Polarization and mode reconfigurable metasurface antenna and unmanned device

Abstract

The application discloses a polarized and mode reconfigurable metasurface antenna and unmanned equipment. The polarized and mode reconfigurable metasurface antenna comprises, from top to bottom, a metasurface layer, a first dielectric substrate, a metalized ground layer, a second dielectric substrate and a feed network layer. The metasurface layer comprises a plurality of metasurface patterns arranged in an array. The metalized ground layer is provided with a cross-shaped hollow slot in the center, and the center of the cross-shaped hollow slot is embedded with a transmission line. Four X-shaped hollow slots are symmetrically arranged at four corners of the cross-shaped hollow slot. A first feed network in the feed network layer is connected with a first antenna port and feeds the metasurface layer through the cross-shaped hollow slot. A second feed network is connected with a second antenna port and feeds the metasurface layer through the four X-shaped hollow slots. A first PIN diode is arranged in the cross-shaped hollow slot, and a second PIN diode is arranged in the four X-shaped hollow slots. The technical scheme of the embodiment of the application provides a polarized and mode reconfigurable metasurface antenna.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and more particularly to a polarization and mode reconfigurable metasurface antenna and unmanned equipment. Background Technology

[0002] With the rapid development of IoT technology, intelligent devices such as drones are increasingly being used in logistics, inspection, disaster relief, and other fields. In these application scenarios, the integration of wireless communication and wireless power transfer technology is particularly important. It enables unmanned intelligent devices to continuously supply power and exchange information during missions. Since no physical connection is required, it can reduce the weight and complexity of the equipment, and improve overall performance and flexibility.

[0003] As a core component of wireless communication and power transfer systems, the performance of antennas directly affects the efficiency of the entire system. However, traditional antennas have fixed radiation modes and polarization characteristics, making them difficult to adapt to complex and ever-changing application environments. In practical applications, different scenarios have different requirements for antenna performance. Point-to-point communication requires directional radiation modes to enhance signal strength and transmission distance; broadcast communication is more suitable for omnidirectional radiation modes; and in wireless power transfer, linear polarization can provide higher energy harvesting efficiency, while circular polarization can effectively resist multipath effects and polarization mismatch, improving communication reliability.

[0004] Currently, reconfigurable antennas exist to meet the needs of different scenarios. However, most existing reconfigurable antennas can only achieve a single function, such as polarization reconfiguration or pattern reconfiguration, making it difficult to simultaneously meet the dual requirements of wireless communication and wireless power transfer. Furthermore, traditional reconfigurable antennas suffer from complex structures, low switching efficiency, and large performance fluctuations under different operating modes, severely hindering their widespread adoption in practical applications. Especially in the field of wireless power transfer, improving energy harvesting efficiency and adapting to different transmission environments are urgent problems to be solved. Summary of the Invention

[0005] This invention provides a polarization and mode reconfigurable metasurface antenna and an unmanned device, and provides a metasurface antenna with four different polarizations and modes reconfigurable.

[0006] In a first aspect, embodiments of the present invention provide a polarization- and mode-reconfigurable metasurface antenna, comprising: The layers arranged from top to bottom are: a metasurface layer, a first dielectric substrate, a metallized ground layer, a second dielectric substrate, and a power supply network layer. The metasurface layer comprises multiple metasurface patterns arranged in an array; The size of the grounding metal covering the metallized grounding layer is greater than or equal to the size of the multiple metasurface patterns set on the metasurface layer. A cross-shaped hollow groove is set in the center of the metallized grounding layer, and a transmission line is embedded in the center of the cross-shaped hollow groove. Four X-shaped hollow grooves are symmetrically set at the four corners of the cross-shaped hollow groove. The power supply network layer includes a first power supply network and a second power supply network. The first power supply network is connected to the first antenna port and feeds the metasurface layer through a cross-shaped cutout. The second power supply network is connected to the second antenna port and feeds the metasurface layer through four X-shaped cutouts. In the cross-shaped hollow slot, a first PIN diode is symmetrically arranged at both ends of one hollow slot, and in the four X-shaped hollow slots, a second PIN diode is symmetrically arranged at both ends of one hollow slot.

[0007] In one possible implementation of the first aspect, when the first PIN diode is turned on, the first feed network excites circularly polarized states to the metasurface layer through a cross-shaped slot, and when the first PIN diode is turned off, the first feed network excites linearly polarized states to the metasurface layer through a cross-shaped slot.

[0008] In one possible implementation of the first aspect, when the second PIN diode is turned on, the second feed network excites circularly polarized states to the metasurface layer through four X-shaped slots; when the second PIN diode is turned off, the second feed network excites linearly polarized states to the metasurface layer through four X-shaped slots.

[0009] In one possible implementation of the first aspect, at least one set of third PIN diodes are symmetrically arranged in the two slots of the cross-shaped cutout, and the at least one set of third PIN diodes is used to adjust the axial ratio of the circular polarization during the polarization of the cross-shaped cutout.

[0010] In one possible implementation of the first aspect, the first power supply network is a transmission line with bent ends, the transmission line with bent ends being located at the position corresponding to the cross-shaped cutout.

[0011] In one possible implementation of the first aspect, the second power supply network is a Wilkinson power divider with four output ports, each corresponding to a position of an X-shaped slot.

[0012] In one possible implementation of the first aspect, the first dielectric substrate and the second dielectric substrate are made of polytetrafluoroethylene.

[0013] In one possible implementation of the first aspect, the multiple metasurface patterns are octagonal structures formed by cutting off the four corners of a square.

[0014] In one possible implementation of the first aspect, the first antenna port and the second antenna port are also connected to the rectifier circuit via an impedance matching network.

[0015] In a second aspect, embodiments of the present invention provide an unmanned device, including a polarization and mode reconfigurable metasurface antenna, a radio frequency module, and an unmanned device body as described in any one of claims 1-9; The main body of the unmanned device is connected to a polarization and mode reconfigurable metasurface antenna via a radio frequency module. The polarization and mode reconfigurable metasurface antenna provides the main body of the unmanned device with wireless signal transmission and reception functions and wireless power transmission functions.

[0016] The polarization and mode reconfigurable metasurface antenna and unmanned device provided in this embodiment include, from top to bottom, a metasurface layer, a first dielectric substrate, a metallized ground layer, a second dielectric substrate, and a feed network layer. The metasurface layer includes multiple metasurface patterns arranged in an array. The size of the grounding metal covering the metallized ground layer is greater than or equal to the size of the multiple metasurface patterns on the metasurface layer. A cross-shaped slot is provided in the center of the metallized ground layer, and a transmission line is embedded in the center of the cross-shaped slot. Four X-shaped slots are symmetrically arranged at the four corners of the cross-shaped slot. The feed network layer includes a first feed network and a second... The antenna has two feed networks. The first feed network is connected to the first antenna port and feeds the metasurface layer through a cross-shaped slot. The second feed network is connected to the second antenna port and feeds the metasurface layer through four X-shaped slots. A first PIN diode is symmetrically arranged at both ends of one slot in the cross-shaped slot. A second PIN diode is symmetrically arranged at both ends of one slot in each of the four X-shaped slots. By adjusting the on / off state of each PIN diode, the entire antenna can switch between four different operating modes, providing a metasurface antenna with reconfigurable polarization and mode. Attached Figure Description

[0017] Figure 1 A side view of a polarization and mode reconfigurable metasurface antenna provided for an embodiment of the present invention; Figure 2 A top view of the metasurface layer of a polarization and mode reconfigurable metasurface antenna provided in an embodiment of the present invention; Figure 3 A top view of the metallized ground layer of a polarization and mode reconfigurable metasurface antenna provided in an embodiment of the present invention; Figure 4 A top view of the feed network layer of a polarization and mode reconfigurable metasurface antenna provided in an embodiment of the present invention; Figure 5a This is a schematic diagram of the current distribution in Mode 1; Figure 5bThis is a schematic diagram of the current distribution in Mode 2; Figure 5c This is a schematic diagram of the current distribution in Mode 3; Figure 5d This is a schematic diagram of the current distribution in Mode 4; Figure 6a This is a schematic diagram of the radiation characteristics of Mode 1; Figure 6b This is a schematic diagram of the radiation characteristics of Mode 2; Figure 6c This is a schematic diagram of the radiation characteristics of Mode 3; Figure 6d This is a schematic diagram of the radiation characteristics of Mode 4; Figure 7a This is a schematic diagram of the magnetic field distribution in Mode 1; Figure 7b This is a schematic diagram of the magnetic field distribution in Mode 2; Figure 7c This is a schematic diagram of the magnetic field distribution in Mode 3; Figure 7d This is a schematic diagram of the magnetic field distribution in Mode 4; Figure 8 A schematic diagram of the PIN diode distribution in the metallized ground layer of a polarization and mode reconfigurable metasurface antenna provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the rectifier circuit in a polarization and mode reconfigurable metasurface antenna provided in an embodiment of this application. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0019] Figures 1 to 4 A schematic diagram of a polarization and mode reconfigurable metasurface antenna provided in an embodiment of the present invention, wherein... Figure 1 This is a side view of a polarization and mode reconfigurable metasurface antenna provided in an embodiment of the present invention. Figure 2 This is a top view of the metasurface layer of a polarization and mode reconfigurable metasurface antenna provided in an embodiment of the present invention. Figure 3 This is a top view of the metallized ground layer of a polarization and mode reconfigurable metasurface antenna according to an embodiment of the present invention. Figure 4 A top view of the feed network layer of a polarization and mode reconfigurable metasurface antenna provided in an embodiment of the present invention, as shown below. Figures 1 to 4 As shown, the polarization and mode reconfigurable metasurface antenna provided in this embodiment of the invention includes: The layers arranged from top to bottom are: metasurface layer 11, first dielectric substrate 12, metallized ground layer 13, second dielectric substrate 14, and power supply network layer 15.

[0020] The metasurface layer 11 includes multiple metasurface patterns 21 arranged in an array; the metallized ground layer 13 has a metal covering with a size greater than or equal to the size of the multiple metasurface patterns 21 on the metasurface layer 11, and a cross-shaped cutout 22 is provided in the center of the metallized ground layer 13. A transmission line is embedded in the center of the cross-shaped cutout 22, and four X-shaped cutouts 23 are symmetrically arranged at the four corners of the cross-shaped cutout 22; the feed network layer 15 includes a first feed network 24 and a second feed network 25. The first feed network 24 is connected to the first antenna port 26 and feeds power to the metasurface layer 11 through the cross-shaped cutout 22, and the second feed network 25 is connected to the second antenna port 27 and feeds power to the metasurface layer 11 through the four X-shaped cutouts 23.

[0021] In the cross-shaped hollow slot 22, a first PIN diode 31 is symmetrically arranged at both ends of one hollow slot, and in the four X-shaped hollow slots 23, a second PIN diode 32 is symmetrically arranged at both ends of one hollow slot in each X-shaped hollow slot.

[0022] To address the issue of fixed radiation modes and polarization characteristics in traditional antennas, the antenna provided in this application embodiment offers an antenna whose radiation modes and polarization characteristics are reconfigurable. Multiple metasurface patterns 21 arrayed on the metasurface layer 11 serve as the unified radiator for the entire antenna. By adjusting the feed network layer 15 and the metallized ground layer 13, the radiation modes and polarization characteristics of the entire antenna can be reconfigured.

[0023] First, a metasurface layer is formed by arranging multiple metasurface patterns 21 in an array on the first dielectric substrate 12. In other words, the antenna provided in this embodiment is a metasurface antenna. A metasurface antenna is an antenna that uses artificial metasurface materials to control the phase, amplitude, and polarization characteristics of electromagnetic waves. Metasurface materials are two-dimensional artificial materials with a thickness less than the wavelength, and the phase, polarization, and propagation mode of electromagnetic waves can be controlled through lateral subwavelength microstructures or uniform films. In this embodiment, an array of multiple identical metasurface patterns 21 constitutes the entire metasurface layer. The shape and size of each metasurface pattern 21 can be designed according to the actual radiation requirements of the antenna. The multiple metasurface patterns 21 arranged in the array are symmetrically positioned with the center of the metasurface layer 11 as the center of symmetry.

[0024] A metallized ground layer 13 is disposed between the first dielectric substrate 12 and the second dielectric substrate 14, and a feed network layer 15 is disposed on the other side of the second dielectric substrate 14. The entire antenna has two antenna ports, a first antenna port 26 and a second antenna port 27 disposed on the feed network layer 15. The first antenna port 26 and the second antenna port 27 are coupled to the metasurface layer 11 through the first feed network 24 and the second feed network 25, respectively. In the metallized ground layer 13 disposed in the first dielectric substrate 12 and the second dielectric substrate 14, the size of the grounded metal covering it is greater than or equal to the size of the plurality of metasurface patterns 21 disposed on the metasurface layer 11. The presence of the metallized ground layer 13 shields the coupling feed of the first feed network 24 and the second feed network 25 to the metasurface layer 11. Therefore, a cutout is disposed on the metallized ground layer 13, corresponding to the feed positions of the first feed network 24 and the second feed network 25, so that the first feed network 24 and the second feed network 25 can feed the metasurface layer 11 through the cutout.

[0025] The metallized grounding layer 11 has a cross-shaped perforated groove 22 formed by two vertical perforated grooves at its center. A transmission line is embedded in the center of each of the two perforated grooves. The transmission lines in the two perforated grooves have the same width but different lengths. The cross-shaped perforated groove 22 corresponds to the center of multiple metasurface patterns 21. Four X-shaped perforated grooves 23 are symmetrically arranged at the four corners of the cross-shaped perforated groove 22, which are also the four corners of the metallized grounding layer 11. Each X-shaped perforated groove 23 consists of two mutually perpendicular perforated grooves. The feeding position of the first feeding network 24 corresponds to the cross-shaped perforated groove 22, and the first feeding network 24 feeds power to the metasurface layer 11 through the cross-shaped perforated groove 22. The second feeding network 25 includes four feeding positions corresponding to the four X-shaped perforated grooves 23, and the second feeding network 25 feeds power to the metasurface layer 11 through the four X-shaped perforated grooves 23.

[0026] To enable reconfigurable radiation modes and polarization characteristics of the entire antenna, first PIN diodes 31 are symmetrically arranged at both ends of one of the cross-shaped slots 22, and second PIN diodes 32 are symmetrically arranged at both ends of one of the four X-shaped slots 23. There are a total of 10 PIN diodes (first PIN diodes 31 and second PIN diodes 32). By controlling the on / off state of the first PIN diodes 31 and second PIN diodes 32, the length of the corresponding slot can be adjusted, thereby changing the radiation mode and polarization characteristics of the entire antenna and achieving reconfigurable radiation modes and polarization characteristics.

[0027] The polarization and mode reconfigurable metasurface antenna provided in this embodiment includes, from top to bottom, a metasurface layer, a first dielectric substrate, a metallized ground layer, a second dielectric substrate, and a feed network layer. The metasurface layer includes multiple metasurface patterns arranged in an array. The size of the grounded metal covering the metallized ground layer is greater than or equal to the size of the multiple metasurface patterns on the metasurface layer. A cross-shaped slot is provided at the center of the metallized ground layer, and a transmission line is embedded in the center of the cross-shaped slot. Four X-shaped slots are symmetrically arranged at the four corners of the cross-shaped slot. The feed network layer includes a first feed network and a second feed network. The antenna has a first feeding network connected to the first antenna port and feeding the metasurface layer through a cross-shaped slot. The second feeding network is connected to the second antenna port and feeding the metasurface layer through four X-shaped slots. A first PIN diode is symmetrically arranged at both ends of one slot in the cross-shaped slot, and a second PIN diode is symmetrically arranged at both ends of one slot in each of the four X-shaped slots. By adjusting the on / off state of each PIN diode, the entire antenna can switch between four different operating modes, providing a metasurface antenna with polarization and mode reconfigurability.

[0028] The first dielectric substrate 12 and the second dielectric substrate 14 can be dielectric substrates of any material, such as polytetrafluoroethylene (PTFE), or they can be flexible dielectric substrates. In this embodiment, the first dielectric substrate 12 and the second dielectric substrate 14 can be made of polytetrafluoroethylene with a dielectric constant of 2.1 and a loss tangent of 0.0002. The thickness of the first dielectric substrate 12 is 2 mm, and the thickness of the second dielectric substrate 14 is 1 mm.

[0029] In this embodiment, the first feed network 24 is a transmission line with bent ends, located at the position corresponding to the cross-shaped cutout 22, that is, the transmission line with bent ends is located at the center of the metallized ground layer 13. The distance between the first antenna port 26 and the transmission line with bent ends is L5, the bending angle of the transmission line with bent ends is α, and the length of the transmission line with bent ends is L6.

[0030] In this embodiment, the second power supply network 25 is a Wilkinson power divider with four output ports, each corresponding to a position in an X-shaped slot 23. The Wilkinson power divider can feed the power of the second antenna port 27 to the metasurface layer 11 through the four X-shaped slots 23 in an equal amplitude and phase manner.

[0031] Among them, the multiple metasurface patterns 21 on the metasurface layer 11 can be octagonal structures formed by cutting off the four corners of a square. The octagonal structure is the closest to a circle among centrally symmetric structures, and its performance stability is higher than that of a square. After cutting off the corners of the square unit structure, the resonant frequency of the octagonal unit is slightly higher than that of the original square unit due to the shortened equivalent electrical length. In this embodiment, the number of metasurface patterns 21 can be 4×4. Four suitable operating modes are extracted from the octagonal patterns, namely Mode 1, Mode 2, Mode 3, and Mode 4, where Mode 1 and Mode 2 are modes with orthogonal current distributions, and Mode 3 and Mode 4 are modes with orthogonal current distributions. Figures 5a-5d As shown, Figures 5a-5d This is a schematic diagram of the current distribution of the metasurface layer in an embodiment of this application. Figure 5a This is a schematic diagram of the current distribution in Mode 1. Figure 5b This is a schematic diagram of the current distribution in Mode 2. Figure 5c This is a schematic diagram of the current distribution in Mode 3. Figure 5d This is a schematic diagram of the current distribution in Mode 4. Figures 6a-6c This is a schematic diagram of the radiation characteristics of the metasurface layer in an embodiment of this application, wherein, Figure 6a This is a schematic diagram of the radiation characteristics of Mode 1. Figure 6b This is a schematic diagram of the radiation characteristics of Mode 2. Figure 6c This is a schematic diagram of the radiation characteristics of Mode 3. Figure 6d This is a schematic diagram of the radiation characteristics of Mode 4.

[0032] In this embodiment, when the antenna operates at a frequency of 2.45 GHz, a 4×4 array of metasurface patterns 21 is used, and the size of the metasurface layer 11 can be 250 mm × 250 mm. In modes 1 and 2, the resonant frequency is 2.45 GHz, and the entire antenna exhibits directional radiation characteristics. In modes 3 and 4, the resonant frequency is 2.5 GHz, and the entire antenna exhibits weighted radiation characteristics.

[0033] In one embodiment, the length and width w of each metasurface pattern 21 in the polarization and mode reconfigurable metasurface antenna provided in this application embodiment are both 44.9 mm, the distance g between adjacent metasurface patterns 21 is 3.5 mm, the length and width of the metasurface layer 11 are 250 mm, the length of L5 is 108.7 mm, the length of L6 is 35.2 mm, and α = 45°.

[0034] To effectively excite the desired modes, both amplitude and direction conditions must be met simultaneously. Both pairs of modes to be excited are TM modes. This means that the feed source needs to be determined based on the magnetic field distribution of each mode on the metasurface. The amplitude can be determined based on the location of the strongest magnetic field distribution, and the direction can be determined based on the direction of the magnetic field distribution. When choosing a direction parallel to the distribution direction, the feed type and structure need to be considered. Figures 7a-7d This is a schematic diagram of the magnetic field distribution of the metasurface layer in an embodiment of this application, wherein, Figure 7a This is a schematic diagram of the magnetic field distribution in Mode 1. Figure 7b This is a schematic diagram of the magnetic field distribution in Mode 2. Figure 7c This is a schematic diagram of the magnetic field distribution in Mode 3. Figure 7d This is a schematic diagram of the magnetic field distribution in Mode 4.

[0035] In this embodiment, the feed structure should simultaneously excite two circular polarization modes. To achieve a directional circular polarization radiation pattern, a pair of orthogonal directional modes, namely mode 1 and mode 2, are required. Figures 7a-7d The magnetic field distribution of the four modes shows that Mode 1 and Mode 2 have the strongest magnetic fields in the same region. Furthermore, the magnetic fields of Mode 1 and Mode 2 are mainly distributed at the very center of the metasurface, and the equivalent magnetic field directions of Mode 1 and Mode 2 are orthogonal in this region. Therefore, using 90° intersecting slots with long and short gaps, Mode 1 and Mode 2 can be excited with a 90° phase difference in the intersecting direction. This produces a circularly polarized directional radiation pattern.

[0036] Similarly, to achieve an omnidirectional circularly polarized radiation pattern, a pair of orthogonal omnidirectional modes are required, namely mode 3 and mode 4. Figures 7a-7d The magnetic field distribution of the four modes shows that modes 3 and 4 have the strongest magnetic fields in the same region. Furthermore, the magnetic fields of modes 3 and 4 are mainly distributed at the four corners of the metasurface, and the equivalent magnetic field directions of modes 3 and 4 are orthogonal in this region. Therefore, by employing a 90° intersecting slit pattern with long and short slits, modes 3 and 4 can be excited laterally with a 90° phase difference, thus achieving a circularly polarized omnidirectional radiation pattern.

[0037] Since linear polarization excitation does not require a 90° phase difference for orthogonal modes, only a symmetrical slotted structure needs to be excited. Therefore, based on two circular polarization feeding structures, the 90° phase difference is weakened, resulting in directional linear polarization and omnidirectional linear polarization, respectively. This is achieved by using PIN diodes in the slots. Specifically, by adjusting the on / off state of the first PIN diode 31 and the second PIN diode 32, the length of the slot containing the diodes can be changed, thus switching between linear and circular polarization. Because the electric field vector of the electromagnetic wave remains in a fixed direction in linear polarization, more concentrated energy transmission can be achieved, making it suitable for wireless power transmission systems. Circular polarization is used in wireless communication because it better resists multipath fading and maintains communication quality. Directional radiation patterns are used to charge objects using specific transmitters, while omnidirectional radiation patterns are used to harvest electromagnetic energy from the environment.

[0038] Specifically, in this embodiment, when the first PIN diode 31 is turned on, the first feed network 24 excites circularly polarized radiation to the metasurface layer 11 through the cross-shaped perforated slot 22; when the first PIN diode 31 is turned off, the first feed network 24 excites linearly polarized radiation to the metasurface layer 11 through the cross-shaped perforated slot 22. When the second PIN diode 32 is turned on, the second feed network 25 excites circularly polarized radiation to the metasurface layer 11 through the four X-shaped perforated slots 23; when the second PIN diode 32 is turned off, the second feed network 25 excites linearly polarized radiation to the metasurface layer 11 through the four X-shaped perforated slots 23.

[0039] Furthermore, at least one set of third PIN diodes 33 are symmetrically arranged in the two slots of the cross-shaped slot 22. The at least one set of third PIN diodes 33 is used to adjust the axial ratio of circular polarization during the polarization radiation of the cross-shaped slot 22. The presence of orthogonal cross-shaped slot coupling in the metallized ground layer 13 does not affect omnidirectional circular polarization and omnidirectional linear polarization, but the axial ratio of circular polarization will become narrower. In order to further maintain the axial ratio performance of omnidirectional circular polarization, at least one set of third PIN diodes 33 can be placed in the center of the cross-shaped slot 22 (the figure shows an example of placing two sets of symmetrical third PIN diodes 33 in each of the two slots of the cross-shaped slot 22).

[0040] Figure 8 A schematic diagram of the PIN diode distribution in the metallization ground layer of a polarization and mode reconfigurable metasurface antenna provided in an embodiment of the present invention, as shown below. Figure 8As shown, a cross-shaped perforated groove 22 is formed in the center of the metallized grounding layer 13. The cross-shaped perforated groove 22 includes two perforated grooves, groove 81 and groove 82. In one embodiment, the lengths of perforated groove 81 and groove 82 are 122.7 mm and 109.4 mm, respectively. X-shaped perforated grooves 23 are formed at the four corners of the metallized grounding layer 13. Each X-shaped perforated groove 23 includes two perforated grooves, groove 83 and groove 84. In one embodiment, the lengths of perforated groove 83 and groove 84 are 46.8 mm and 42.6 mm, respectively.

[0041] The first PIN diode includes two PIN diodes, D1 and D2, which are positioned symmetrically at opposite ends of the slot 81. The distance between the two PIN diodes and the center of the metallization ground layer 13 (i.e., the intersection center of the cross-shaped slot 22) is L1. When the two PIN diodes D1 and D2 are in the "conducting" state, by adjusting the length of L1, two orthogonal field modes with equal amplitude and a 90° phase difference can be generated, thereby obtaining a circularly polarized state. When the two PIN diodes D1 and D2 are switched to the "off" state, their linearly polarized state is excited.

[0042] Similarly, omnidirectional radiation patterns of modes 3 and 4 are achieved through X-shaped slots 23 at the four corners of the metallized ground layer 13. Circular polarization is achieved by utilizing the asymmetry of the arm lengths of the X-shaped slots 23 to generate a phase shift corresponding to each X-shaped slot 23. By appropriately adjusting the length of the X-shaped slots 23, a 90° phase difference can be achieved in the far field. On the other hand, linear polarization is achieved by maintaining symmetrical arm lengths of the X-shaped slots 23. Four pairs of second PIN diodes (D3-D10) are symmetrically placed at both ends of the four pairs of X-shaped slots 23 arms, with each pair of second PIN diodes being L2 away from the center of the X-shaped slot 23. When the four pairs of second PIN diodes are in the "on" state, adjusting the length of L2 generates two orthogonal field modes with equal amplitudes and a 90° phase difference, thus producing circular polarization. When the four pairs of second PIN diodes are in the "off" state, linear polarization is activated.

[0043] Furthermore, the metallized ground layer 13 has orthogonal cross-groove coupling, which does not affect omnidirectional circular polarization and omnidirectional linear polarization, but the axial ratio of circular polarization will be narrowed. In order to further maintain the axial ratio performance of omnidirectional circular polarization, four sets of third PIN diodes, D11-D18, are placed in the center of the cross-shaped slot 22, of which D11-D14 are located in the center of the cross-shaped slot 22, and D15-D18 are located at a distance L3 from the center of the cross-shaped slot 22.

[0044] In this embodiment, each PIN diode can be a BAT15-04W type PIN diode, which has a reverse breakdown voltage of 5V and a forward current of 0.11A. By controlling the on / off state of PIN diodes D1-D10, four operating modes can be switched.

[0045] When the second antenna port 27 is powered and the PIN diodes D1-D10 are turned off, the mode is switched to directional linear polarization. When the second antenna port 27 is powered on, and PIN diodes D1-D2 are turned on while D3-D10 are turned off, the mode is switched to directional circular polarization. When the first antenna port 26 is powered and the PIN diodes D1-D10 are turned off, the mode switches to omnidirectional linear polarization. When the first antenna port 26 is powered, PIN diodes D1-D2 are cut off and D3-D10 are turned on, switching to omnidirectional circular polarization mode.

[0046] Figure 9 A schematic diagram of the rectifier circuit in the polarization and mode reconfigurable metasurface antenna provided in this application embodiment is shown in the figure. The first antenna port and the second antenna port are also connected to the rectifier circuit 92 through an impedance matching network 91. The impedance matching network 91 can consist of a radial stub 93 and a short-circuit stub 94. The radial stub 93 acts as an open-circuit stub, and its angle can be changed to equivalently adjust a variable capacitor. Compared to a quarter-wavelength stub, this configuration can achieve broadband performance. The short-circuit stub 94 is used to cancel the imaginary part of the input impedance, thereby keeping the real part almost constant. The impedance matching network 91 also includes a connecting line 95. The rectifier circuit 92 can consist of two diodes and two capacitors. The two diodes in the rectifier circuit 92 can be SMS7630 Schottky diodes. The SMS7630 Schottky diode has a low bias voltage requirement and can achieve a rectification efficiency of 66.3% at an input power of 1 dBm. The rectifier consisting of impedance matching network 91 and rectifier circuit 92 can be fabricated using RT5880 substrate with a thickness of 0.813mm, dielectric constant of 2.2, and loss tangent of 0.0009. The rectifier consisting of impedance matching network 91 and rectifier circuit 92 can be used for rectifying circularly polarized modes.

[0047] The rectifier circuit 92 is composed of multiple capacitors and diodes, or the impedance matching network 91 can be any type of impedance matching network, which will not be described in detail in the embodiments of this application. The rectifier circuit 92, as shown in the figure, includes a radial stub 93 and a short-circuit stub 94. The polarization and mode reconfigurable metasurface antenna provided in this application integrates four different operating modes into a single antenna structure and designs a corresponding rectifier circuit for the circular polarization mode, effectively overcoming the limitations of traditional antennas. This polarization and mode reconfigurable metasurface antenna not only meets the needs of different communication scenarios but also significantly improves wireless power transmission efficiency, maintaining good performance indicators in all operating states. It provides an efficient and flexible solution for wireless communication and wireless power transmission, and has significant theoretical value and broad application prospects for promoting the development of multifunctional antenna systems and improving the overall performance of wireless systems.

[0048] This application also provides an unmanned device, including a polarization and mode reconfigurable metasurface antenna, a radio frequency module, and an unmanned device body as shown in any of the above embodiments. The unmanned device body is connected to the polarization and mode reconfigurable metasurface antenna via the radio frequency module. The polarization and mode reconfigurable metasurface antenna provides wireless signal transmission and reception functions and wireless power transmission functions for the unmanned device body. By switching between different polarizations and modes of the polarization and mode reconfigurable metasurface antenna shown in the above embodiments, the unmanned device body can use a single antenna to achieve wireless signal transmission and reception and wireless power transmission. The unmanned device can be, for example, a drone, an unmanned vehicle, or a robot.

[0049] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A polarization- and mode-reconfigurable metasurface antenna, characterized in that, include: The layers arranged from top to bottom are: a metasurface layer, a first dielectric substrate, a metallized ground layer, a second dielectric substrate, and a power supply network layer. The metasurface layer comprises multiple metasurface patterns arranged in an array; The size of the grounding metal covered on the metallized grounding layer is greater than or equal to the size of the multiple metasurface patterns set on the metasurface layer. A cross-shaped hollow groove is set in the center of the metallized grounding layer. A transmission line is embedded in the center of the cross-shaped hollow groove. Four X-shaped hollow grooves are symmetrically set at the four corners of the cross-shaped hollow groove. The power supply network layer includes a first power supply network and a second power supply network. The first power supply network is connected to the first antenna port and feeds the metasurface layer through the cross-shaped cutout. The second power supply network is connected to the second antenna port and feeds the metasurface layer through the four X-shaped cutouts. A first PIN diode is symmetrically arranged at both ends of one of the two intersecting arms of the cross-shaped hollow slot, and a second PIN diode is symmetrically arranged at both ends of one of the four X-shaped hollow slots. When the first PIN diode is turned on, the first feed network excites circularly polarized radiation to the metasurface layer through the cross-shaped cutout; when the first PIN diode is turned off, the first feed network excites linearly polarized radiation to the metasurface layer through the cross-shaped cutout. When the second PIN diode is turned on, the second feed network excites circularly polarized states to the metasurface layer through the four X-shaped slots; when the second PIN diode is turned off, the second feed network excites linearly polarized states to the metasurface layer through the four X-shaped slots.

2. The polarization and mode reconfigurable metasurface antenna according to claim 1, characterized in that, At least one set of third PIN diodes are symmetrically arranged in the two slots of the cross-shaped hollow groove. The at least one set of third PIN diodes is used to adjust the axial ratio of the circular polarization when the cross-shaped hollow groove is polarized and radiated.

3. The polarization and mode reconfigurable metasurface antenna according to claim 1, characterized in that, The first power supply network is a transmission line with bent ends, and the transmission line with bent ends is located at the position corresponding to the cross-shaped hollow slot.

4. The polarization and mode reconfigurable metasurface antenna according to claim 1, characterized in that, The second power supply network is a Wilkinson power divider with four output ports, each of which corresponds to the position of an X-shaped slot.

5. The polarization and mode reconfigurable metasurface antenna according to claim 1, characterized in that, The first dielectric substrate and the second dielectric substrate are made of polytetrafluoroethylene.

6. The polarization and mode reconfigurable metasurface antenna according to claim 1, characterized in that, The multiple metasurface patterns are octagonal structures formed by cutting off the four corners of a square.

7. The polarization and mode reconfigurable metasurface antenna according to claim 1, characterized in that, The first antenna port and the second antenna port are also connected to the rectifier circuit through an impedance matching network.

8. An unmanned device, characterized in that, Includes a metasurface antenna with reconfigurable polarization and mode as described in any one of claims 1-7, a radio frequency module, and an unmanned equipment body; The unmanned device body is connected to the polarization and mode reconfigurable metasurface antenna via a radio frequency module. The polarization and mode reconfigurable metasurface antenna provides the unmanned device body with wireless signal transmission and reception functions and wireless power transmission functions.

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