Broadband 1-bit Reconfigurable Circularly Polarized Reflectarray Antenna Based on Multi-Resonant Structure

Abstract

The present invention discloses a broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonant structure, which includes a reconfigurable circularly polarized reflection functional layer, a circularly polarized horn antenna, and an acrylic bracket. The reconfigurable circularly polarized reflection functional layer is composed of M×N circularly polarized reflectarray antenna elements with the same structure, which are periodically arranged at an interval of 0.4125λ0. The circularly polarized reflectarray antenna element consists of a radiation layer and a DC bias layer. The radiation layer includes a circuit pattern designed based on a multi-resonant structure, PIN diodes, a radiation dielectric layer, and a reflection bottom plate. The DC bias structure includes a DC bias dielectric layer and a DC bias circuit. By controlling the on-off states of four PIN diodes, 1-bit regulation of the unit reflection phase can be achieved. By adjusting the states of each circularly polarized reflectarray antenna element, a beam scanning function of ±60° can be realized, and it can be applied in wireless communication and satellite communication systems.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technologies, and more particularly to a broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonant structure in the fields of electromagnetic fields and microwave technologies. The present invention can be used in the microwave and millimeter-wave frequency bands, highly reflect circularly polarized waves from a feed source, and can achieve electrical control of the reflection beam direction. The beam scanning angle can reach ±60°, and it is applicable to communication systems such as wireless communication and satellite communication. Background Art

[0002] As a high-gain antenna composed of a feed antenna and a reflective functional layer, a reflectarray antenna is widely used due to its simple structure, low cost, light weight, high directivity, etc. In the K band of wireless communication and satellite communication, compared with the C band and X band, the wavelength is shorter, the device volume is smaller, it is easier to achieve miniaturization, and the available spectrum resources are also more abundant. It is one of the main frequency bands in satellite communication. In long-distance communication, electromagnetic waves with shorter wavelengths are more easily affected by interference such as the ionosphere and rain fade effects. Linear polarized waves are prone to polarization rotation, and polarization mismatch may occur between the transmitting and receiving antennas. In contrast, circularly polarized antennas can better avoid this problem and are more suitable for application in long-distance communication systems. In the design of traditional passive reflectarray antennas, the direction of the reflection beam is fixed and cannot be flexibly adjusted during subsequent use. By adding adjustable devices such as PIN diodes, varactor diodes, micro-electro-mechanical systems (MEMS sensors), and micro-motors on this basis, the reflection phase of the reflectarray antenna unit can be adjusted, and thus the reconstruction of the reflective functional layer can be achieved. Among the above methods, although the schemes using varactor diodes and micro-motors can achieve continuous adjustment of the unit phase and further obtain higher-precision phase compensation, the control system is relatively complex and the cost is higher. MEMS sensors require a higher turn-on voltage than PIN diodes, have lower reliability, and the processing cost is also relatively high. Therefore, PIN diodes are the preferred solution in the design of reconfigurable reflectarray antennas that can take into account multiple factors such as processing cost, design complexity, and working bandwidth.

[0003] Due to the limitations of the number and size of PIN diodes, the operating frequency bands of current reconfigurable circularly polarized reflectarray antennas are mostly designed in the X band and Ku band.

[0004] Southeast University discloses a reflectarray antenna with a 2-bit circularly polarized beam operating in the X-band in its patent document "A 2-bit Circularly Polarized Beam Electrically Scanned Reflectarray Antenna" (Patent Application No. 202310842233.5, Application Date: July 11, 2023, Publication No. CN 117039452 A). This antenna uses 4 pairs of bowtie patches as the main radiation structure, and realizes the 2-bit controllable adjustment of the reflection phase by controlling the on / off of four pairs of PIN diodes to select the working patches. The operating frequency range is 8.6 to 10.7 GHz (21.76%). Although this invention introduces 8 PIN diodes and can achieve a 2-bit regulation accuracy and obtain a 3-dB gain bandwidth of 21.76%, the disadvantage of this antenna is that the operating frequency is limited by the size of the PIN diodes and cannot be extended to higher frequency bands such as the Ku-band and K-band.

[0005] Tsinghua University discloses a reconfigurable reflectarray antenna with dual circular polarization and independent scanning operating in the Ku-band in its patent document "A Dual Circularly Polarized Independently Scanned Reconfigurable Reflectarray Antenna" (Invention Patent Application No. 202310558542.X, Application Date: May 17, 2023, Publication No. CN 116666978 A). This antenna uses a cross pattern and an arc as the main radiation structure, and realizes the reconstruction of the current flow path by controlling the on / off of 4 PIN diodes, achieving the design of four effective states. Among them, the rotation angle between state 00 and state 01, and between state 01 and state 10 differs by 90°, and a rotation phase is adopted in the phase regulation; on the basis of state 00, the length of the microstrip delay line in state 01 increases by about half a wavelength, introducing a 180° dynamic phase. The 3-dB gain bandwidth and 3-dB axial ratio bandwidth are 6.1% (16.1 to 17.1 GHz) and 4.9% respectively. This antenna simultaneously employs dynamic phase and rotation phase in the unit design and can achieve independent regulation of left-handed circularly polarized waves and right-handed circularly polarized waves. However, the disadvantage of this antenna is that due to the dynamic phase being related to frequency, the introduction of the dynamic phase leads to the problem of narrow unit operating bandwidth and is not suitable for application scenarios requiring a wider operating frequency band. Summary of the Invention

[0006] The purpose of the present invention is to address the deficiencies of the above-mentioned existing technologies and propose a broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonant structure, aiming to solve the problems of large unit size and narrow antenna operating bandwidth caused by multiple PIN diodes while meeting the requirement of wide operating bandwidth of the reflectarray antenna through the multi-resonant structure.

[0007] The technical concept for achieving the object of the present invention is as follows: Based on a multi-resonant circuit structure composed of an arc-shaped circuit pattern, a rectangular circuit pattern, a sector-shaped circuit pattern, and a square circuit pattern, the circularly polarized reflectarray antenna element of the present invention is designed. After receiving electromagnetic waves from free space to form an induced current, the current will flow through different circuit patterns, forming multiple current flow paths, and stabilizing the phase difference generated by the TE mode and TM mode plane incidence at about 180°. The present invention adopts a combination of an arc-shaped circuit pattern and a sector-shaped circuit pattern, which extends the flow path of the induced current to a certain extent, effectively increases the equivalent electrical size of the circuit pattern, thereby solving the problem of narrow operating bandwidth of the unit in the prior art and achieving the purpose of unit miniaturization. The circuit pattern of the radiation layer designed by the present invention can form two different current flow paths after two orthogonal plane waves are incident. The phase difference under the two current flow paths can be stabilized at 180° within a wide frequency band, realizing the broadening of the operating bandwidth of the unit. The present invention introduces two pairs of PIN diodes. One end of the PIN diode is connected to the reflective bottom plate through a grounding via, and the other end is connected to the DC bias circuit through a DC bias via. The on-off of the two pairs of PIN diodes is controlled by the DC level input through the DC bias circuit, realizing the reconstruction of the reflection phase of the reflectarray antenna element.

[0008] To achieve the above object, the antenna of the present invention includes a reconfigurable circularly polarized reflection functional layer, a circularly polarized horn antenna, and an acrylic bracket; the reconfigurable circularly polarized reflection functional layer is composed of M×N circularly polarized reflectarray antenna elements with the same structure, which are periodically arranged at an interval of 0.4125λ0, where λ0 is the wavelength at the center frequency of the antenna, and both M and N are positive integers greater than or equal to 1; each circularly polarized reflectarray antenna element includes a radiation layer based on an arc-shaped circuit pattern, a rectangular circuit pattern, and a sector-shaped circuit pattern to form a multi-resonant structure and a DC bias structure; when TE mode and TM mode plane waves are incident, a linear polarization reflection phase difference of about 180° is generated; PIN diodes are introduced to control the working state of the circularly polarized reflectarray antenna element (2), and the reconfiguration of the circularly polarized reflection functional layer is realized through the regulation of 1-bit reflection phase.

[0009] The present invention has the following advantages compared with the prior art:

[0010] First, the present invention designs a circularly polarized reflectarray antenna element composed of a radiation layer and a DC bias layer, and adopts arc-shaped, sector-shaped, and rectangular circuit patterns. The combination of the arc-shaped and sector-shaped patterns can form a multi-resonant structure and extend the current flow path to a certain extent. The equivalent microstrip line length of the unit is effectively increased, overcoming the problem of large unit size caused by introducing multiple PIN diodes in the prior art, making the circularly polarized reflectarray antenna element designed by the present invention have the advantages of small electrical size and small physical size.

[0011] Second, when the plane waves in the TE mode and the TM mode are incident respectively, the present invention can generate a stable linear polarization reflection phase difference, so that the left-handed / right-handed circularly polarized waves can be reflected with high intensity and the rotation direction of the electromagnetic wave remains unchanged before and after reflection. The phase regulation method adopts a rotational phase scheme, and the phase difference between the two working states of the corresponding units can be stably maintained at about 180°, thereby broadening the working bandwidth. It overcomes the problem of narrow working bandwidth of the antennas in the prior art, and endows the antenna of the present invention with the advantages of high reflection coefficient, low cross-polarization level, wide working bandwidth, etc.

[0012] Third, the present invention is fed in the form of spatial feeding. Compared with phased array antennas, it avoids large insertion losses brought by the feeding network. By discretizing the reflection phase and introducing PIN diodes to control the working states of the reflecting array antenna elements, the control function of the working states of one circularly polarized reflecting array antenna element can be completed only through one DC bias, realizing the 1-bit design of the reflection phase, and further realizing the reconstruction of the circularly polarized reflection functional layer, making the present invention have the advantages of simple control method, simple structure, low power consumption and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a schematic structural diagram of the present invention;

[0014] Figure 2 is a schematic plan view of the planar structure of the circularly polarized reflecting array antenna element of the present invention;

[0015] Figure 3 is a schematic three-dimensional structure diagram of the circularly polarized reflecting array antenna element of the present invention;

[0016] Figure 4 is a schematic plan view of the ideal model planar structure of the circularly polarized reflecting array antenna element of the present invention in state "0" in an embodiment;

[0017] Figure 5 is a schematic plan view of the ideal model planar structure of the circularly polarized reflecting array antenna element of the present invention in state "1" in an embodiment;

[0018] Figure 6 is a simulation result diagram of the reflection coefficients of two states of the circularly polarized reflecting array antenna element of the present invention in an embodiment;

[0019] Figure 7 is a simulation result diagram of the reflection phases of two states of the circularly polarized reflecting array antenna element of the present invention in an embodiment;

[0020] Figure 8 is the gain pattern in the yoz plane when the beam of the right-handed circularly polarized horn in the embodiment of the present invention is fed and the beam direction (θ, φ) = (0°, 0°);

[0021] Figure 9This is the gain pattern in the xoz plane when the beam direction of the right - hand circularly polarized horn feed in the embodiment of the present invention is (θ, φ) = (0°, 0°).

[0022] Figure 10 This is the curve graph of the relationship between the gain and aperture efficiency and frequency when the beam direction of the right - hand circularly polarized horn feed in the embodiment of the present invention is (θ, φ) = (0°, 0°).

[0023] Figure 11 These are the gain patterns in the xoz plane when the beam directions of the right - hand circularly polarized horn feed in the embodiment of the present invention are respectively (θ, φ) = (0°, 0°), (θ, φ) = (15°, 0°), (θ, φ) = (30°, 0°), (θ, φ) = (45°, 0°), (θ, φ) = (60°, 0°). Detailed implementation manners

[0024] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0025] Refer to Figure 1 to further illustrate the structure of the present invention.

[0026] The antenna of the present invention includes a reconfigurable circularly polarized reflection functional layer 1, a circularly polarized horn antenna 3, and an acrylic bracket 4.

[0027] The reconfigurable circularly polarized reflection functional layer 1 and the circularly polarized horn antenna 3 are fixed on the acrylic bracket 4 by nylon screws 5.

[0028] The reconfigurable circularly polarized reflection functional layer 1 is composed of M×N circularly polarized reflection array antenna units with the same structure, which are periodically arranged at an interval of 0.4125λ0, where λ0 is the wavelength at the center frequency of the antenna, and both M and N are positive integers greater than or equal to 1.

[0029] In the embodiment of the present invention, M = 20, N = 20, the center frequency is 22.5 GHz, and λ0 = 13.333 mm.

[0030] Refer to Figure 2 and 3 to further illustrate the structure of the circularly polarized reflection array antenna unit of the present invention.

[0031] Each circularly polarized reflection array antenna unit 2 includes a radiation layer and a DC bias structure that form a multi - resonance structure based on an arc - shaped circuit pattern, a rectangular circuit pattern, and a sector - shaped circuit pattern, and is fed in a form of space feeding.

[0032] The radiation layer includes a first circuit pattern 21, a second circuit pattern 22, a third circuit pattern 23, a fourth circuit pattern 24, a square circuit pattern 25, a first PIN diode 31, a second PIN diode 32, a third PIN diode 33, a fourth PIN diode 34, a radiation dielectric layer 46, and a reflection bottom plate 47. The DC bias structure includes a DC bias dielectric layer 48 and a DC bias circuit 49.

[0033] In an embodiment of the present invention, the thicknesses of the radiation dielectric layer 46 and the DC bias layer 48 are 0.135λ0 and 0.015λ0 respectively.

[0034] The first circuit pattern 21, the second circuit pattern 22, the third circuit pattern 23, the fourth circuit pattern 24, and the square circuit pattern 25 are printed on the upper surface of the radiation dielectric layer 46.

[0035] The first circuit pattern 21, the second circuit pattern 22, the third circuit pattern 23, the fourth circuit pattern 24 are respectively connected to the square circuit pattern 25 through the first PIN diode 31, the second PIN diode 32, the third PIN diode 33, and the fourth PIN diode 34. The first circuit pattern 21, the second circuit pattern 22, the third circuit pattern 23, the fourth circuit pattern 24 are respectively connected to the reflection bottom plate 47 through the first ground blind hole 41, the second ground blind hole 42, the third ground blind hole 43, and the fourth ground blind hole 44. The square circuit pattern 25 is connected to the DC bias circuit 49 through a DC bias through hole 45.

[0036] The central positions of the first PIN diode 31, the second PIN diode 32, the third PIN diode 33, and the fourth PIN diode 34 can be expressed as (0.0675λ0, 0), (-0.0675λ0, 0), (0, 0.0675λ0), and (0, -0.0675λ0) in an embodiment of the present invention. The center positions of the first ground blind hole 41, the second ground blind hole 42, the third ground blind hole 43, and the fourth ground blind hole 44 can be expressed as (0.1125λ0, 0), (-0.1125λ0, 0), (0, 0.1125λ0), and (0, -0.1125λ0), and their diameters are all 0.015λ0. The DC bias through hole 45 is located at the center of the square circuit pattern 25, which can be expressed as (0, 0), and its diameter is 0.015λ0. The anodes of the first PIN diode 31 and the second PIN diode 32 are connected to the square circuit pattern 25, and the cathodes are respectively connected to the first circuit pattern 21 and the second circuit pattern 22; the cathodes of the third PIN diode 33 and the fourth PIN diode 34 are connected to the square circuit pattern 25, and the anodes are respectively connected to the third circuit pattern 23 and the fourth circuit pattern 24.

[0037] The DC bias circuit 49 has two modes: positive voltage and negative voltage. When a positive voltage is input, the first PIN diode 31 and the second PIN diode 32 are in the on state, and the third PIN diode 33 and the fourth PIN diode 34 are in the off state. At this time, the working state of the circularly polarized reflectarray antenna element 2 is "0". When a negative voltage is input, the first PIN diode 31 and the second PIN diode 32 are in the off state, and the third PIN diode 33 and the fourth PIN diode 34 are in the on state. At this time, the working state of the circularly polarized reflectarray antenna element 2 is "1". By controlling the working state of each circularly polarized reflectarray antenna element 2 in the reconfigurable circularly polarized reflection functional layer 1, the reflection beam direction is regulated to achieve electrical reconfiguration.

[0038] Referring to Figure 4 , the ideal model planar structure of the circularly polarized reflectarray antenna element of the present invention in the state of "0" will be further described.

[0039] When the voltage input to the DC bias circuit is positive (+1.33V), the first PIN diode 31 and the second PIN diode 32 are turned on, and the third PIN diode 33 and the fourth PIN diode 34 are turned off. In an ideal case, the equivalent models of the first PIN diode 31 and the second PIN diode 32 are the first PIN diode equivalent circuit pattern 54 and the second PIN diode equivalent circuit pattern 55. At this time, the circuit pattern of the ideal model planar structure is composed of the first circuit pattern 21, the second circuit pattern 22, the first PIN diode equivalent circuit pattern 54, the second PIN diode equivalent circuit pattern 55, and the square circuit pattern 25. The first circuit pattern 21, the second circuit pattern 22, and the square circuit pattern 25 are respectively connected through the first PIN diode equivalent circuit pattern 54 and the second PIN diode equivalent circuit pattern 55.

[0040] The first circuit pattern 21 is formed by connecting the first arc circuit pattern 51 through the first rectangular circuit pattern 52 and the first sector circuit pattern 53. The second circuit pattern 22 is formed by connecting the second sector circuit pattern 56 through the second rectangular circuit pattern 57 and the second arc circuit pattern 58.

[0041] In an embodiment of the present invention, the center of the first arc-shaped circuit pattern 51 is located at the center of the square circuit pattern 25, which is represented by (0, 0) in the plane rectangular coordinate system. The inner diameter and the outer diameter are 0.165λ0 and 0.18λ0 respectively in this embodiment. The angle of the first arc-shaped circuit pattern 51 ranges from 0° to 90°, and takes 40° in the embodiment of the present invention. The center of the first sector pattern 53 is located at the center of the square circuit pattern 25, with a radius of 0.15λ0. The angle ranges from 0° to 90°, and takes 60° in the embodiment of the present invention, and is obtained by subtracting an equilateral triangle with three fixed-point coordinates (0, 0), (0.07875λ0, 0.07875λ0 / (3^0.5)), and (-0.07875λ0, 0.07875λ0 / (3^0.5)) respectively. The side length of the square circuit pattern is 0.1125λ0, and the coordinates of the four vertices are respectively represented as (0.05625λ0, 0), (-0.05625λ0, 0), (0, 0.05625), and (0, -0.05625λ0).

[0042] The second circuit pattern 22 can be obtained by rotating the first circuit pattern 21 by 180° along (0, 0).

[0043] Referring to Figure 5 , the ideal model plane structure of the circularly polarized reflectarray antenna element of the present invention in the state of "0" will be further described.

[0044] When the voltage input to the DC bias circuit is negative (-1.33V), the third PIN diode 33 and the fourth PIN diode 34 are turned on, and the first PIN diode 31 and the second PIN diode 32 are turned off. In an ideal situation, the equivalent models of the third PIN diode 33 and the fourth PIN diode 34 are the third PIN diode equivalent circuit pattern 64 and the fourth PIN diode equivalent circuit pattern 65. At this time, the circuit pattern of the ideal model plane structure is composed of the third circuit pattern 23, the fourth circuit pattern 24, the third PIN diode equivalent circuit pattern 64, the fourth PIN diode equivalent circuit pattern 65, and the square circuit pattern 25. The third circuit pattern 23, the fourth circuit pattern 24 and the square circuit pattern 25 are respectively connected through the third PIN diode equivalent circuit pattern 64 and the fourth PIN diode equivalent circuit pattern 65.

[0045] The third circuit pattern 23 is composed of connecting the third arc-shaped circuit pattern 61 through the third rectangular circuit pattern 62 and the third sector circuit pattern 63; the fourth circuit pattern 24 is composed of connecting the fourth sector circuit pattern 66 through the fourth rectangular circuit pattern 67 and the fourth arc-shaped circuit pattern 68. The third circuit pattern 23 and the fourth circuit pattern 24 can be obtained by rotating the first circuit pattern 21 counterclockwise by 90° and 270° respectively along (0, 0).

[0046] The effects of the present invention will be further described below in combination with simulation experiments.

[0047] 1. Simulation conditions and content.

[0048] For Simulation Experiment 1 of the present invention, the commercial simulation software ANSYS HFSS_2021R1 is used to model and simulate the present invention, and the reflection coefficient diagrams and reflection phase diagrams of the circularly polarized reflectarray antenna element of the present invention in state "0" and state "1" are obtained, as shown in Figure 6 and Figure 7 respectively.

[0049] For Simulation Experiment 2 of the present invention, the commercial simulation software ANSYS HFSS_2021R1 is used to model and simulate the present invention, and the gain pattern diagrams in the yoz plane and xoz plane are obtained when the present invention is fed by a right-handed circularly polarized horn and the reflection beam points to (θ, φ) = (0°, 0°), as shown in Figure 8 and Figure 9 respectively.

[0050] For Simulation Experiment 3 of the present invention, the commercial simulation software ANSYS HFSS_2021R1 is used to model and simulate the present invention, and the relationship diagram of gain and aperture efficiency varying with frequency is obtained when the present invention is fed by a right-handed circularly polarized horn and the reflection beam points to (θ, φ) = (0°, 0°), as shown in Figure 10 respectively.

[0051] For Simulation Experiment 4 of the present invention, the commercial simulation software ANSYS HFSS_2021R1 is used to model and simulate the present invention, and the gain pattern diagrams in the xoz plane are obtained when the present invention is fed by a right-handed circularly polarized horn and the reflection beam points to (θ, φ) = (0°, 0°), (θ, φ) = (15°, 0°), (θ, φ) = (30°, 0°), (θ, φ) = (45°, 0°), (θ, φ) = (60°, 0°), as shown in Figure 10 respectively.

[0052] 2. Analysis of simulation results:

[0053] Figure 6 is the reflection coefficient diagram of the circularly polarized reflectarray antenna element of the present invention in state "0" and state "1". Figure 6 In, the abscissa is frequency, with the unit of GHz, and the ordinate is the reflection coefficient, with the unit of dB.

[0054] Figure 6The curves marked with squares represent the right - hand circular polarization reflection coefficient curves of the units corresponding to state "0"; the curves marked with circles represent the right - hand circular polarization reflection coefficient curves of the units corresponding to state "1"; the curves marked with upward triangles represent the left - hand circular polarization reflection coefficient curves of the units corresponding to state "0"; the curves marked with downward triangles represent the right - hand circular polarization reflection coefficient curves of the units corresponding to state "1"; the curves marked with diamonds represent the cross - polarization circular polarization reflection coefficient curves of the units corresponding to state "0"; the curves marked with left - hand triangles represent the cross - polarization circular polarization reflection coefficient curves of the units corresponding to state "1".

[0055] From Figure 6 the curves marked with squares, circles, upward triangles and downward triangles in, it can be seen that between the frequencies of 19.0 GHz and 28.8 GHz, the co - polarization circular polarization reflection coefficients are all greater than - 1 dB. From Figure 6 the curves marked with diamonds and left - hand triangles in, it can be seen that between the frequencies of 19.0 GHz and 28.8 GHz, the cross - polarization circular polarization reflection coefficients are less than - 10 dB, and the - 10 dB cross - polarization bandwidth is 41.34%, meeting the requirement that the cross - polarization of the unit is less than - 10 dB within the working frequency band.

[0056] Figure 7 are the reflection phase diagrams of the circular polarization reflectarray antenna unit in state "0" and state "1" of the present invention, Figure 7 in which the abscissa is the frequency, with the unit of GHz, and the ordinate is the reflection phase, with the unit of °.

[0057] Figure 7 The curves marked with squares represent the right - hand circular polarization reflection phase curves of the units corresponding to state "0"; the curves marked with circles represent the right - hand circular polarization reflection phase curves of the units corresponding to state "1"; the curves marked with upward triangles represent the left - hand circular polarization reflection phase curves of the units corresponding to state "0"; the curves marked with downward triangles represent the right - hand circular polarization reflection phase curves of the units corresponding to state "1".

[0058] From Figure 7 the curves marked with squares and circles in, it can be seen that the right - hand circular polarization reflection phases corresponding to the two states differ by approximately 180° between 18 GHz and 30 GHz. From Figure 7 the curves marked with upward triangles and downward triangles in, it can be seen that the left - hand circular polarization reflection phases corresponding to the two states differ by approximately 180° between 18 GHz and 30 GHz, and are stable within the above - mentioned frequency band, with the curves being relatively flat, meeting the requirement that the reflection phase difference between the two - state units is about 180° within the working frequency band.

[0059] Figure 8 andFigure 9 In the present invention, when the right-handed circularly polarized horn is used for feeding and the reflection beam points to (θ, φ) = (0°, 0°), these are the gain pattern diagrams in the yoz and xoz planes. Figure 8 and Figure 9 The abscissa of is the reflection beam angle θ, with the unit of °, and the ordinate is the gain, with the unit of dBic.

[0060] Figure 8 and Figure 9 In and, the black curve is the gain curve of the right-handed circularly polarized reflected wave, and the gray curve is the gain curve of the left-handed circularly polarized reflected wave.

[0061] From Figure 8 and Figure 9 From the black curve in and, it can be seen that the maximum values of the right-handed circularly polarized reflection beam in the yoz plane and the xoz plane are 22.49 dBic, both pointing to θ = 0°, which is consistent with the designed pointing of the beam. The main polarization of the reflection beam is right-handed circular polarization, which can meet the requirement that the antenna gain is higher than 22 dBic. From Figure 8 and Figure 9 From the gray curve in and, it can be seen that the maximum values of the left-handed circularly polarized reflection beam in the yoz plane and the xoz plane are both less than 2 dB. The cross polarization of the reflection beam is left-handed circular polarization, which can meet the requirement that the antenna cross polarization is less than -20 dB.

[0062] Figure 10 This is the curve graph of the variation of the gain and aperture efficiency with frequency when the right-handed circularly polarized horn is used for feeding and the reflection beam points to (θ, φ) = (0°, 0°) in the present invention. Figure 10 In, the abscissa is the frequency, with the unit of GHz, the left ordinate is the gain, with the unit of dBic, and the right ordinate is the aperture efficiency, dimensionless.

[0063] Figure 10 In, the black curve is the gain and the gray curve is the aperture efficiency. From Figure 10 From the black curve in, it can be seen that the frequency range where the gain is greater than 19.49 dBic is from 19.6 GHz to 24 GHz, which can meet the requirement that the 3-dB gain bandwidth of the antenna is greater than 20%. From Figure 10 From the gray curve in, it can be seen that the frequency range where the aperture is greater than 0.15 is from 19.8 GHz to 24 GHz, which can meet the requirement that the aperture efficiency of the antenna is greater than 0.15.

[0064] Figure 11 This is the gain pattern diagram in the xoz plane when the right-handed circularly polarized horn is used for feeding and the reflection beam points to (θ, φ) = (0°, 0°), (θ, φ) = (15°, 0°), (θ, φ) = (30°, 0°), (θ, φ) = (45°, 0°), (θ, φ) = (60°, 0°) in the present invention.Figure 11 The abscissa is the reflection beam angle θ, with the unit of °, and the ordinate is the gain, with the unit of dBic.

[0065] Figure 11 The curve marked with a square in represents the gain direction curve when the reflection beam points to (θ, φ) = (60°, 0°); the curve marked with a circle represents the gain direction curve when the reflection beam points to (θ, φ) = (45°, 0°); the curve marked with an upward triangle represents the gain direction curve when the reflection beam points to (θ, φ) = (30°, 0°); the curve marked with a downward triangle represents the gain direction curve when the reflection beam points to (θ, φ) = (15°, 0°); the curve marked with a diamond represents the gain direction curve when the reflection beam points to (θ, φ) = (0°, 0°).

[0066] From Figure 11 the curves in, it can be seen that the scanning loss of the reflection beam within the scanning angle range of 45° is less than 1.5 dB, which can meet the requirement of the beam scanning range being greater than 45°.

[0067] The above simulation results show that compared with the prior art, the circularly polarized reflectarray antenna element proposed by the present invention has the characteristics of small dot size, small physical size, high reflection coefficient, and wide working bandwidth. The antenna of the present invention has the characteristics of simple structure, simple control method, low power consumption, and low cross-polarization level.

Claims

1. A broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure, comprising a reconfigurable circularly polarized reflective functional layer (1), a circularly polarized horn antenna (3) and an acrylic bracket (4); characterized in that: The reconfigurable circularly polarized reflective functional layer (1) comprises M×N circularly polarized reflective array antenna units of the same structure, arranged in a manner of 0.4125 λ 0 is arranged periodically. λ 0 is the wavelength at the antenna center frequency, and M and N are both positive integers greater than or equal to 1; each circularly polarized reflectarray antenna unit (2) comprises a radiation layer and a DC bias structure based on an arc circuit pattern, a rectangular circuit pattern, and a fan-shaped circuit pattern to form a multi-resonance structure; a linear polarization reflection phase difference of 180° is generated when TE mode and TM mode plane waves are incident; 1-bit control of the unit reflection phase can be achieved by controlling the on / off state of four PIN diodes; the radiation layer comprises a first circuit pattern (21), a second circuit pattern (22), a third circuit pattern (23), a fourth circuit pattern (24), a square circuit pattern (2 5), a first PIN diode (31), a second PIN diode (32), a third PIN diode (33), a fourth PIN diode (34), a radiation medium layer (46) and a reflective bottom plate (47); the first circuit pattern (21), the second circuit pattern (22), the third circuit pattern (23), the fourth circuit pattern (24) and the square circuit pattern (25) are connected respectively through the first PIN diode (31), the second PIN diode (32), the third PIN diode (33) and the fourth PIN diode (34); the first circuit pattern (21), the second circuit pattern (22), the third circuit pattern (23), the fourth circuit pattern (24) and the square circuit pattern (25) The pattern (23) and the fourth circuit pattern (24) are connected to the reflective bottom plate (47) through the first grounding blind hole (41), the second grounding blind hole (42), the third grounding blind hole (43), and the fourth grounding blind hole (44), respectively; the square circuit pattern (25) is connected to the DC bias circuit (49) through the DC bias through hole (45); the first circuit pattern (21) is composed of a first arc-shaped circuit pattern (51) connected through a first rectangular circuit pattern (52) and a first fan-shaped circuit pattern (53); the second circuit pattern (22) and the second fan-shaped circuit pattern (56) are connected through a second rectangular circuit pattern (57) and a second arc-shaped circuit pattern (58); The second circuit pattern (22) can be obtained by rotating the first circuit pattern (21) by 180 degrees along (0, 0); the third circuit pattern (23) is formed by connecting a third arc-shaped circuit pattern (61) through a third rectangular circuit pattern (62) and a third fan-shaped circuit pattern (63); the fourth circuit pattern (24) is formed by connecting a fourth fan-shaped circuit pattern (66) through a fourth rectangular circuit pattern (67) and a fourth arc-shaped circuit pattern (68); the third circuit pattern (23) and the fourth circuit pattern (24) can be obtained by rotating the first circuit pattern (21) counterclockwise by 90 degrees and 270 degrees respectively along (0, 0).

2. The broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure according to claim 1, characterized in that: The reconfigurable circularly polarized reflective functional layer (1) and the circularly polarized horn antenna (3) are fixed on the acrylic bracket (4) by means of nylon screws (5).

3. The broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure according to claim 1, characterized in that: The DC bias structure comprises a DC bias dielectric layer (48) and a DC bias circuit (49).

4. The broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure according to claim 3, characterized in that: The DC bias circuit (49) has two modes: positive voltage and negative voltage. When a positive voltage is input, the first PIN diode (31) and the second PIN diode (32) are in an on state, and the third PIN diode (33) and the fourth PIN diode (34) are in an off state. At this time, the working state of the circularly polarized reflectarray antenna unit (2) is "0". When a negative voltage is input, the first PIN diode (31) and the second PIN diode (32) are in an off state, and the third PIN diode (33) and the fourth PIN diode (34) are in an on state. At this time, the working state of the circularly polarized reflectarray antenna unit (2) is "1". By controlling the working state of each circularly polarized reflectarray antenna unit (2) in the reconfigurable circularly polarized reflective functional layer (1), the direction of the reflected beam is regulated to achieve electrical reconfiguration.

5. The broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure according to claim 3, characterized in that: The DC bias circuit (49) has two modes: positive voltage and negative voltage. When a positive voltage is input, the first PIN diode (31) and the second PIN diode (32) are in an on state, and the third PIN diode (33) and the fourth PIN diode (34) are in an off state. At this time, the working state of the circularly polarized reflectarray antenna unit (2) is "0". When a negative voltage is input, the first PIN diode (31) and the second PIN diode (32) are in an off state, and the third PIN diode (33) and the fourth PIN diode (34) are in an on state. At this time, the working state of the circularly polarized reflectarray antenna unit (2) is "1". By controlling the working state of each circularly polarized reflectarray antenna unit (2) in the reconfigurable circularly polarized reflective functional layer (1), the direction of the reflected beam is regulated to achieve electrical reconfiguration.

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