Electrically Tunable Circularly Polarized Composite Multimodal Reconfigurable Orbital Angular Momentum Antenna

Abstract

The disclosed electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna of the present invention comprises a first dielectric substrate and a second dielectric substrate sequentially arranged from bottom to top. A third dielectric substrate is disposed above the second dielectric substrate, and an air layer is spaced between the third dielectric substrate and the second dielectric substrate. A metal feeding network is printed on the lower surface of the first dielectric substrate, and a metal ground plane having the same shape and size as that of the first dielectric substrate is printed on the upper surface of the first dielectric substrate. Four metal radiation patches are printed on the upper surface of the second dielectric substrate. The third dielectric substrate comprises four circular third dielectric substrate units of the same shape and size arranged on the same plane. A circular metal coupling patch of the same radius is printed on the lower surface of each third dielectric substrate unit. It further comprises four feeding probe units. This antenna can further overcome the problems of single performance during reconfiguration and complex array feeding network structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communication, and particularly relates to an electrically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna. Background Art

[0002] Against the backdrop of the booming development of artificial intelligence and its emergence as a global focus, big data, the Internet of Things, and intelligent technologies are constantly integrating and advancing. All these technologies require high-capacity, integrated, highly adaptable, and intelligent communication devices as strong support. However, currently, the spectrum resources are facing an extremely tense situation, and it is very necessary to alleviate the contradiction between new services and high capacity. To address the above problems, the commonly adopted solutions are technologies such as frequency division multiplexing, time division multiplexing, code division multiplexing, and space division multiplexing, which respectively correspond to widely recognized dimensional components such as frequency, time, code pattern, and space. Although these technologies have been relatively fully developed and utilized, they are still restricted by spectrum resources and traditional modulation technologies, and it is difficult to meet the requirements of the future ultra-high-speed development of wireless communication. The orbital angular momentum technology extends the multiplexing technology dimension to a new physical parameter, namely the mode. Since the mode order of the OAM beam can theoretically be any value, and the OAM beams with different mode orders are orthogonal to each other, by virtue of this inherent advantage, multiple co-frequency signals can be modulated onto the OAM beam to achieve multiplexed transmission of multiple channels of information on the same carrier frequency, realizing green, high-speed, and secure transmission.

[0003] In existing research, vortex beams can be excited by optical methods such as spiral phase plates or gratings, or by electromagnetic methods using array antennas or metamaterials. At the same time, the intelligent realization of multi-modal reconfigurable technology can expand the application fields of orbital angular momentum antennas and improve the communication rate, environmental adaptability, and anti-interference ability of antennas. Some scholars have conducted relevant research in this field. For example, in 2017, Q. Liu et al. loaded adjustable PIN diodes into a traditional microstrip feeding network, and used the on / off state of the PIN diodes to form different feeding structures, thereby generating two different configurations of array element excitation phases. Based on this principle, a dipole circular array with +1 and -1 two reconfiguration modes was designed. In 2018, Y. Y. Wang et al. used a circular patch antenna fed by a coupled probe as the basic model, and through the reasonable layout design of the broadband feeding network of the antenna and the coding of the PIN diodes therein, realized the electrically tunable reconfiguration function of 5 OAM beams. In 2018, L. Li et al. selected a planar spiral antenna as the array element to establish an 8-element broadband circularly polarized UCA. By mechanically rotating the array elements to form 7 phase differences with a step of -135° to 135°, 6 modes of vortex electromagnetic waves were generated while maintaining the equal-amplitude and in-phase excitation of the feeding network. The above latest research results have all achieved good reconfiguration functions of orbital angular momentum antennas, but there are also some limitations, such as single reconfigurable parameters, low accuracy and slow switching speed in the mechanical regulation method; the structure of the phase-shifting feeding network is relatively complex and requires a large number of regulating elements.

[0004] In addition, circularly polarized antennas have the functions of resisting multipath reflection interference and eliminating the "Faraday rotation" effect, so they have always been a research hotspot in the antenna field. Summary of the Invention

[0005] The purpose of the present invention is to provide an electrically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna, which uses circular polarization technology to enhance the anti-interference ability of the antenna, and at the same time combines the antenna polarization mode and the orbital angular momentum electromagnetic wave mode for composite reconfiguration, overcomes the problems of single performance and complex array feeding network structure during reconfiguration, and uses an electrically tunable method to improve the accuracy and speed during reconfiguration.

[0006] The technical solution adopted by the present invention is an electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna, which includes a first dielectric substrate and a second dielectric substrate arranged in sequence from bottom to top. A third dielectric substrate is arranged above the second dielectric substrate, and an air layer is spaced between the third dielectric substrate and the second dielectric substrate; the shapes of the first dielectric substrate and the second dielectric substrate are both squares of the same size; a metal feeding network is printed on the lower surface of the first dielectric substrate, and a metal ground plane in the shape of a square with the same shape and size as it is printed on the upper surface of the first dielectric substrate. Four metal radiation patches in the shape of rings with the same shape and size are printed on the upper surface of the second dielectric substrate, and the four metal radiation patches are evenly distributed on the same circumference; the third dielectric substrate includes four circular third dielectric substrate units arranged on the same plane, and the four third dielectric substrate units are respectively located directly above the four metal radiation patches, and the four third dielectric substrate units are arranged in one-to-one correspondence with the four metal radiation patches; a circular metal coupling patch with the same radius is printed on the lower surface of each third dielectric substrate unit;

[0007] It also includes four feeding probe units. Each unit includes four evenly distributed feeding probes. Each feeding probe unit respectively passes through the first dielectric substrate, the metal ground plane, and the second dielectric substrate from bottom to top to connect the metal radiation patch with the metal feeding network. The four feeding probe units are arranged in one-to-one correspondence with the four metal radiation patches.

[0008] The features of the present invention also lie in that

[0009] The metal feeding network includes four unit antenna feeding networks and an array system feeding network, and the four unit antenna feeding networks are all connected to the array system feeding network; the four unit antenna feeding networks are arranged in one-to-one correspondence with the four metal radiation patches, the four unit antenna feeding networks are respectively located directly below the four metal radiation patches, and every two adjacent unit antenna feeding networks are mirror-symmetrical. A unit antenna feeding network is connected to a metal radiation patch through a feeding probe unit.

[0010] The unit antenna feeding network includes a first power divider with a 1-to-2 equal-amplitude and in-phase output. An isolation resistor is welded between the two output ends of the first power divider. The two output ends of the first power divider are respectively connected to a first T-shaped single-pole double-throw switch and a second T-shaped single-pole double-throw switch with different excitation phases; each feeding probe unit includes four feeding probes. The first T-shaped single-pole double-throw switch is connected to the metal radiation patch through two feeding probes, and the second T-shaped single-pole double-throw switch is connected to the metal radiation patch through two feeding probes.

[0011] The feeding network of the array system includes a second power divider. Two output terminals of the second power divider are respectively connected with a third power divider. Two output terminals of each third power divider are respectively connected with the first power dividers of two unit antenna feeding networks. Isolation resistors are welded at two output terminals of the second power divider and two output terminals of the third power divider; the input terminal on the second power divider is the total feeding port.

[0012] The first T-shaped single-pole double-throw switch includes four PIN RF switches, a first main transmission line, and two first branch transmission lines arranged on the left and right sides at one end of the first main transmission line. The other end of the first main transmission line is connected with one of the output terminals of the first power divider. There are gaps between the two first branch transmission lines and the end of the first main transmission line. One PIN RF switch is arranged in one gap; a feeding probe is respectively arranged at a certain gap from the ends of the two first branch transmission lines away from the first main transmission line, and one PIN RF switch is arranged in one gap;

[0013] The second T-shaped single-pole double-throw switch includes four PIN RF switches, a second main transmission line, and two second branch transmission lines arranged on the left and right sides at one end of the second main transmission line. The other end of the second main transmission line is connected with one of the output terminals of the first power divider. There are gaps between the two second branch transmission lines and the end of the second main transmission line. One PIN RF switch is arranged in one gap; a feeding probe is respectively arranged at a certain gap from the ends of the two second branch transmission lines away from the second main transmission line, and one PIN RF switch is arranged in one gap;

[0014] The phases excited by the two feeding probes connected to the first branch transmission line are the same, and the phases excited by the two feeding probes connected to the second branch transmission line are the same; the phases excited by the two feeding probes connected to the first branch transmission line lag behind the phases excited by the two feeding probes connected to the second branch transmission line by 90 degrees.

[0015] The resistance value of the isolation resistor is 100 ohms.

[0016] The first dielectric substrate uses a square F4B dielectric material with a relative dielectric constant of 3.5 and a thickness of 0.5 mm, and the side length is 185 mm; the second dielectric substrate uses a square F4B dielectric material with a relative dielectric constant of 3.5 and a thickness of 0.5 mm, and the side length is 185 mm; the radius of the third dielectric substrate unit is 29 mm, and it is a FR4 substrate with a thickness of 1 mm.

[0017] The metal radiation patch is a circular ring-shaped metal radiation patch with an outer diameter of 14.5 mm and an inner diameter of 7.4 mm.

[0018] The position of each feeding probe is 11 mm away from the center of the circle of the metal radiation patch.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) The antenna of the present invention is based on a uniform circular array. Under the same antenna aperture, four kinds of vortex electromagnetic waves with a modal value of +1 and left- and right-handed circular polarization, and a modal value of -1 and left- and right-handed circular polarization can be generated respectively, thus realizing the characteristics of circular polarization and modal composite reconfigurability.

[0021] (2) In the antenna of the present invention, the phase difference of the array elements forming the multi-modal orbital angular momentum is only generated by the excitation phase difference of the unit antennas. Therefore, no external phase shifter is required in the system. When generating different states of vortex electromagnetic waves, only the switch state in the unit antenna needs to be changed. The switching speed is fast, the adjustment accuracy is high, the complex structural design during phase shift regulation is avoided, no auxiliary mechanical device is required, and the unit antenna forms are unified, the structure is simple, and it is easy to adjust.

[0022] (3) The antenna array and the feeding network of the present invention adopt printed circuit board technology, which is easy to process and manufacture. The unit antennas in the array adopt the form of coupled feeding. Compared with the OAM patch antenna directly fed by traditional microstrip lines, the working frequency band is relatively wide. Description of the Drawings

[0023] Figure 1 is a schematic diagram of the overall structure of the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna of the present invention;

[0024] Figure 2 is a schematic diagram of the structure of the feeding network of the first unit antenna of the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna of the present invention;

[0025] Figure 3 is a schematic diagram of the structure of the feeding network of the second unit antenna of the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna of the present invention;

[0026] Figure 4 is a schematic diagram of the structure of the feeding network of the third unit antenna of the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna of the present invention;

[0027] Figure 5 is a schematic diagram of the structure of the feeding network of the fourth unit antenna of the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna of the present invention;

[0028] Figure 6 is a schematic diagram of the structure of the system feeding network of the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna of the present invention;

[0029] Figure 7 is a schematic diagram of the echo loss characteristics of the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna provided by the embodiment of the present invention in different states;

[0030] Figure 8 It is a schematic diagram of the axial ratio characteristics of the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna provided by the embodiments of the present invention in different states;

[0031] Figure 9 It is a distribution diagram of the electric field phase when the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna provided by the embodiments of the present invention is left-hand circularly polarized and the OAM mode number is +1;

[0032] Figure 10 It is a distribution diagram of the electric field phase when the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna provided by the embodiments of the present invention is left-hand circularly polarized and the OAM mode number is -1;

[0033] Figure 11 It is a distribution diagram of the electric field phase when the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna provided by the embodiments of the present invention is right-hand circularly polarized and the OAM mode number is +1.

[0034] Figure 12 It is a distribution diagram of the electric field phase when the electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna provided by the embodiments of the present invention is right-hand circularly polarized and the OAM mode number is -1;

[0035] Figure 13 It is the normalized radiation pattern at the center frequency of 2.5 GHz when the antenna of the embodiments of the present invention operates in State 1.

[0036] Figure 14 It is the normalized radiation pattern at the center frequency of 2.5 GHz when the antenna of the embodiments of the present invention operates in State 2.

[0037] Figure 15 It is the normalized radiation pattern at the center frequency of 2.5 GHz when the antenna of the embodiments of the present invention operates in State 3.

[0038] Figure 16 It is the normalized radiation pattern at the center frequency of 2.5 GHz when the antenna of the embodiments of the present invention operates in State 4.

[0039] In the figure, 1. First dielectric substrate, 2. Second dielectric substrate, 3. Third dielectric substrate unit, 4. Metal radiation sheet, 5. Metal coupling patch, 6. Metal ground plane, 7. Feeding probe, 8. Metal feeding network, 9. Isolation resistor, 10. Total feeding port, 11. Feeding network of the first unit antenna, 12. Feeding network of the second unit antenna, 13. Feeding network of the third unit antenna, 14. Feeding network of the fourth unit antenna, 15. First power divider, 16. Second power divider, 17. Third power divider;

[0040] 8-1. Feeding network of the array system;

[0041] 11-1. First PIN RF switch a, 11-2. Second PIN RF switch a, 11-3. Third PIN RF switch a, 11-4. Fourth PIN RF switch a, 11-5. Fifth PIN RF switch a, 11-6. Sixth PIN RF switch a, 11-7. Seventh PIN RF switch a, 11-8. Eighth PIN RF switch a, 11-9. First main transmission line a, 11-10. First branch transmission line a, 11-11. Second main transmission line a, 11-12. Second branch transmission line a;

[0042] 12-1. First PIN RF switch b, 12-2. Second PIN RF switch b, 12-3. Third PIN RF switch b, 12-4. Fourth PIN RF switch b, 12-5. Fifth PIN RF switch b, 12-6. Sixth PIN RF switch b, 12-7. Seventh PIN RF switch b, 12-8. Eighth PIN RF switch b, 12-9. First main transmission line b, 12-10. First branch transmission line b, 12-11. Second main transmission line b, 12-12. Second branch transmission line b;

[0043] 13-1. First PIN RF switch c, 13-2. Second PIN RF switch c, 13-3. Third PIN RF switch c, 13-4. Fourth PIN RF switch c, 13-5. Fifth PIN RF switch c, 13-6. Sixth PIN RF switch c, 13-7. Seventh PIN RF switch c, 13-8. Eighth PIN RF switch c, 13-9. First main transmission line c, 13-10. First branch transmission line c, 13-11. Second main transmission line c, 13-12. Second branch transmission line c;

[0044] 14-1. First PIN RF switch d, 14-2. Second PIN RF switch d, 14-3. Third PIN RF switch d, 14-4. Fourth PIN RF switch d, 14-5. Fifth PIN RF switch d, 14-6. Sixth PIN RF switch d, 14-7. Seventh PIN RF switch d, 14-8. Eighth PIN RF switch d, 14-9. First main transmission line d, 14-10. First branch transmission line d, 14-11. Second main transmission line d, 14-12. Second branch transmission line d. Detailed implementation mode

[0045] The present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation modes.

[0046] The electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna of the present invention, such as Figure 1-6As shown in the figure, it includes a first dielectric substrate 1 and a second dielectric substrate 2 arranged in sequence from bottom to top. A third dielectric substrate is provided above the second dielectric substrate 2, and an air layer is spaced between the third dielectric substrate and the second dielectric substrate 2. The shapes of the first dielectric substrate 1 and the second dielectric substrate 2 are both squares of the same size. A metal feeding network 8 is printed on the lower surface of the first dielectric substrate 1, and a metal ground plane 6 in the shape of a square with the same shape and size as it is printed on the upper surface of the first dielectric substrate 1. Four metal radiation patches 4 in the shape of circles with the same shape and size are printed on the upper surface of the second dielectric substrate 2, and the four metal radiation patches 4 are evenly distributed on the same circumference. The third dielectric substrate includes four circular third dielectric substrate units 3 arranged on the same plane. The four third dielectric substrate units 3 are respectively located directly above the four metal radiation patches 4, and the four third dielectric substrate units 3 are arranged in one-to-one correspondence with the four metal radiation patches 4. A circular metal coupling patch 5 with the same radius is printed on the lower surface of each third dielectric substrate unit 3.

[0047] It also includes four feeding probe units. Each unit includes four evenly distributed feeding probes. Each feeding probe unit sequentially penetrates the first dielectric substrate 1, the metal ground plane 6, and the second dielectric substrate 2 from bottom to top to connect the metal radiation patch 4 with the metal feeding network 8. The four feeding probe units are arranged in one-to-one correspondence with the four metal radiation patches 4.

[0048] The metal feeding network 8 includes four unit antenna feeding networks and an array system feeding network 8-1. The four unit antenna feeding networks are all connected to the array system feeding network 8-1. The four unit antenna feeding networks are arranged in one-to-one correspondence with the four metal radiation patches 4. The four unit antenna feeding networks are respectively located directly below the four metal radiation patches 4. Each two adjacent unit antenna feeding networks are mirror symmetric. A unit antenna feeding network is connected to a metal radiation patch 4 through a feeding probe unit.

[0049] The unit antenna feeding network includes a first power divider 15 with a one-to-two equal-amplitude and in-phase output. An isolation resistor 9 is welded between the two output ends of the first power divider 15. The two output ends of the first power divider 15 are respectively connected to a first T-shaped single-pole double-throw switch and a second T-shaped single-pole double-throw switch with different excitation phases. Each feeding probe unit includes four evenly circularly distributed feeding probes 7. The first T-shaped single-pole double-throw switch is connected to the metal radiation patch 4 through two feeding probes 7, and the second T-shaped single-pole double-throw switch is connected to the metal radiation patch 4 through two feeding probes 7.

[0050] The feeding network 8-1 of the array system includes a second power divider 16. Two output terminals of the second power divider 16 are respectively connected with a third power divider 17. Two output terminals of each third power divider 17 are respectively connected with the first power divider 15 of two unit antenna feeding networks. Isolation resistors 9 are welded at two output terminals of the second power divider 16 and two output terminals of the third power divider 17. The input terminal on the second power divider 16 is the total feeding port 10.

[0051] The first T-shaped single-pole double-throw switch includes four PIN RF switches, a first main transmission line, and two first branch transmission lines arranged on the left and right sides of one end of the first main transmission line. One end of the first main transmission line is connected with one output terminal of the first power divider 15. There is a gap between the two first branch transmission lines and the end of the first main transmission line. One PIN RF switch is arranged in one gap. One feeding probe 7 is respectively arranged at a certain gap from the ends of the two first branch transmission lines away from the first main transmission line. One PIN RF switch is arranged in one gap.

[0052] The second T-shaped single-pole double-throw switch includes four PIN RF switches, a second main transmission line, and two second branch transmission lines arranged on the left and right sides of one end of the second main transmission line. The other end of the second main transmission line is connected with one output terminal of the first power divider 15. There is a gap between the two second branch transmission lines and the end of the second main transmission line. One PIN RF switch is arranged in one gap. One feeding probe 7 is respectively arranged at a certain gap from the ends of the two second branch transmission lines away from the second main transmission line. One PIN RF switch is arranged in one gap.

[0053] The phases excited by the two feeding probes 7 connected to the first branch transmission line are the same, and the phases excited by the two feeding probes 7 connected to the second branch transmission line are the same. The phases excited by the two feeding probes 7 connected to the first branch transmission line lag behind the phases excited by the two feeding probes 7 connected to the second branch transmission line by 90 degrees.

[0054] The first dielectric substrate 1 uses a square F4B dielectric material with a relative dielectric constant of 3.5 and a thickness of 0.5 mm, and the side length is 185 mm. The second dielectric substrate 2 uses a square F4B dielectric material with a relative dielectric constant of 3.5 and a thickness of 0.5 mm, and the side length is 185 mm. The third dielectric substrate unit 3 is an FR4 substrate with a radius of 29 mm and a thickness of 1 mm.

[0055] The metal radiation sheet 4 is a circular metal radiation sheet with an outer diameter of 14.5 mm and an inner diameter of 7.4 mm.

[0056] The position of each feeding probe 7 is 11 mm away from the center of the circle of the metal radiation sheet 4.

[0057] Embodiment

[0058] In the electronically tunable circularly polarized multi-modal reconfigurable orbital angular momentum antenna with the above structure, the first dielectric substrate 1 is made of a square F4B dielectric material with a relative dielectric constant of 3.5 and a thickness of 0.5 mm, and the side length is 185 mm. The second dielectric substrate 2 overlapped above the first dielectric substrate 1 is also made of a square F4B dielectric material with a relative dielectric constant of 3.5 and a thickness of 0.5 mm, and the side length is 185 mm. The metal radiation patch 4 is a circular ring-shaped metal radiation patch with an outer diameter of 14.5 mm and an inner diameter of 7.4 mm.

[0059] The third dielectric substrate 3 is a circular dielectric substrate with a thickness of 1 mm and a radius of 29 mm, and the material used is FR4 with a dielectric constant of 4.4. The air layer thickness between the third dielectric substrate unit and the second dielectric substrate 2 is 5 mm. The resistance value of the isolation resistor 9 is 100 ohms.

[0060] The first power divider 15, the second power divider 16 and the third power divider 17 are all Wilkinson power dividers with a 1-way to 2-way equal amplitude and in-phase.

[0061] The electronically tunable circularly polarized multi-modal reconfigurable orbital angular momentum antenna of the present invention includes four unit antenna feeding networks, which are respectively named the first unit antenna feeding network, the second unit antenna feeding network, the third unit antenna feeding network and the fourth unit antenna feeding network, and are numbered specifically as: the first unit antenna feeding network 11, the second unit antenna feeding network 12, the third unit antenna feeding network 13 and the fourth unit antenna feeding network 14.

[0062] As Figure 1 shown, the first unit antenna feeding network 11, the second unit antenna feeding network 12, the third unit antenna feeding network 13 and the fourth unit antenna feeding network 14 are arranged directly below the metal radiation patch 4, wherein the center point of the end of the second main transmission line coincides with the center of the metal radiation patch 4, and every two adjacent unit antenna feeding networks are mirror symmetric.

[0063] The arrangement of the feeding probes in the embodiment is as follows:

[0064] A feeding probe unit includes four feeding probes 7 evenly distributed on the circumference, the center of which coincides with the center of the metal radiation patch 4, and the radius is 11 mm.

[0065] As Figures 2-5As shown, the first T-type single-pole double-throw switches and the second T-type single-pole double-throw switches in the first unit antenna feed network 11, the second unit antenna feed network 12, the third unit antenna feed network 13, and the fourth unit antenna feed network 14 are distinguished as follows: The first T-type single-pole double-throw switch and the second T-type single-pole double-throw switch in the first unit antenna feed network 11 are represented by the first T-type single-pole double-throw switch a and the second T-type single-pole double-throw switch a, respectively; The first T-type single-pole double-throw switch and the second T-type single-pole double-throw switch in the second unit antenna feed network 12 are represented by the first T-type single-pole double-throw switch b and the second T-type single-pole double-throw switch b, respectively; The first T-type single-pole double-throw switch and the second T-type single-pole double-throw switch in the third unit antenna feed network 13 are represented by the first T-type single-pole double-throw switch c and the second T-type single-pole double-throw switch c, respectively; The first T-type single-pole double-throw switch and the second T-type single-pole double-throw switch in the fourth unit antenna feed network 14 are represented by the first T-type single-pole double-throw switch d and the second T-type single-pole double-throw switch d, respectively.

[0066] The first main transmission lines and the first branch transmission lines in the first T-type single-pole double-throw switch a, the first T-type single-pole double-throw switch b, the first T-type single-pole double-throw switch c, and the first T-type single-pole double-throw switch d are distinguished and numbered as follows: The first main transmission line and the first branch transmission line in the first T-type single-pole double-throw switch a are represented by the first main transmission line a11-9 and the first branch transmission line a11-10, respectively; The first main transmission line and the first branch transmission line in the first T-type single-pole double-throw switch b are represented by the first main transmission line b12-9 and the first branch transmission line b12-10, respectively; The first main transmission line and the first branch transmission line in the first T-type single-pole double-throw switch c are represented by the first main transmission line c13-9 and the first branch transmission line c13-10, respectively; The first main transmission line and the first branch transmission line in the first T-type single-pole double-throw switch d are represented by the first main transmission line d14-9 and the first branch transmission line d14-10, respectively.

[0067] Distinguish and assign numbers to the second main transmission lines and second branch transmission lines in the second T-type single-pole double-throw switches a, b, c, and d. Specifically: the second main transmission line and the second branch transmission line in the second T-type single-pole double-throw switch a are represented by the second main transmission line a11-11 and the second branch transmission line a11-12 respectively; the second main transmission line and the second branch transmission line in the second T-type single-pole double-throw switch b are represented by the second main transmission line b12-11 and the second branch transmission line b12-12 respectively; the second main transmission line and the second branch transmission line in the second T-type single-pole double-throw switch c are represented by the second main transmission line c13-11 and the second branch transmission line c13-12 respectively; the second main transmission line and the second branch transmission line in the second T-type single-pole double-throw switch d are represented by the second main transmission line d14-11 and the second branch transmission line d14-12 respectively.

[0068] Assign numbers to distinguish the 8 PIN RF switches on the first T-type single-pole double-throw switch a and the second T-type single-pole double-throw switch a. Specifically: the two PIN RF switches set on the two gaps between the two first branch transmission lines a11-10 and the end of the first main transmission line a11-09 are represented by the first PIN RF switch a11-1 and the second PIN RF switch a11-2; the two PIN RF switches located at the end gaps of the two first branch transmission lines a11-10 far from the first main transmission line a11-09 are represented by the third PIN RF switch a11-3 and the fourth PIN RF switch a11-4; the two PIN RF switches set on the two gaps between the two second branch transmission lines a11-12 and the end of the second main transmission line a11-11 are represented by the fifth PIN RF switch a11-5 and the sixth PIN RF switch a11-6; the two PIN RF switches located at the end gaps of the two second branch transmission lines a11-12 far from the second main transmission line a11-11 are represented by the seventh PIN RF switch a11-7 and the eighth PIN RF switch a11-8;

[0069] The eight PIN RF switches on the first T-type single-pole double-throw switch b and the second T-type single-pole double-throw switch b are respectively assigned numbers for distinction, specifically: the two PIN RF switches arranged on the two gaps between the two first branch transmission lines b12-10 and the end of the first main transmission line b12-09 are represented by the first PIN RF switch b12-1 and the second PIN RF switch b12-2; the two PIN RF switches located at the end gaps of the two first branch transmission lines b12-10 far from the first main transmission line b12-09 are represented by the third PIN RF switch b12-3 and the fourth PIN RF switch b12-4; the two PIN RF switches arranged on the two gaps between the two second branch transmission lines b12-12 and the end of the second main transmission line b12-11 are represented by the fifth PIN RF switch b12-5 and the sixth PIN RF switch b12-6; the two PIN RF switches located at the end gaps of the two second branch transmission lines b12-12 far from the second main transmission line b12-11 are represented by the seventh PIN RF switch b12-7 and the eighth PIN RF switch b12-8;

[0070] The eight PIN RF switches on the first T-type single-pole double-throw switch c and the second T-type single-pole double-throw switch c are respectively assigned numbers for distinction, specifically: the two PIN RF switches arranged on the two gaps between the two first branch transmission lines c13-10 and the end of the first main transmission line c13-09 are represented by the first PIN RF switch c13-1 and the second PIN RF switch c13-2; the two PIN RF switches located at the end gaps of the two first branch transmission lines c13-10 far from the first main transmission line c13-09 are represented by the third PIN RF switch c13-3 and the fourth PIN RF switch c13-4; the two PIN RF switches arranged on the two gaps between the two second branch transmission lines c13-12 and the end of the second main transmission line c13-11 are represented by the fifth PIN RF switch c13-5 and the sixth PIN RF switch c13-6; the two PIN RF switches located at the end gaps of the two second branch transmission lines c13-12 far from the second main transmission line c13-11 are represented by the seventh PIN RF switch c13-7 and the eighth PIN RF switch c13-8;

[0071] The 8 PIN RF switches on the first T-type single-pole double-throw switch d and the second T-type single-pole double-throw switch d are numbered for distinction. Specifically: the two PIN RF switches set on the two gaps between the two first branch transmission lines d14-10 and the end of the first main transmission line d14-09 are represented by the first PIN RF switch d14-1 and the second PIN RF switch d14-2; the two PIN RF switches located at the end gaps of the two first branch transmission lines d14-10 away from the first main transmission line d14-09 are represented by the third PIN RF switch d14-3 and the fourth PIN RF switch d14-4; the two PIN RF switches set on the two gaps between the two second branch transmission lines d14-12 and the end of the second main transmission line d14-11 are represented by the fifth PIN RF switch d14-5 and the sixth PIN RF switch d14-6; the two PIN RF switches located at the end gaps of the two second branch transmission lines d14-12 away from the second main transmission line d14-11 are represented by the seventh PIN RF switch d14-7 and the eighth PIN RF switch d14-8.

[0072] By controlling the on / off of the PIN RF switches in the antenna feed network of the control unit, the current path of the microstrip circuit is changed, and different modes and polarization methods are obtained. In this design, the antenna can achieve the following four states.

[0073] State 1: The first PIN RF switch a11-1, the third PIN RF switch a11-3, the sixth PIN RF switch a11-6, the eighth PIN RF switch a11-8, the first PIN RF switch b12-1, the third PIN RF switch b12-3, the fifth PIN RF switch b12-5, the seventh PIN RF switch b12-7, the first PIN RF switch c13-1, the third PIN RF switch c13-3, the sixth PIN RF switch c13-6, the eighth PIN RF switch c13-8, the first PIN RF switch d14-1, the third PIN RF switch d14-3, the fifth PIN RF switch d14-5, the seventh PIN RF switch d14-7 are turned on, and the second PIN RF switch a11-2, the fourth PIN RF switch a11-4, the fifth PIN RF switch a11-5, the seventh PIN RF switch a11-7, the second PIN RF switch b12-2, the fourth PIN RF switch b12-4, the sixth PIN RF switch b12-6, the eighth PIN RF switch b12-8, the second PIN RF switch c13-2, the fourth PIN RF switch c13-4, the fifth PIN RF switch c13-5, the seventh PIN RF switch c13-7, the second PIN RF switch d14-2, the fourth PIN RF switch d14-4, the sixth PIN RF switch d14-6, the eighth PIN RF switch d14-8 are turned off. The antenna of the present invention generates a left-handed circularly polarized OAM electromagnetic vortex beam with a mode number l = +1.

[0074] State 2: The first PIN RF switch a11-1, the third PIN RF switch a11-3, the sixth PIN RF switch a11-6, the eighth PIN RF switch a11-8, the second PIN RF switch b12-2, the fourth PIN RF switch b12-4, the sixth PIN RF switch b12-6, the eighth PIN RF switch b12-8, the first PIN RF switch c13-1, the third PIN RF switch c13-3, the sixth PIN RF switch c13-6, the eighth PIN RF switch c13-8, the second PIN RF switch d14-2, the fourth PIN RF switch d14-4, the sixth PIN RF switch d14-6, the eighth PIN RF switch d14-8 are turned on, and the second PIN RF switch a11-2, the fourth PIN RF switch a11-4, the fifth PIN RF switch a11-5, the seventh PIN RF switch a11-7, the first PIN RF switch b12-1, the third PIN RF switch b12-3, the fifth PIN RF switch b12-5, the seventh PIN RF switch b12-7, the second PIN RF switch c13-2, the fourth PIN RF switch c13-4, the fifth PIN RF switch c13-5, the seventh PIN RF switch c13-7, the first PIN RF switch d14-1, the third PIN RF switch d14-3, the fifth PIN RF switch d14-5, the seventh PIN RF switch d14-7 are turned off. The antenna of the present invention generates a left-handed circularly polarized OAM electromagnetic vortex beam with a mode number l=-1.

[0075] State three: The second PIN RF switch a11-2, the fourth PIN RF switch a11-4, the sixth PIN RF switch a11-6, the eighth PIN RF switch a11-8, the first PIN RF switch b12-1, the third PIN RF switch b12-3, the sixth PIN RF switch b12-6, the eighth PIN RF switch b12-8, the second PIN RF switch c13-2, the fourth PIN RF switch c13-4, the sixth PIN RF switch c13-6, the eighth PIN RF switch c13-8, the first PIN RF switch d14-1, the third PIN RF switch d14-3, the sixth PIN RF switch d14-6, the eighth PIN RF switch d14-8 are turned on, and the first PIN RF switch a11-1, the third PIN RF switch a11-3, the fifth PIN RF switch a11-5, the seventh PIN RF switch a11-7, the second PIN RF switch b12-2, the fourth PIN RF switch b12-4, the fifth PIN RF switch b12-5, the seventh PIN RF switch b12-7, the first PIN RF switch c13-1, the third PIN RF switch c13-3, the fifth PIN RF switch c13-5, the seventh PIN RF switch c13-7, the second PIN RF switch d14-2, the fourth PIN RF switch d14-4, the fifth PIN RF switch d14-5, the seventh PIN RF switch d14-7 are turned off. The antenna of the present invention generates a right-handed circularly polarized OAM electromagnetic vortex beam with a mode number l = +1.

[0076] State Four: The second PIN RF switch a11-2, the fourth PIN RF switch a11-4, the sixth PIN RF switch a11-6, the eighth PIN RF switch a11-8, the second PIN RF switch b12-2, the fourth PIN RF switch b12-4, the fifth PIN RF switch b12-5, the seventh PIN RF switch b12-7, the second PIN RF switch c13-2, the fourth PIN RF switch c13-4, the sixth PIN RF switch c13-6, the eighth PIN RF switch c13-8, the second PIN RF switch d14-2, the fourth PIN RF switch d14-4, the fifth PIN RF switch d14-5, the seventh PIN RF switch d14-7 are turned on, and the first PIN RF switch a11-1, the third PIN RF switch a11-3, the fifth PIN RF switch a11-5, the seventh PIN RF switch a11-7, the first PIN RF switch b12-1, the third PIN RF switch b12-3, the sixth PIN RF switch b12-6, the eighth PIN RF switch b12-8, the first PIN RF switch c13-1, the third PIN RF switch c13-3, the fifth PIN RF switch c13-5, the seventh PIN RF switch c13-7, the first PIN RF switch d14-1, the third PIN RF switch d14-3, the sixth PIN RF switch d14-6, the eighth PIN RF switch d14-8 are turned off. The antenna of the present invention generates a left-handed circularly polarized OAM electromagnetic vortex beam with a mode number l=-1.

[0077] The technical effects of the present invention are further described below in combination with simulation experiments:

[0078] As Figure 7 shown, when the left-handed circularly polarized OAM beam is excited with a mode value of +1 (State One), the frequency band range with return loss less than -15 dB is 2.40 - 2.67 GHz, and the relative bandwidth is 10.7%; when the left-handed circularly polarized OAM beam is excited with a mode value of -1 (State Two), the frequency band range with return loss less than -15 dB is 2.38 - 2.69 GHz, and the relative bandwidth is 12.2%; when the right-handed circularly polarized OAM beam is excited with a mode value of +1 (State Three), the frequency band range with return loss less than -15 dB is 2.38 - 2.68 GHz, and the relative bandwidth is 11.9%; when the right-handed circularly polarized OAM beam is excited with a mode value of -1 (State Four), the frequency band range with return loss less than -15 dB is 2.36 - 2.67 GHz, and the relative bandwidth is 12.3%.

[0079] Figure 8The figure shows the axial ratio curves of the antenna in the embodiments of the present design under different polarizations and different modes. Among the four designed states (State 1, State 2, State 3, and State 4), when the axial ratio of the antenna is less than 3, the common frequency band coverage range of the antenna in the embodiments is: 2.24 - 2.9 GHz, and the relative bandwidth is 25.7%. The axial ratio bandwidth of the antenna in this embodiment is significantly better than that of the orbital angular momentum array antenna composed of existing microstrip patch antennas, proving that the designed antenna has good circular polarization characteristics in different states.

[0080] Figure 9 The figure shows the electric field phase distribution of the reconfigurable orbital angular momentum antenna provided in this embodiment under left-handed circular polarization and OAM mode number +1 (State 1). The electric field phase distribution diagram shows a vortex distribution, and the phase change amount along one circle of the circumference is 2π, and the rotation direction is clockwise, indicating that the present invention generates an OAM beam with mode number l = +1.

[0081] Figure 10 The figure shows the electric field phase distribution of the reconfigurable orbital angular momentum antenna provided in this embodiment under left-handed circular polarization and OAM mode number -1 (State 2). The electric field phase distribution diagram shows a vortex distribution, and the phase change amount along one circle of the circumference is 2π, and the rotation direction is counterclockwise, indicating that the present invention generates an OAM beam with mode number l = -1.

[0082] Figure 11 The figure shows the electric field phase distribution of the reconfigurable orbital angular momentum antenna provided in this embodiment under right-handed circular polarization and OAM mode number +1 (State 3). The electric field phase distribution diagram shows a vortex distribution, and the phase change amount along one circle of the circumference is 2π, and the rotation direction is clockwise, indicating that the present invention generates an OAM beam with mode number l = +1.

[0083] Figure 12 The figure shows the electric field phase distribution of the reconfigurable orbital angular momentum antenna provided in this embodiment under right-handed circular polarization and OAM mode number -1 (State 4). The electric field phase distribution diagram shows a vortex distribution, and the phase change amount along one circle of the circumference is 2π, and the rotation direction is counterclockwise, indicating that the present invention generates an OAM beam with mode number l = -1.

[0084] Figures 13-14 The normalized radiation pattern of the antenna in the embodiment at 2.5 GHz is plotted. The antenna of the present invention is a unidirectional radiation antenna. It can be seen that both State 1 and State 2 are left-handed circular polarization;

[0085] Figures 15-16 The normalized radiation pattern of the antenna in the embodiment at 2.5 GHz is plotted. The antenna of the present invention is a unidirectional radiation antenna. It can be seen that both State 3 and State 4 are right-handed circular polarization;

[0086] An embodiment of the present invention provides a multi-modal composite reconfigurable orbital angular momentum antenna based on a uniform circular array. By changing the on-off states of radio frequency switches on the unit antennas, the switching between four OAM modes and circular polarization can be further realized. The problems of single performance during the reconstruction of vortex electromagnetic waves and complex array feeding network structures are well solved. In addition, an electrically tunable method is adopted in the design, which can greatly improve the accuracy and speed of adjustment during composite reconstruction.

Claims

1. Electrically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna, characterized in that, It includes a first dielectric substrate (1) and a second dielectric substrate (2) arranged successively from bottom to top. A third dielectric substrate is arranged above the second dielectric substrate (2), and an air layer is spaced between the third dielectric substrate and the second dielectric substrate (2); the first dielectric substrate (1) and the second dielectric substrate (2) are both square in shape and of the same size; a metal feeding network (8) is printed on the lower surface of the first dielectric substrate (1), and a metal ground plane (6) in the shape of a square with the same shape and size as it is printed on the upper surface of the first dielectric substrate (1). Four metal radiation patches (4) in the shape of the same size and shape of a ring are printed on the upper surface of the second dielectric substrate (2), and the four metal radiation patches (4) are evenly distributed on the same circumference; the third dielectric substrate includes four circular third dielectric substrate units (3) arranged on the same plane, and the four third dielectric substrate units (3) are respectively located directly above the four metal radiation patches (4), and the four third dielectric substrate units (3) are arranged in one-to-one correspondence with the four metal radiation patches (4); a circular metal coupling patch (5) with the same radius is printed on the lower surface of each of the third dielectric substrate units (3); It further includes four feeding probe units. Each unit includes four evenly distributed feeding probes. Each feeding probe unit successively penetrates the first dielectric substrate (1), the metal ground plane (6), and the second dielectric substrate (2) from bottom to top and then connects the metal radiation patch (4) to the metal feeding network (8). The four feeding probe units are arranged in one-to-one correspondence with the four metal radiation patches (4); The metal feeding network (8) includes four unit antenna feeding networks and an array system feeding network (8-1), and the four unit antenna feeding networks are all connected to the array system feeding network (8-1); the four unit antenna feeding networks are arranged in one-to-one correspondence with the four metal radiation patches (4), the four unit antenna feeding networks are respectively located directly below the four metal radiation patches (4), and every two adjacent unit antenna feeding networks are mirror symmetric. One unit antenna feeding network is connected to one metal radiation patch (4) through one feeding probe unit; The unit antenna feeding network includes a first power divider (15) with a 1-way to 2-way equal-amplitude and in-phase, an isolation resistor (9) is welded between the two output ends of the first power divider (15), and the two output ends of the first power divider (15) are respectively connected with a first T-shaped single-pole double-throw switch and a second T-shaped single-pole double-throw switch with different excitation phases; each feeding probe unit includes four feeding probes (7), the first T-shaped single-pole double-throw switch is connected to the metal radiation patch (4) through two feeding probes (7), and the second T-shaped single-pole double-throw switch is connected to the metal radiation patch (4) through two feeding probes (7); The first T-shaped single-pole double-throw switch includes four PIN RF switches, a first main transmission line, and two first branch transmission lines disposed on the left and right sides of one end of the first main transmission line. The other end of the first main transmission line is connected to one output end of a first power divider (15). There are gaps between the two first branch transmission lines and the end of the first main transmission line, and one PIN RF switch is disposed in one gap. One feeding probe (7) is respectively disposed at a certain gap from the ends of the two first branch transmission lines away from the first main transmission line, and one PIN RF switch is disposed in one gap. The second T-shaped single-pole double-throw switch includes four PIN RF switches, a second main transmission line, and two second branch transmission lines disposed on the left and right sides of one end of the second main transmission line. The other end of the second main transmission line is connected to one output end of the first power divider (15). There are gaps between the two second branch transmission lines and the end of the second main transmission line, and one PIN RF switch is disposed in one gap. One feeding probe (7) is respectively disposed at a certain gap from the ends of the two second branch transmission lines away from the second main transmission line, and one PIN RF switch is disposed in one gap. The phases excited by the two feeding probes (7) connected to the first branch transmission line are the same, and the phases excited by the two feeding probes (7) connected to the second branch transmission line are the same. The phases excited by the two feeding probes (7) connected to the first branch transmission line lag behind the phases excited by the two feeding probes (7) connected to the second branch transmission line by 90 degrees. The feeding network (8-1) of the array system includes a second power divider (16). The two output ends of the second power divider (16) are respectively connected to a third power divider (17). The two output ends of each third power divider (17) are respectively connected to the first power dividers (15) of two unit antenna feeding networks. Isolation resistors (9) are welded to the two output ends of the second power divider (16) and the two output ends of the third power divider (17). The input end on the second power divider (16) is the total feeding port (10).

2. The electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna according to claim 1, wherein The resistance value of the isolation resistor (9) is 100 ohms.

3. The electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna according to claim 1, wherein The first dielectric substrate (1) is made of a square F4B dielectric material with a relative dielectric constant of 3.5 and a thickness of 0.5 mm, and the side length is 185 mm. The second dielectric substrate (2) is made of a square F4B dielectric material with a relative dielectric constant of 3.5 and a thickness of 0.5 mm, and the side length is 185 mm. The third dielectric substrate unit (3) is an FR4 substrate with a radius of 29 mm and a thickness of 1 mm.

4. The electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna according to claim 1, wherein The metal radiation sheet (4) is a circular ring-shaped metal radiation sheet with an outer diameter of 14.5 mm and an inner diameter of 7.4 mm.

5. The electronically tunable circularly polarized composite multi-modal reconfigurable orbital angular momentum antenna according to claim 1, characterized in that, The position of each feeding probe (7) is 11 mm away from the center of the metal radiation sheet (4).

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