of the antenna provided by the embodiment of the present invention; in the figure: (a) E - plane radiation pattern; (b) H - plane radiation pattern. Specific implementation manners

[0044] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further details the present invention in combination with 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.

[0045] Aiming at the problems existing in the prior art, the present invention provides a circularly polarized PSOAM array antenna, a control method, and a wireless communication system. The following describes the present invention in detail with reference to the accompanying drawings.

[0046] Ordinary technical personnel in the industry for the circularly polarized PSOAM array antenna provided by the present invention can also implement it using other steps. Figure 1 The circularly polarized PSOAM array antenna provided by the present invention is only a specific embodiment.

[0047] Such as Figures 1-3As shown in the figure, the circularly polarized PSOAM array antenna provided by the embodiments of the present invention adopts an integrated antenna and feeder design, and is composed of a dielectric substrate and a coaxial feeder cable. Among them, on the upper surface of the dielectric substrate, 8 array units 2 are evenly distributed along a circle with a specific radius; at the center position of the upper surface of the dielectric substrate, a 9-port Wilkinson power divider feeding network is printed; on the lower surface of the dielectric substrate, a metal ground 3 of the feeding network 1 is printed.

[0048] Eight identical array units are distributed on the upper surface of the dielectric substrate. The array unit antenna includes four bent monopoles, four L-shaped microstrip lines, a cross-shaped microstrip line for feeding, and a circular metal sheet for impedance matching. The bent monopole is formed by bending a copper column by 90° to replace the monopole. The circular metal sheet for impedance matching is located at the center position of the array unit antenna and jointly forms the feeding line part of the unit with the cross-shaped microstrip line. The L-shaped microstrip line and the cross-shaped feeder on the dielectric substrate and the horizontal section of the inverted L-shaped monopole jointly form two horizontal circular currents, while the vertical section of the inverted L-shaped monopole forms four vertical linear currents.

[0049] The bent monopole is an L-shaped monopole. By adjusting the bending height of the L-shaped monopole, the horizontal and vertical components of the current of the array unit are changed to achieve the design of circular polarization. At the same time, the profile height of the array antenna is reduced. The integrated antenna and feeder design is also a method to achieve a low profile.

[0050] The excitation ports of the eight bent monopoles are respectively represented by ports 1 to 8. The eight units are rotationally symmetrically distributed with the origin as the center, and the rotation angle is 45°. Due to considering the connection between the unit and the output port of the feeding network, the 8 units are respectively rotated clockwise by 15° around their respective geometric centers. The output phases of the eight output ports are equivalent to 0°, 135°, 270°, 45°, 180°, 315°, 90° and 225°.

[0051] The top of the dielectric substrate is the radiation unit, and the bottom is the metal ground. In order to improve the axial ratio, the diameter of the bottom metal ground is slightly smaller than the diameter of the dielectric substrate.

[0052] The Wilkinson power divider feeding network is a topological structure of a parallel microstrip feeding network. It is composed of 7 three-port Wilkinson power dividers and 7 sections of microstrip lines for phase shift, and they form a 540° phase shift power divider, two 270° phase shift power dividers and four 135° phase shift power dividers.

[0053] The outer skin of the coaxial feeder cable is connected to the metal ground on the lower layer of the dielectric substrate, and the inner core is connected to the input port of the feeding network on the upper layer of the dielectric substrate through a through hole on the dielectric substrate.

[0054] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0055] The present invention first elaborates on the basic theory of the pattern multiplication theorem

[90] to better explain the principle of generating OAM beams based on a circular array. To make the elaboration process concise and clear, it is assumed in the following theoretical analysis that the radiation characteristics of the array elements are the same and the mutual coupling effect between the elements is not taken into account. Therefore, as Figure 8 shown, the total field of the array antenna can be regarded as the superposition of the vector electric fields of the array elements.

[0056] Assume that the origin of the coordinate system is the phase reference center, and the array elements are distributed near the phase reference center. Denote the phase center of the nth element as c n (x n , y n , z n ), and the excitation current is I n . The radiation field generated by the nth element at the observation point is:

[0057]

[0058] In the formula, B is the proportionality coefficient of the array element, r n is the distance from the observation point to the nth array element, is the normalized direction function of the array element. Since each array element is similar, B and of each array element are the same. Assume the following approximate relationships in the far field:

[0059]

[0060] where,

[0061] r n ≈ r - e r ·c n (2-10)

[0062]

[0063] c n = x n e x + y n e y + z n e z (2-12)

[0064] Then,

[0065]

[0066] Substitute it into formula (2-10):

[0067]

[0068] Substituting Eqs. (2-9) and (2-14) into Eq. (2-8), the radiated electric field of the nth element can be expressed as:

[0069]

[0070] Since the polarization directions of all elements are the same, the array radiation field can be regarded as the scalar sum of the radiated fields of the elements. Therefore, the total field of the antenna array can be expressed as:

[0071]

[0072] The direction function of the array antenna is obtained as:

[0073]

[0074] where is the element factor of the element. Therefore, the array factor can be expressed as:

[0075]

[0076] Therefore, the relationship can be obtained as:

[0077]

[0078] Eq. (2-19) is the mathematical expression of the pattern multiplication theorem for a circular array antenna, and its physical meaning is that the pattern function of the circular array is the product of the array factor pattern function and the element pattern function. This indicates that the far-field radiation characteristics of the circular array antenna are jointly determined by the array configuration and the element characteristics.

[0079] As Figure 9 shown, the UCA for theoretical calculation consists of N similar elements arranged along a circle, a is the radius of the array, all elements are distributed in a plane, and the position of the element is represented by the azimuth angle . Among them, N is the number of elements, and n is the element ordinal number (n = 0, 1, 2,..., N - 1).

[0080] As Figure 9 shown, assuming that the center of the circular array is the phase reference center O, r represents the vector radius between the observation point in the far field and the phase reference center.

[0081] Let P n = [a cos(2πn / N), a sin(2πn / N), 0] represent the coordinates of the nth element, and use to represent the unit vector of the incident signal. At the same time, assuming that the incident signal first arrives at point O and then at the nth element, the time delay of the nth element relative to point O can be expressed as:

[0082]

[0083] The corresponding phase shift can be expressed as:

[0084]

[0085] Let the excitation source be I is the current amplitude, and β n is the phase of the nth excitation source. Similarly, the total vector sum of the electric field can be represented by a scalar sum, that is, it can be expressed as:

[0086]

[0087] Among them, the array factor is:

[0088]

[0089] To obtain the OAM electromagnetic wave of l mode, let From (2-23), we can get:

[0090]

[0091] When the number of array elements N is large enough, that is is small enough, the above formula can be integrated as:

[0092]

[0093] Among them, J l (2πa λ sinθ) is the lth order Bessel function of the first kind, and a λ is the electrical size length of the array radius, and k represents the wave number.

[0094] It can be seen from equation (2-25) that the array factor of the UCA contains the phase factor of OAM From this, it can be proved that under the excitation of equal amplitude and constant phase difference, the UCA has the ability to generate OAM beams. Among them, the constant phase difference is 2πl / N, that is, when the electromagnetic wave rotates one week forward along the propagation axis, its spatial phase will change by 2πl. Therefore, the radiated electric field will also have a phase difference of 2πl in the plane, and the vortex electromagnetic wave of l mode is its manifestation form. From this, it can be inferred that although the array elements in the above analysis are ideal isotropic elements, the uniform circular array can generate orbital angular momentum, which is also applicable to arrays using other unit antennas.

[0095] In addition, the number of array elements N of the UCA determines the maximum OAM mode number l that can be achieved using it. The relationship between the number of array elements and the generated mode number is predicted as: -N / 2 < l < N / 2. To sum up, when N = 8, the UCA can theoretically generate seven modes, i.e., l = 0, ±1, ±2, ±3, and the corresponding continuous phase differences between adjacent array elements are 0°, ±45°, ±90°, ±135° respectively.

[0096] It can be seen from this that for a circular array antenna, to convert an OAM beam into a PSOAM beam, it is necessary to reasonably design the arrangement and element structure of the array antenna. Therefore, the principle of generating PSOAM by a circular array antenna can be summarized as: on the basis of generating vortex electromagnetic waves based on a uniform circular array, the beam energy is concentrated in the plane through a special array arrangement. There are mainly two implementation forms: one is to use directional unit antennas to form an array to evenly cover the entire azimuth plane with energy; the other is to use omnidirectional unit antennas to form an array. From the above analysis of the pattern multiplication theorem, it can be known that the array pattern in this array formation method still maintains the omnidirectional radiation characteristic. In the present invention, based on the first implementation method, microstrip Yagi directional antennas are formed into a circular array as shown in Figure 10 (b), and the directivity of the unit antenna is used to make its beam radiate outward along the radius. After the array beams are superimposed, a PSOAM beam with omnidirectional and uniform radiation is formed. Based on the second implementation method, the unit selects a bent monopole omnidirectional antenna, and the broadside characteristic of the array factor pattern of the circular array is used, and the array composed of it can realize the PSOAM beam. The schematic diagram of the pattern multiplication theorem used above is shown in Figure 10 .

[0097] It should be noted that in order to obtain a better omnidirectional broadside pattern, the non-circularity in the plane must be less than 3 dB, which requires that the half-power beamwidth of the array elements in the xoy plane meets certain conditions, that is, HPBW xoy ≥45°. At the same time, the array radius is also a key factor affecting beam synthesis. In order to generate vortex electromagnetic waves while ensuring good omnidirectionality, it is necessary to reasonably select the array radius in the design.

[0098] The technical effects of the present invention will be further described below in combination with simulation experiments.

[0099] The present invention solves the problem of the single polarization of the PSOAM antenna and realizes the miniaturization of the PSOAM array antenna. The bandwidth of the array antenna has a voltage standing wave ratio of less than 2 within 2.05 - 2.96 GHz. The circularity of the antenna pattern in the xoy plane is less than 2.56 dB, meeting the requirement of omnidirectionality. There is approximately 20 dB of isolation between the cross polarization (RHCP) and the main polarization (LHCP) of the array. The beam energy of the array is mainly concentrated in the direction of θ = 90°, meaning the beam propagates transversely. The simulated peak gain of the antenna is 0.5 dB, and the measured peak gain is 0.46 dB. In the maximum radiation direction (θ = 90°), the measured axial ratio ranges from 0.3 dB to 2.3 dB across the entire angular plane. Moreover, it has a certain 3 dB axial ratio beam width, and the θ angle range with an axial ratio less than 3 dB is [67°, 107°] and [253°, 293°]. Three vortex arms representing the vortex mode can be clearly seen on the observation plane. The profile height of the array antenna is only 0.13λ0. The present invention realizes circular polarization. As Figure 11 shown, a schematic diagram of the measured results of the far - field radiation characteristics of the antenna; Figure 11 in which (a) is the E - plane radiation pattern; (b) is the H - plane radiation pattern.

[0100] In the description of the present invention, unless otherwise specified, "a plurality of" means two or more; the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientation or positional relationships shown in the drawings, and are 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 construed as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0101] The above - mentioned is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention shall be covered by the protection scope of the present invention.

Claims

1. A control method for a circularly polarized PSOAM array antenna, characterized in that, The control method of the circularly polarized PSOAM array antenna includes: bending the monopole into an L-shaped monopole, and changing the horizontal and vertical components of the current of the array element by adjusting the bending height of the L-shaped monopole to achieve the design of circular polarization; The circularly polarized PSOAM array antenna adopts an integrated antenna-feed structure and is composed of a dielectric substrate and a coaxial feeder cable; Among them, on the upper surface of the dielectric board, 8 array elements are evenly distributed along a circle with a specific radius; on the lower surface of the dielectric board, a 9-port Wilkinson power divider feeding network is printed; The bent monopole is formed by bending a copper column by 90° to replace the monopole; The circular metal sheet for impedance matching is located at the center of the array element antenna and jointly forms the feeder part of the element with the cross-shaped microstrip line; The bent monopole is provided with eight excitation ports of the bent monopole, which are respectively represented by port 1 to port 8. The eight units are rotationally symmetrically distributed around the origin, and the rotation angle is 45°; the 8 units are respectively rotated clockwise by 15° around their respective geometric centers; The output phases of the eight output ports are equivalent to 0°, 135°, 270°, 45°, 180°, 315°, 90° and 225°; The top of the dielectric board is the radiation element, and the bottom is the metal ground. The diameter of the bottom metal ground is slightly smaller than the diameter of the dielectric board; The Wilkinson power divider feeding network is a topological structure of a parallel microstrip feeding network. It is composed of 7 three-port Wilkinson power dividers and 7 sections of microstrip lines for phase shift. They form a 540° phase shift power divider, two 270° phase shift power dividers and four 135° phase shift power dividers; The outer surface of the coaxial feeder cable is connected to the metal ground on the lower layer of the dielectric board, and the inner core is connected to the input port of the feeding network on the upper layer of the dielectric board through the through hole on the dielectric board.

2. The control method of the circularly polarized PSOAM array antenna according to claim 1, wherein The L-shaped microstrip line and the cross-shaped feeder on the dielectric substrate and the horizontal section of the inverted L-shaped monopole jointly form two horizontal circular currents, and the vertical section of the inverted L-shaped monopole forms four vertical linear currents.

3. The control method of the circularly polarized PSOAM array antenna according to claim 1, characterized in that, The bent monopole is an L-shaped monopole. By adjusting the bending height of the L-shaped monopole, the horizontal and vertical components of the current of the array element are changed to achieve the design of circular polarization and reduce the profile height of the array antenna.

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