A multifunctional pattern and polarization independent reconfigurable antenna

Abstract

The application aims to provide a multifunctional pattern and polarization independent reconfigurable antenna, and belongs to the technical field of reconfigurable antennas. The antenna is reconfigurable by designing a reconfigurable unit and a matching reconfigurable feed network, so that the reconfigurable antenna can reconfigure in a 360-degree range in the azimuth plane and the elevation plane, realizing three-dimensional full-space coverage. The on / off of the PIN diode is controlled by direct current feeding, thereby controlling the pattern and polarization independent reconfiguration of the antenna, and the method is simple. The reconfigurable antenna can realize three pattern modes and five polarization independent reconfigurations, a total of twelve radiation states, and the working frequency bands of the twelve radiation states are 2.3GHz-2.75GHz, the return loss is less than-10dB, the impedance bandwidth is more than 17.8%, and the reconfigurable antenna can be applied to various working scenes.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of reconfigurable antennas, and particularly relates to a multifunctional pattern and polarization independent reconfigurable antenna. BACKGROUND

[0002] A reconfigurable antenna is a new type of antenna. Compared with a conventional antenna, the reconfigurable antenna can change its electrical performance characteristics through electrical control, mechanical control, magnetic control, optical control and the like. Therefore, multiple radio application equipment can be integrated on a carrier platform formed by a single antenna, the compatibility between the antenna and a wireless communication system is enhanced, multiple antennas arranged in a limited space are avoided, and the system weight and design complexity are reduced. According to different reconfiguration targets, the reconfigurable antenna can be divided into single-target reconfiguration types such as frequency reconfiguration, polarization reconfiguration and pattern reconfiguration, and multi-target reconfiguration types such as frequency-polarization reconfiguration, polarization-pattern reconfiguration, frequency-pattern reconfiguration and frequency-polarization-pattern reconfiguration. In order to be suitable for more complex and diverse application scenarios, meet the application requirements of reconfiguring a pattern under a specific polarization state and reconfiguring a polarization under a specific pattern state, and exhibit the unique advantages of the reconfigurable antenna, the reconfigurable antenna develops towards multifunctional and independently adjustable.

[0003] Z. Wang et al. (Z. Wang, S. Liu, and Y. Dong, "Low-Profile Metasurface-Based Antenna With Tripolarization for 5G Applications," IEEE Transactions on Antennas and Propagation, vol. 69, no. 9, pp. 5437-5445, 2021) proposed a three-polarization multi-state pattern reconfigurable antenna. By switching the feed port and the radiation surface, three linear polarization modes and two pattern modes of wide-side forward radiation and conical forward radiation can be realized. However, the polarization mode and the pattern state of this antenna are still few, and the antenna pattern can only be reconfigured in the elevation plane. In addition, when the pattern mode of the antenna changes, the polarization mode also changes, and the polarization mode and the pattern mode cannot be independently controllable, which limits the application scenarios.

[0004] W.Li et al. (W.Li, YMWang, Y.Hei, B.Li, and X.Shi, "A Compact Low-Profile Reconfigurable Metasurface Antenna With Polarization and Pattern Diversities," IEEE Antennas and Wireless Propagation Letters, vol.20, no.7, pp.1170-1174, 2021) designed a polarization-pattern reconfigurable antenna based on the switching principle. By switching the feed network and parasitic stripes, they achieved pattern reconstruction under three polarization modes: vertical polarization, horizontal polarization, and circular polarization. However, the reconfigurable range of the antenna pattern is still limited, and 360° reconstruction cannot be achieved simultaneously in the elevation and azimuth planes. Moreover, the antenna pattern state changes with the switching of polarization modes, and the antenna is relatively large, which is not conducive to the design and fabrication of integrated systems.

[0005] Existing technologies include other reconfigurable antennas, but they all suffer from problems such as insufficient reconfigurable states and lack of independent control. Therefore, the design of a multi-functional pattern and polarization-independent reconfigurable antenna has practical significance and application value. Summary of the Invention

[0006] To address the problems existing in the background technology, the purpose of this invention is to provide a multifunctional pattern and polarization-independent reconfigurable antenna. This antenna, through the design of reconfigurable elements and a matching reconfigurable feed network, enables the antenna of this invention to achieve reconfigurability of three pattern modes and five polarization states, and the reconfiguration of pattern and polarization are independent of each other. At the same time, the antenna of this invention has a simple structure, is easy to install, and can be applied to various electromagnetically complex scenarios.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] A multi-functional pattern and polarization-independent reconfigurable antenna includes four identical reconfigurable elements 1, a reconfigurable feed network 2, and four coaxial cables 3;

[0009] The reconfigurable unit comprises a single-layer dielectric plate and metal patterns arranged on the upper and lower surfaces of the single-layer dielectric plate; the first metal pattern arranged on the upper surface of the single-layer dielectric plate comprises four identical L-shaped branches 4 and a first square metal patch 5; two L-shaped branches are a group and are not connected to each other, forming a rectangular shape, and the two rectangles are centrally symmetric about the center point of the first square metal patch; the four edges of the first square metal patch are respectively connected to one end of the adjacent L-shaped branch through a PIN diode 10, and the branch arms of the L-shaped branches adjacent to the first square metal patch are respectively connected to one end of an inductor 11, and the other end of the two inductors connected to the two L-shaped branches in the same group is connected to a bonding pad through a straight wire 7; the second metal pattern arranged on the lower surface of the single-layer dielectric plate also comprises four identical L-shaped branches 4 and a second square metal patch 6, wherein two L-shaped branches are a group and form a rectangular shape, and the two rectangles are centrally symmetric about the center point of the second square metal patch, the two L-shaped branches in the same group are not connected at one end and are connected to the four edges of the second square metal patch at the other end; the two rectangles in the first metal pattern and the two rectangles in the second metal pattern together form a square shape.

[0010] The four reconfigurable units are sequentially and vertically arranged to form a rectangular parallelepiped shape with a closed periphery and an upper and lower opening, and the reconfigurable feeding network is horizontally arranged at the center position of the rectangular parallelepiped; the coaxial cable 3 is used to connect the input end of the reconfigurable unit and the output end of the reconfigurable feeding network, wherein the center of the reconfigurable unit is the input end thereof;

[0011] The reconfigurable feed network 2 comprises a metal ground layer, a dielectric substrate and a metal circuit layer, wherein the metal circuit layer and the metal ground layer are arranged on the upper and lower surfaces of the dielectric substrate; the metal circuit layer is composed of three identical Wilkinson power dividers 12, two reference microstrip lines 13 and two phase-shift microstrip lines 14, each Wilkinson power divider comprising one input end and two output ends; one PIN diode 19 is connected to each output end of the first Wilkinson power divider, the input end of the second Wilkinson power divider and the input end of the third Wilkinson power divider; one side of the first output end of the first Wilkinson power divider and one side of the input end of the second Wilkinson power divider are connected to the first reference microstrip line 13 through a PIN diode, and the other side of the first output end of the first Wilkinson power divider and the other side of the input end of the second Wilkinson power divider are connected to the first phase-shift microstrip line 14 through a PIN diode; one side of the second output end of the first Wilkinson power divider and one side of the input end of the third Wilkinson power divider are connected to the second reference microstrip line 13 through a PIN diode, and the other side of the second output end of the first Wilkinson power divider and the other side of the input end of the third Wilkinson power divider are connected to the second phase-shift microstrip line 14 through a PIN diode; meanwhile, a capacitor 15 is arranged in the middle of the input microstrip line of the first Wilkinson power divider for DC isolation, an inductor 17 is arranged on one of the output microstrip lines of the first Wilkinson power divider for AC isolation, and an inductor 17 and a resistor 18 are arranged in series on the input microstrip lines of the second Wilkinson power divider and the third Wilkinson power divider for AC isolation and voltage division; the output ports of the second Wilkinson power divider and the third Wilkinson power divider serve as four output ports of the reconfigurable feed network 2 and are connected to one end of the coaxial cable 3.

[0012] Further, two L-shaped stubs and a second square metal patch in different groups of the second metal pattern and located on the same straight line form a reflector 20, and two L-shaped stubs located on the same side of the square shape form an electric dipole 9, that is, the reconfigurable unit comprises four electric dipoles 9 and two reflectors 20; by switching the on-off state of the PIN diode 10 in the first metal pattern, only one electric dipole and one reflector participate in work, that is, only one PIN diode is in an open state at a time, and the current on the L-shaped stub connected thereto forms a path, and the electric dipole formed thereby and the reflector parallel thereto participate in work, and the other electric dipoles and reflectors do not participate in work, thereby forming different directionally-oriented Yagi-like antennas.

[0013] Further, the Yagi-like antennas participating in work on each reconfigurable unit are combined to realize the reconfiguration of the directional diagrams of three different modes of broadside forward, back and end-fire.

[0014] Further, by switching the state of PIN diode 19 in reconfigurable feed network 2, the network feed path is switched, different feed phases are output, and five kinds of polarization state reconfiguration are realized.

[0015] Further, the pattern reconfiguration and the polarization state reconfiguration are independent of each other, and the reconfigurable antenna has twelve radiation states in common.

[0016] Further, all PIN diodes in the reconfigurable antenna are SMP1345, and the PIN diodes, inductors and capacitors are all 0402 packages.

[0017] Further, grooves are arranged on both sides and in the middle of the single-layer dielectric plate of reconfigurable unit 1, for connection and fixation between the reconfigurable units and between the reconfigurable units and reconfigurable feed network 2.

[0018] Further, the overall size of the reconfigurable antenna is 0.49λ0*0.49λ0*0.39λ0, λ0 is the operating wavelength at the center frequency point of the antenna, and the size of the reconfigurable unit is 0.39λ0*0.39λ0*0.0007λ0.

[0019] Further, the side lengths of the first metal patch and the second metal patch are different, and are designed according to the operating frequency and impedance matching of the antenna.

[0020] Further, the lengths of the two branch arms of the L-shaped branch are not equal, and the sum of the lengths of the two branch arms is preferably one quarter of the operating wavelength.

[0021] The mechanism of the present application is that each reconfigurable unit of the present application can be regarded as four different-directional Yagi-like antennas, by switching the state of the PIN diode in the first metal pattern, only one Yagi-like antenna in each reconfigurable unit can work. According to the multiplication principle of antenna array factors, the Yagi-like antennas participating in the work on each reconfigurable unit are switched and combined freely, and the pattern can be reconfigured among three modes of broadside (upward Yagi-like antenna participating in work), backfire (downward Yagi-like antenna participating in work) and end-fire (left and right Yagi-like antennas participating in work).

[0022] The application realizes polarization reconstruction by switching the feeding network path. By switching the state of the PIN diode, the reference microstrip line and the phase shift microstrip line participating in the work on the feeding path are changed, so that the feeding network can be switched between four combinations of feeding output phases, which are: (1) 0°, 0°, 0°, 0°; (2) 0°, 0°, 90°, 90°; (3) 0°, 0°, -90°, 90°; (4) 0°, 0°, 180°, 180°. The corresponding antenna polarization modes are: (1) +45° horizontal linear polarization / vertical polarization (+45°HP / VP); (2) left-handed circular polarization (LHCP); (3) right-handed circular polarization (RHCP); (4) -45° horizontal linear polarization / vertical polarization (-45°HP / VP).

[0023] In addition, because the means of pattern reconstruction and polarization reconstruction are different, that is, the pattern reconstruction under the same polarization mode is realized by switching the class-Yagi antenna participating in the work on the reconfigurable unit without changing the feeding network, and the polarization reconstruction under the same pattern mode is realized by switching the feeding network path without changing the class-Yagi antenna participating in the work on the reconfigurable unit, therefore, the pattern reconstruction and the polarization reconstruction can be controlled and realized independently, so that the antenna can be switched and reconstructed between twelve radiation states. They are: S1 (Broadside, -45°HP), S2 (Backfire, -45°HP), S3 (Broadside, 45°HP), S4 (Backfire, +45°HP), S5 (Broadside, LHCP), S6 (Backfire, LHCP), S7 (Broadside, RHCP), S8 (Backfire, RHCP), S9 (+45°End-fire, VP), S10 (-45°End-fire, VP), S11 (+135°End-fire, VP), S12 (-135°End-fire, VP).

[0024] In summary, because the above technical solutions are adopted, the application has the following advantages:

[0025] 1. The reconfigurable antenna of the application can reconstruct the pattern in the range of 360° in the azimuth plane and the elevation plane, and realize three-dimensional full-space coverage; and the on / off of the PIN diode is controlled by direct current feeding, and then the pattern and polarization of the antenna are independently reconfigurable, and the realization means is simple.

[0026] 2.The multifunctional pattern and polarization independent reconfigurable antenna can realize three pattern diagrams and five polarization independent reconfigurable modes, a total of twelve radiation states, and the common working frequency band of the twelve radiation states is 2.3GHz-2.75GHz, the return loss is less than-10dB, the impedance bandwidth is more than 17.8%, and the multifunctional pattern and polarization independent reconfigurable antenna can be applied to various working scenes, such as Internet of Things (IoT), unmanned aerial vehicle communication and the like.

[0027] 3.The multifunctional pattern and polarization independent reconfigurable antenna comprises four reconfigurable units and a reconfigurable feeding network, and the reconfigurable units and the reconfigurable feeding network are realized by printed PCB boards, so that the multifunctional pattern and polarization independent reconfigurable antenna has low cost and simple processing; the overall size of the multifunctional pattern and polarization independent reconfigurable antenna is 0.49λ0*0.49λ0*0.39λ0, the overall size of the reconfigurable unit is 0.39λ0*0.39λ0*0.0007λ0, and the multifunctional pattern and polarization independent reconfigurable antenna has obvious miniaturization advantages; and the reconfigurable unit is less than half a wavelength, so that the multifunctional pattern and polarization independent reconfigurable antenna can be used for phased array. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 FIG. 1 is a schematic diagram of the overall structure of the multifunctional pattern and polarization independent reconfigurable antenna.

[0029] Figure 2 FIG. 4 is a schematic diagram of the structure of the reconfigurable unit in the antenna.

[0030] Figure 3 FIG. 6 is a schematic diagram of the structure of the reconfigurable unit Yagi antenna in the antenna.

[0031] Figure 4 FIG. 8 is a schematic diagram of the structure of the reconfigurable feeding network in the antenna.

[0032] Figure 5 FIG. 11 is a simulation result diagram of the return loss of the antenna in the embodiment.

[0033] Figure 6 FIG. 14 is a simulation result diagram of the 3D pattern of the antenna at the center frequency point under different radiation states in the embodiment.

[0034] Figure 7 FIG. 17 is a simulation result diagram of the peak actual gain of the antenna under different radiation states in the working frequency band in the embodiment.

[0035] Figure 8 FIG. 20 is a simulation result diagram of the radiation efficiency of the antenna under different radiation states in the working frequency band in the embodiment. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is described in further detail below in combination with embodiments and drawings.

[0037] A multifunctional pattern and polarization independent reconfigurable antenna has an overall structure as shown in FIG. 1. Figure 1As shown, it includes four identical reconfigurable units 1, a reconfigurable power supply network 2, and four coaxial cables 3; the four reconfigurable units 1 are arranged vertically in sequence to form a cuboid shape that is closed on all sides and open at the top and bottom, and the reconfigurable power supply network 2 is arranged horizontally at the center of the cuboid; one end of the coaxial cable 3 is connected to the input end of the reconfigurable unit 1 (the center of the second square metal patch), and the other end is connected to the output end of the reconfigurable power supply network 2.

[0038] The structural diagram of the reconfigurable unit 1 is shown below. Figure 2 As shown, it includes a single-layer dielectric substrate and metal patterns disposed on the upper and lower surfaces of the single-layer dielectric substrate; wherein, the first metal pattern located on the upper surface of the single-layer dielectric substrate includes four identical L-shaped branches 4 and a first square metal patch 5; wherein, two L-shaped branches form a group and are not connected to each other, forming a rectangular shape, and the two rectangles are centrally symmetrical about the center point of the first square metal patch; the four sides of the first square metal patch are respectively connected to the adjacent end of the L-shaped branch through a PIN diode 10, and the branch arms of the L-shaped branches adjacent to the first square metal patch are respectively connected to one end of the inductor 11, and the two L-shaped branches in the same group are connected to each other. The other ends of the two inductors connected by the joint are connected to the pads via straight wires 7. Preferably, the pads are located on the lower surface of the single-layer dielectric substrate. The second metal pattern located on the lower surface of the single-layer dielectric substrate also includes four identical L-shaped branches 4 and a second square metal patch 6. The two L-shaped branches form a rectangular shape as a group. The two rectangles are centrally symmetrical about the center point of the second square metal patch. One end of the two L-shaped branches in the same group is not connected, and the other end is connected to the four sides of the second square metal patch respectively. The two rectangles in the first metal pattern and the two rectangles in the second metal pattern together form a large square shape.

[0039] Figure 3 This is a schematic diagram of the Yagi-like antenna configuration in the reconfigurable antenna unit of the present invention. The Yagi-like antenna includes a reflector and an electric dipole. Two L-shaped stub arms and a second square metal patch located on the same straight line in different groups of the second metal pattern constitute a reflector 20. Two L-shaped stub arms located on the same side of the large square constitute an electric dipole 9. Therefore, the reconfigurable unit consists of four electric dipoles 9 and two reflectors 20. By switching the switching state of the PIN diode 10 in the first metal pattern, only one electric dipole and one reflector can operate, forming Yagi-like antennas with different orientations. The Yagi-like antennas operating in each reconfigurable unit are combined to achieve three different types of pattern reconstruction: broadside forward radiation, backfire, and endfire. For example, broadside forward radiation means that an upward-facing Yagi-like antenna is operating.

[0040] The structural schematic diagram of the reconfigurable feeder network 2 is shown below. Figure 4 As shown, the system includes a metal ground plane, a dielectric substrate, and a metal circuit layer, wherein the metal circuit layer and the metal ground plane are disposed on the upper and lower surfaces of the dielectric substrate, respectively. The metal circuit layer consists of three identical Wilkinson power dividers 12, two reference microstrip lines 13, and two phase-shifting microstrip lines 14. Each Wilkinson power divider includes one input terminal and two output terminals. A PIN diode 19 is connected to both sides of each output terminal of the first Wilkinson power divider, both sides of each input terminal of the second Wilkinson power divider, and both sides of each input terminal of the third Wilkinson power divider. One side of the first output terminal of the first Wilkinson power divider and one side of the input terminal of the second Wilkinson power divider are connected to the first reference microstrip line 13 via PIN diodes. The other side of the first output terminal of the first Wilkinson power divider and the other side of the input terminal of the second Wilkinson power divider are connected to the first phase-shifting microstrip line 14 via PIN diodes. The second output terminal of the first Wilkinson power divider and the input terminal of the third Wilkinson power divider are connected to the second reference microstrip line 13 via PIN diodes. The other side of the second output terminal of the first Wilkinson power divider and the other side of the input terminal of the third Wilkinson power divider are connected to the second phase-shifting microstrip line 14 via PIN diodes. Meanwhile, a capacitor 15 is placed in the middle of the input microstrip line of the first Wilkinson power divider to isolate DC, and an inductor 17 is set on one of the output microstrip lines of the first Wilkinson power divider to isolate AC. An inductor 17 and a resistor 18 are connected in series on the input microstrip lines of the second and third Wilkinson power dividers to isolate AC and divide voltage. The output ports of the second and third Wilkinson power dividers serve as the four output ports of the reconfigurable feed network 2, and are respectively connected to one end of the coaxial cable 3.

[0041] By switching the states of the PIN diodes in the reconfigurable feed network 2, the phases of the reference microstrip lines and the phase-shifted microstrip lines participating in the work on the feed path change. For example, when only two reference lines participate in the work, the feed phase is 0°, 0°, 0°, 0°, and the antenna is located at +45° linear polarization or vertical polarization (VP) (related to the Yagi-like antenna participating in the work); when only two phase-shifted lines work, the feed phase is 0°, 0°, -90°, 90°, and the antenna is located at left-handed circular polarization. The reconfigurable feed network can switch between four combinations of feed output phases, which are: (1) 0°, 0°, 0°, 0°; (2) 0°, 0°, 90°, 90°; (3) 0°, 0°, -90°, 90°; (4) 0°, 0°, 180°, 180°. The corresponding antenna polarization modes are: (1) +45° horizontal linear polarization / vertical polarization (+45° HP / VP); (2) left-handed circular polarization (LHCP); (3) right-handed circular polarization (RHCP); (4) -45° horizontal linear polarization / vertical polarization (-45° HP / VP).

[0042] Embodiment 1

[0043] In this embodiment, the overall size of the multifunctional pattern and polarization independent reconfigurable antenna is 57mm x 57mm x 45mm (0.49λ0x 0.49λ0x 0.39λ0); the model of the single-layer dielectric plate in the reconfigurable unit is F4RBM, the thickness is 0.8mm, the size is 57mm x 45mm, the dielectric constant is 4.4, and the loss tangent is 0.0025; the length of the first metal arm in the L-shaped branch is l1=17.8mm, the length of the second metal arm is l2=18mm, the width of the metal arm is w=2.8mm, the side length of the first metal square patch is w1=4mm, the side length of the second metal square patch is w2=10mm, and the width of the thin straight wire is 0.2mm; the model of the four PIN diodes in the reconfigurable unit is SMP1345, and the inductance value of the inductor connected to the L-shaped branch arm is 47nH.

[0044] The model of the dielectric substrate in the reconfigurable feed network is F4RBM, the thickness is 0.508mm, the size is 57mm x 57mm, the dielectric constant is 3.5, and the loss tangent is 0.0025; the width of the Wilkinson power divider 50-ohm microstrip line is 1.14mm, the width of the 70.7-ohm matching line is 0.62mm, the characteristic impedance of the reference microstrip line and the phase-shifted microstrip line is 50 ohm, the length of the reference microstrip line is 28mm and 56mm respectively, and the length of the phase-shifted microstrip line is 56mm and 84mm respectively.

[0045] The above-mentioned sizes are specific sizes after calculation and optimization. If the sizes are changed, the performance of the embodiment of the application will deteriorate.

[0046] The reconfigurable antenna of the embodiment is simulated and tested. Figure 5 Figure 6 is a simulation result diagram of the return loss of the antenna in the embodiment of the application. As can be seen from the figure, the return loss of the antenna in the twelve radiation states is less than -10 dB in the range of 2.3 GHz-2.75 GHz, and the impedance bandwidth is more than 17.8%, which is a wide bandwidth and suitable for various scenarios, such as Internet of Things (IoT), unmanned aerial vehicle communication, etc.

[0047] Figure 6 Figure 7 is a simulation result diagram of the 3D pattern of the antenna in different radiation states at the center frequency point in the embodiment of the application. As can be seen from the figure, the pattern in different polarization modes has strong stability at the center frequency point f=2.6 GHz, that is, the pattern of the antenna does not have large deformation in different polarization modes (for example, S1, S3, S5 and S7 are wide-side-up radiation modes in different polarization modes, and the pattern of the antenna does not have deformation), and the antenna can realize omnidirectional switching in the azimuth plane and the elevation plane at the same time.

[0048] Figure 7 Figure 8 is a simulation result diagram of the peak gain of the antenna in different radiation states in the working frequency band in the embodiment of the application. As can be seen from the figure, the maximum actual gain of the antenna in different radiation modes is more than 3.5 dBi at the center frequency point f=2.6 GHz, and the peak actual gain of the antenna is more than 2 dBi in the whole working frequency band. Figure 8 Figure 9 is a simulation result diagram of the radiation efficiency of the antenna in different radiation states in the working frequency band in the embodiment of the application. As can be seen from the figure, the maximum radiation efficiency of the antenna in different radiation modes is more than 80% at the center frequency point f=2.6 GHz, and the radiation efficiency of the antenna is more than 65% in the whole working frequency band.

[0049] As can be seen, the antenna of the application can realize various radiation states by switching the Yagi-like antenna participating in work on the reconfigurable unit and switching the path of the reconfigurable feeding network; at the same time, the polarization and the pattern are independently reconfigurable, and the three-dimensional full space is covered.

[0050] The above is only a specific implementation of the application, and any feature disclosed in the specification can be replaced by other equivalent or similar purpose alternative features unless specifically described; all features disclosed, or steps in all methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A multi-functional pattern and polarization independently reconfigurable antenna, characterized in that, The reconfigurable antenna comprises four identical reconfigurable units, a reconfigurable feed network and four coaxial cables. The reconfigurable unit comprises a single-layer dielectric plate and metal patterns arranged on the upper and lower surfaces of the single-layer dielectric plate; the first metal pattern arranged on the upper surface of the single-layer dielectric plate comprises four identical L-shaped branches and a first square metal patch; two L-shaped branches are a group and are not connected with each other, forming a rectangular shape, and the two rectangles are centrally symmetric about the center point of the first square metal patch; the four edges of the first square metal patch are respectively connected with one end of the adjacent L-shaped branch through a PIN diode, and the branch arms of the L-shaped branches adjacent to the first square metal patch are respectively connected with one end of an inductor, the other end of the two inductors connected with the two L-shaped branches of the same group is connected with a bonding pad through a straight wire; the second metal pattern arranged on the lower surface of the single-layer dielectric plate also comprises four identical L-shaped branches and a second square metal patch, wherein two L-shaped branches are a group and form a rectangular shape, and the two rectangles are centrally symmetric about the center point of the second square metal patch, one end of the two L-shaped branches of the same group is not connected, and the other end is connected with the four edges of the second square metal patch; the two rectangles in the first metal pattern and the two rectangles in the second metal pattern jointly form a square shape; The four reconfigurable units are sequentially and vertically arranged to form a rectangular parallelepiped shape with a closed periphery and an upper and lower opening, and the reconfigurable feed network is horizontally arranged at the center position of the rectangular parallelepiped; the coaxial cables are used to connect the input end of the reconfigurable unit and the output end of the reconfigurable feed network, wherein the center of the reconfigurable unit is the input end thereof. The reconfigurable feed network comprises a metal ground layer, a dielectric substrate and a metal circuit layer, wherein the metal circuit layer and the metal ground layer are arranged on the upper and lower surfaces of the dielectric substrate; the metal circuit layer is composed of three identical Wilkinson power dividers, two reference microstrip lines and two phase-shift microstrip lines, each Wilkinson power divider comprises one input end and two output ends; one PIN diode is connected to each output end of the first Wilkinson power divider, the input end of the second Wilkinson power divider and the input end of the third Wilkinson power divider; one side of the first output end of the first Wilkinson power divider and one side of the input end of the second Wilkinson power divider are connected to the first reference microstrip line through a PIN diode, and the other side of the first output end of the first Wilkinson power divider and the other side of the input end of the second Wilkinson power divider are connected to the first phase-shift microstrip line through a PIN diode; one side of the second output end of the first Wilkinson power divider and one side of the input end of the third Wilkinson power divider are connected to the second reference microstrip line through a PIN diode, and the other side of the second output end of the first Wilkinson power divider and the other side of the input end of the third Wilkinson power divider are connected to the second phase-shift microstrip line through a PIN diode; meanwhile, a capacitor is arranged in the middle of the input microstrip line of the first Wilkinson power divider for isolating direct current, an inductor is arranged on one of the output microstrip lines of the first Wilkinson power divider for isolating alternating current, and an inductor and a resistor are arranged in series on the input microstrip lines of the second Wilkinson power divider and the third Wilkinson power divider for isolating alternating current and voltage division; the output ports of the second Wilkinson power divider and the third Wilkinson power divider serve as four output ports of the reconfigurable feed network and are connected to one end of a coaxial cable, respectively. Two L-shaped stub arms and a second square metal patch in different groups of the second metal pattern and located on the same straight line form a reflector, and two L-shaped stub arms located on the same side of the square shape form an electric dipole, and the reconfigurable units collectively form four electric dipoles and two reflectors; by switching the on-off state of the PIN diode in the first metal pattern, only one electric dipole and one reflector participate in work, thereby forming different directionally-oriented Yagi-like antennas.

2. The multi-functional pattern and polarization independent reconfigurable antenna according to claim 1, wherein, The Yagi-like antennas participating in work on each reconfigurable unit are combined to realize the reconfiguration of the directional patterns of three different modes of wide-side forward, backward and end-fire.

3. The multi-functional pattern and polarization independent reconfigurable antenna according to claim 1, wherein, By switching the state of the PIN diode in the reconfigurable feed network, the feed path of the network is switched, different feed phases are output, and five polarization state reconfigurations are realized.

4. The multi-functional pattern and polarization independent reconfigurable antenna according to claim 1, wherein, The directional pattern reconfiguration and the polarization state reconfiguration are independent of each other, and the reconfigurable antenna has twelve radiation states in total.

5. The multi-functional pattern and polarization independent reconfigurable antenna according to claim 1, wherein, The models of all the PIN diodes in the reconfigurable antenna are SMP1345, and the PIN diodes, inductors and capacitors all adopt 0402 packaging.

6. The multi-functional pattern and polarization independent reconfigurable antenna according to claim 1, wherein, Grooves are arranged on both sides and in the middle of the single-layer dielectric plate of the reconfigurable unit for connection and fixation between the reconfigurable units and between the reconfigurable units and the reconfigurable feed network.

7. The multi-functional pattern and polarization independent reconfigurable antenna according to claim 1, wherein, The overall size of the reconfigurable antenna is , is the operating wavelength at the center frequency of the antenna, and the size of the reconfigurable unit is .

8. The multi-functional pattern and polarization independent reconfigurable antenna according to claim 1, wherein, The side length of the first metal patch and the second metal patch is different, and is designed according to the working frequency and impedance matching of the antenna; the lengths of the two branch arms of the L-shaped branch are not equal, and the sum of the lengths of the two branch arms is one quarter of the working wavelength.

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