Broadband 1-bit reconfigurable circularly polarized reflective array antenna based on multi-resonant structure

Abstract

The invention discloses a broadband 1-bit reconfigurable circularly-polarized reflective array antenna based on a multi-resonant structure. The broadband 1-bit reconfigurable circularly-polarized reflective array antenna comprises a reconfigurable circularly-polarized reflective functional layer, a circularly-polarized horn antenna and an acrylic support. The reconfigurable circular polarization reflection function layer is formed by periodically arranging M * N circular polarization reflection array antenna units with the same structure according to the interval of 0.4125 lambda 0. The circularly polarized reflective array antenna unit is composed of a radiation layer and a direct current bias layer, the radiation layer comprises a circuit pattern designed based on a multi-resonant structure, a PIN diode, a radiation dielectric layer and a reflection bottom plate, and the direct current bias structure comprises a direct current bias dielectric layer and a direct current bias circuit. 1-bit regulation and control of unit reflection phases can be realized by controlling the on-off states of the four PIN diodes, a + / -60-degree beam scanning function can be realized by adjusting the state of each circularly polarized reflective array antenna unit, and the circularly polarized reflective array antenna can be applied to wireless communication and satellite communication systems.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and further to a broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure in the field of electromagnetic field and microwave technology. The present invention can be used in microwave and millimeter wave frequency bands, and can reflect circularly polarized waves from a feed source with high intensity, and can realize electrical control of the reflected beam direction, and the beam scanning angle can reach ±60°, and is suitable for communication systems such as wireless communication and satellite communication. Background Art

[0002] As a high-gain antenna consisting of a feed antenna and a reflective functional layer, the reflective array antenna is widely used because of its simple structure, low cost, light weight, and high directivity. Compared with the C-band and X-band, the K-band in wireless communication and satellite communication has a shorter wavelength, a smaller device size, is easier to miniaturize, and has more abundant spectrum resources that can be used. It is one of the main frequency bands in satellite communication. In long-distance communication, electromagnetic waves with shorter wavelengths are more susceptible to interference from the ionosphere and rain attenuation effects. Linearly 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 use in long-distance communication systems. The direction of the reflected beam of the traditional passive reflective array antenna is fixed during design and cannot be flexibly adjusted during subsequent use. On this basis, adding adjustable devices such as PIN diodes, varactor diodes, micro-electromechanical systems (MEMS sensors), micromotors, etc. can adjust the reflection phase of the reflective array antenna unit, thereby reconstructing the reflective functional layer. In the above methods, the solution using varactor diodes and micromotors can achieve continuous adjustment of the unit phase and further obtain higher-precision phase compensation, but the control system is relatively complex and more expensive. Compared with PIN diodes, MEMS sensors require higher turn-on voltages, have lower reliability, and are relatively expensive to process. Therefore, PIN diodes are the preferred solution in the design of reconfigurable reflectarray antennas that can take into account multiple factors such as processing costs, design complexity, and working bandwidth.

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

[0004] Southeast University disclosed a 2-bit circularly polarized beam reflectarray antenna operating in the X-band in its patent application "A 2-bit circularly polarized beam electronically scanned reflectarray antenna" (patent application number 202310842233.5, application date 2023.07.11 application publication number CN 117039452 A). The antenna uses 4 pairs of bowtie patches as the main radiation structure, and selects the working patches by controlling the opening and closing of four pairs of PIN diodes to achieve 2-bit controllable adjustment of the reflection phase, and the operating frequency range is 8.6 to 10.7GHz (21.76%). The invention introduces 8 PIN diodes. Although it can achieve a 2-bit control accuracy and obtain a 3-dB gain bandwidth of 21.76%, the antenna still has the disadvantage that the operating frequency is limited by the size of the PIN diode and cannot be extended to higher frequency bands, such as the Ku band and K band.

[0005] Tsinghua University disclosed a dual circular polarization independent scanning reconfigurable reflectarray antenna operating in the Ku band in its patent application "A dual circular polarization independent scanning reconfigurable reflectarray antenna" (invention patent application number 202310558542.X, application date 2023.05.17, application publication number CN 116666978 A). The antenna uses a cross pattern and an arc as the main radiation structure, and reconstructs the current flow path by controlling the opening and closing of four PIN diodes, realizing the design of four effective states. Among them, the rotation angle between state 00 and state 01, and between state 01 and state 10 differ by 90°, and a rotation phase is used in phase control; state 01 increases the length of the microstrip delay line by about half a wavelength on the basis of state 00, introduces a 180° dynamic phase, and the 3-dB gain bandwidth and 3-dB axial ratio bandwidth are 6.1% (16.1 to 17.1GHz) and 4.9%, respectively. The antenna uses both dynamic phase and rotational phase when designing the unit, which can achieve independent control of left-hand circularly polarized waves and right-hand circularly polarized waves. However, the antenna still has shortcomings. Since the dynamic phase is related to the frequency, the introduction of the dynamic phase leads to a narrow unit operating bandwidth, which is not suitable for application scenarios that require 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 prior art and to propose a broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure, aiming to solve the problems of large unit size and narrow antenna working bandwidth caused by multiple PIN diodes while satisfying the wide working bandwidth of the reflectarray antenna through a multi-resonance structure.

[0007] The technical idea for achieving the purpose of the present invention is: the present invention designs a circularly polarized reflective array antenna unit based on a multi-resonant circuit structure composed of an arc circuit pattern, a rectangular circuit pattern, a fan-shaped circuit pattern, and a square circuit pattern. After receiving an electromagnetic wave from free space to form an induced current, the current will flow through different circuit patterns to form multiple current flow paths, and stabilize the phase difference generated by the plane incidence of the TE mode and the TM mode at about 180°. The present invention adopts a combination of an arc circuit pattern and a fan-shaped circuit pattern, which extends the flow path of the induced current to a certain extent, and the equivalent electrical size of the circuit pattern is effectively increased, thereby solving the problem of narrow unit working bandwidth in the prior art and achieving the purpose of miniaturization of the unit. 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, and the phase difference under the two current flow paths can be stabilized at 180° in a wider frequency band, thereby achieving the widening of the unit working bandwidth. The present invention introduces two pairs of PIN diodes, one end of the PIN diode is connected to a reflective bottom plate through a grounding blind hole, and the other end is connected to a DC bias circuit through a DC bias through hole. The DC level input by the DC bias circuit controls the opening and closing of the two pairs of PIN diodes to achieve reconstruction of the reflection phase of the reflectarray antenna unit.

[0008] To achieve the above-mentioned purpose, the antenna of the present invention comprises a reconfigurable circularly polarized reflection functional layer, a circularly polarized horn antenna and an acrylic bracket; the reconfigurable circularly polarized reflection functional layer comprises M×N circularly polarized reflection array antenna units with the same structure, which are periodically arranged at an interval of 0.4125λ0, λ0 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 reflection array antenna unit comprises a radiation layer and a DC bias structure that form a multi-resonance structure based on an arc circuit pattern, a rectangular circuit pattern, and a fan-shaped circuit pattern; when TE mode and TM mode plane waves are incident, a linear polarization reflection phase difference of about 180° is generated; a PIN diode is introduced to control the working state of the circularly polarized reflection array antenna unit (2), and the reconstruction of the circularly polarized reflection functional layer is achieved by regulating the 1-bit reflection phase.

[0009] Compared with the prior art, the present invention has the following advantages:

[0010] First, the present invention designs a circularly polarized reflectarray antenna unit composed of a radiation layer and a DC bias layer, and adopts arc, sector and rectangular design circuit graphics. The combination of arc and sector graphics can form a multi-resonance structure and extend the flow path of the current to a certain extent. The unit equivalent microstrip line length is effectively increased, which overcomes the problem of large unit size caused by the introduction of multiple PIN diodes in the prior art, so that the circularly polarized reflectarray antenna unit designed by the present invention has the advantages of small electrical size and small physical size.

[0011] Second, the present invention can generate a stable linear polarization reflection phase difference when TE mode and TM mode plane waves are incident respectively, so that left-handed / right-handed circularly polarized waves can be reflected with high intensity, and the rotation direction of the electromagnetic wave will not be changed before and after the reflection. The phase control method adopts a rotating phase scheme, and the phase difference between the corresponding units in the two working states can be stabilized at about 180°, thereby achieving the expansion of the working bandwidth. The problem of narrow working bandwidth of the antenna in the prior art is overcome, so that the antenna of the present invention has the advantages of high reflection coefficient, low cross-polarization level, and wide working bandwidth.

[0012] Third, the present invention adopts the form of space feeding to feed, which avoids the large insertion loss caused by the feeding network compared with the phased array antenna. The reflection phase is discretized, and a PIN diode is introduced to control the working state of the reflective array antenna unit. The control function of the working state of a circularly polarized reflective array antenna unit can be completed by only one DC bias, realizing the 1-bit design of the reflection phase, and further realizing the reconstruction of the circularly polarized reflection function layer, so that the present invention has the advantages of simple control method, simple structure, low power consumption and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0014] Figure 2 It is a schematic diagram of the planar structure of the circularly polarized reflectarray antenna unit of the present invention;

[0015] Figure 3 It is a schematic diagram of the three-dimensional structure of the circularly polarized reflectarray antenna unit of the present invention;

[0016] Figure 4 Schematic diagram of an ideal model plane structure when the circularly polarized reflectarray antenna unit of an embodiment of the present invention is in state "0";

[0017] Figure 5 Schematic diagram of an ideal model plane structure when the circularly polarized reflectarray antenna unit of an embodiment of the present invention is in state "1";

[0018] Figure 6 Graph showing simulation results of reflection coefficients of circularly polarized reflectarray antenna units in two states according to an embodiment of the present invention;

[0019] Figure 7 Graph showing the reflection phase simulation results of the circularly polarized reflectarray antenna unit in two states according to an embodiment of the present invention;

[0020] Figure 8 The embodiment of the present invention is a right-hand circular polarization horn feeding beam pointing The gain pattern of the yoz plane when ;

[0021] Fig. 9The embodiment of the present invention is a right-hand circular polarization horn feeding beam pointing When , the gain pattern of the xoz plane;

[0022] Fig.10 The embodiment of the present invention is a right-hand circular polarization horn feeding beam pointing When , the gain and aperture efficiency change with frequency;

[0023] Fig.11 In the embodiment of the present invention, the right-hand circularly polarized horn feeding beam is respectively directed to

[0024] Gain pattern of the xoz plane when . DETAILED DESCRIPTION

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] Reference Figure 1 , the structure of the present invention is further explained.

[0028] The antenna of the present invention comprises a reconfigurable circularly polarized reflection functional layer 1 , a circularly polarized horn antenna 3 and an acrylic bracket 4 .

[0029] The reconfigurable circularly polarized reflective functional layer 1 and the circularly polarized horn antenna 3 are fixed on the acrylic bracket 4 by nylon screws 5 .

[0030] The reconfigurable circularly polarized reflective functional layer 1 is composed of M×N circularly polarized reflective 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 M and N are both positive integers greater than or equal to 1.

[0031] In the embodiment of the present invention, M=20, N=20, the center frequency is 22.5 GHz, and λ0=13.333 mm.

[0032] Reference Figure 2 and 3 , the structure of the circularly polarized reflectarray antenna unit of the present invention is further explained.

[0033] Each circularly polarized reflectarray antenna unit 2 includes two parts, namely, a radiation layer and a DC bias structure, which form a multi-resonance structure based on an arc-shaped circuit pattern, a rectangular circuit pattern, and a fan-shaped circuit pattern, and is fed in the form of space feeding.

[0034] 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 medium layer 46 and a reflective bottom plate 47. The DC bias structure includes a DC bias medium layer 48 and a DC bias circuit 49.

[0035] In the embodiment of the present invention, the thicknesses of the radiation medium layer 46 and the DC bias layer 48 are 0.135λ0 and 0.015λ0 respectively.

[0036] 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 medium layer 46 .

[0037] The first circuit pattern 21, the second circuit pattern 22, the third circuit pattern 23, the fourth circuit pattern 24 are 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, and the fourth circuit pattern 24 are connected to the reflective bottom plate 47 through the first grounding blind via 41, the second grounding blind via 42, the third grounding blind via 43, and the fourth grounding blind via 44, respectively, and the square circuit pattern 25 is connected to the DC bias circuit 49 through the DC bias through hole 45.

[0038] The center 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 the embodiment of the present invention. The center positions of 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 can be expressed as (0.1125λ0, 0), (-0.1125λ0, 0) (0, 0.1125λ0), and (0, -0.1125λ0), and the 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 the 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 connected to the first circuit pattern 21 and the second circuit pattern 22 respectively; the cathodes of the third PIN diode 33 and the fourth PIN diode 34 are connected to the square circuit pattern 25, and the cathodes are connected to the third circuit pattern 23 and the fourth circuit pattern 24 respectively.

[0039] 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 reflected beam direction is adjusted to achieve electrical reconfiguration.

[0040] Reference Figure 4 , the ideal model plane structure of the circularly polarized reflectarray antenna unit of the present invention when it is in state "0" is further described.

[0041] 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 model of the first PIN diode 31 and the second PIN diode 32 is 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 plane 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 connected through the first PIN diode equivalent circuit pattern 54 and the second PIN diode equivalent circuit pattern 55, respectively.

[0042] The first circuit pattern 21 is formed by connecting a first arc circuit pattern 51 through a first rectangular circuit pattern 52 and a first fan-shaped circuit pattern 53. The second circuit pattern 22 is formed by connecting a second fan-shaped circuit pattern 56 through a second rectangular circuit pattern 57 and a second arc circuit pattern 58.

[0043] In the embodiment of the present invention, the center of the first arc 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 circuit pattern 51 is 0° to 90°, and is 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, the radius is 0.15λ0, the angle is 0° to 90°, and is 60° in the embodiment of the present invention, and then subtracted from the equilateral triangle whose three fixed point coordinates are (0, 0), (0.07875λ0, 0.07875λ0 / (3^0.5)) and (-0.07875λ0, 0.07875λ0 / (3^0.5)). The side length of the square circuit figure is 0.1125λ0, and the coordinates of the four vertices are respectively expressed as (0.05625λ0,0), (-0.05625λ0,0), (0, 0.05625,) and (0, -0.05625λ0).

[0044] The second circuit pattern 22 can be obtained by rotating the first circuit pattern 21 by 180° along (0, 0).

[0045] Reference Figure 5 , the ideal model plane structure of the circularly polarized reflectarray antenna unit of the present invention when it is in state "0" is further described.

[0046] When the voltage input to the DC bias circuit is a negative value (-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 case, the equivalent model of the third PIN diode 33 and the fourth PIN diode 34 is a third PIN diode equivalent circuit pattern 64 and a 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 connected through the third PIN diode equivalent circuit pattern 64 and the fourth PIN diode equivalent circuit pattern 65, respectively.

[0047] The third circuit pattern 23 is formed by connecting the third arc-shaped circuit pattern 61 through the third rectangular circuit pattern 62 and the third fan-shaped circuit pattern 63; the fourth circuit pattern 24 is formed by connecting the fourth fan-shaped 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).

[0048] The effect of the present invention is further described below in conjunction with simulation experiments.

[0049] 1. Simulation conditions and contents.

[0050] Simulation experiment 1 of the present invention uses commercial simulation software ANSYS HFSS_2021R1 to model and simulate the present invention, and obtains the reflection coefficient diagram and reflection phase diagram of the circularly polarized reflectarray antenna unit state "0" and state "1", respectively. Figure 6 and Figure 7 shown.

[0051] Simulation experiment 2 of the present invention uses commercial simulation software ANSYS HFSS_2021R1 to model and simulate the present invention, and obtains the present invention in the right-hand circular polarization speaker feeding, the reflected beam pointing When , the gain patterns of the yoz and xoz surfaces are as follows: Figure 8 and Fig. 9 shown.

[0052] Simulation experiment 3 of the present invention uses commercial simulation software ANSYS HFSS_2021R1 to model and simulate the present invention, and obtains the present invention in the right-hand circular polarization speaker feeding, the reflected beam pointing When the gain and aperture efficiency vary with frequency, the relationship between them is shown in the figure below: Fig.10 shown.

[0053] Simulation experiment 4 of the present invention uses commercial simulation software ANSYS HFSS_2021R1 to model and simulate the present invention, and obtains the present invention in the right-hand circular polarization speaker feeding, the reflected beam pointing When , the gain pattern of the xoz plane is as follows: Fig.10 shown.

[0054] 2. Analysis of simulation results:

[0055] Figure 6 It is a reflection coefficient diagram of the circularly polarized reflectarray antenna unit state "0" and state "1" in the present invention. Figure 6 The horizontal axis is the frequency in GHz, and the vertical axis is the reflection coefficient in dB.

[0056] Figure 6The curve marked with a square represents the right-hand circular polarization reflection coefficient curve of the unit corresponding to state "0"; the curve marked with a circle represents the right-hand circular polarization reflection coefficient curve of the unit corresponding to state "1"; the curve marked with an upper triangle represents the left-hand circular polarization reflection coefficient curve of the unit corresponding to state "0"; the curve marked with a lower triangle represents the right-hand circular polarization reflection coefficient curve of the unit corresponding to state "1"; the curve marked with a diamond represents the cross-polarization circular polarization reflection coefficient curve of the unit corresponding to state "0"; the curve marked with a left triangle represents the cross-polarization circular polarization reflection coefficient curve of the unit corresponding to state "1".

[0057] Depend on Figure 6 It can be seen from the curves marked with squares, circles, upper triangles, and lower triangles that the co-polarization and circular polarization reflection coefficients are all greater than -1dB between the frequencies of 19.0GHz and 28.8GHz. Figure 6 It can be seen from the curve marked with the diamond in the middle and the curve marked with the triangle on the left that, between the frequencies of 19.0 GHz and 28.8 GHz, the cross-polarization circular polarization reflection coefficient is less than -10 dB, and the -10 dB cross-polarization bandwidth is 41.34%, which meets the requirement that the unit cross-polarization is less than -10 dB in the working frequency band.

[0058] Figure 7 is the reflection phase diagram of the circularly polarized reflectarray antenna unit state "0" and state "1" in the present invention, Figure 7 The horizontal axis is the frequency in GHz, and the vertical axis is the reflection phase in degrees.

[0059] Figure 7 The curve marked with a square represents the right-hand circular polarization reflection phase curve of the unit corresponding to state "0"; the curve marked with a circle represents the right-hand circular polarization reflection phase curve of the unit corresponding to state "1"; the curve marked with an upper triangle represents the left-hand circular polarization reflection phase curve of the unit corresponding to state "0"; the curve marked with a lower triangle represents the right-hand circular polarization reflection phase curve of the unit corresponding to state "1".

[0060] Depend on Figure 7 From the curves marked with squares and circles, we can see that the right-hand circular polarization reflection phases corresponding to the two states differ by about 180° between 18 GHz and 30 GHz. Figure 7 It can be seen from the curve marked by the upper triangle and the curve marked by the lower triangle that the left-hand circularly polarized reflection phases corresponding to the two states differ by about 180° between 18 GHz and 30 GHz, and change stably within the above frequency band. The curves are relatively flat, meeting the requirement that the reflection phase difference between the two state units within the working frequency band is about 180°.

[0061] Figure 8 and Fig. 9 In the present invention, the right-hand circular polarization horn is fed, and the reflected beam is directed to yoz and xoz surface gain patterns when . Figure 8 and Fig. 9 The horizontal axis is the reflected beam angle θ, in degrees, and the vertical axis is the gain, in dBic.

[0062] Figure 8 and Fig. 9 The black curve in the figure is the gain curve of the right-hand circularly polarized reflected wave, and the gray curve is the gain curve of the left-hand circularly polarized reflected wave.

[0063] Depend on Figure 8 and Fig. 9 From the black curve in , we can see that the maximum value of the right-hand circular polarization reflected beam on the yoz and xoz planes is 22.49dBic, both pointing to θ = 0°, which is consistent with the design direction of the beam. The main polarization of the reflected beam is right-hand circular polarization, which can meet the requirement that the antenna gain is higher than 22dBic. Figure 8 and Fig. 9 It can be seen from the gray curve in that the maximum values ​​of the left-hand circularly polarized reflected beam in the yoz plane and the xoz plane are both less than 2dB, and the cross-polarization of the reflected beam is left-hand circularly polarized, which can meet the requirement that the antenna cross-polarization is less than -20dB.

[0064] Fig.10 In the present invention, the right-hand circular polarization horn is fed, and the reflected beam is directed to The relationship between gain and aperture efficiency at 1000 Hz and frequency. Fig.10 The horizontal axis in is the frequency in GHz, the vertical axis on the left is the gain in dBic, and the vertical axis on the right is the aperture efficiency, which is dimensionless.

[0065] Fig.10 The black curve is the gain, and the gray curve is the aperture efficiency. Fig.10 From the black curve in the figure, we can see that the frequency range of gain greater than 19.49dBic is 19.6GHz to 24GHz, which can meet the requirement that the antenna 3-dB gain bandwidth is greater than 20%. Fig.10 It can be seen from the gray curve in that the frequency range with an aperture greater than 0.15 is 19.8 GHz to 24 GHz, which can meet the requirement that the antenna aperture efficiency is greater than 0.15.

[0066] Fig.11 The invention is a right-hand circular polarization horn feed, the reflected beam points to Gain pattern of the xoz plane when . Fig.11 The horizontal axis is the reflected beam angle θ, in degrees, and the vertical axis is the gain, in dBic.

[0067] Fig.11 The square curve in the figure represents the reflected beam direction. Gain direction curve when ; the curve marked with a circle represents the reflected beam pointing The curve marked with triangles above represents the direction of the reflected beam. The curve marked with a triangle below represents the gain direction curve when Gain direction curve when ; the curve marked with diamonds represents the reflected beam pointing Gain direction curve when .

[0068] Depend on Fig.11 It can be seen from the curve in that the scanning loss of the reflected beam within the scanning angle range of 45° is less than 1.5dB, which can meet the requirement that the beam scanning range is greater than 45°.

[0069] The above simulation results show that, compared with the prior art, the circularly polarized reflectarray antenna unit proposed in the present invention has the characteristics of small point 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 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, λ0 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 reflection array antenna unit (2) comprises two parts, namely, a radiation layer and a DC bias structure, which form a multi-resonance structure based on an arc circuit pattern, a rectangular circuit pattern, and a fan-shaped circuit pattern; when TE mode and TM mode plane waves are incident, a linear polarization reflection phase difference of about 180° is generated; and by controlling the on / off state of four PIN diodes, 1-bit regulation of the unit reflection phase can be achieved.

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) via 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 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 (25), 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).

4. 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).

5. The broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure according to claim 3, characterized in that: 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 a first PIN diode (31), a second PIN diode (32), a third PIN diode (33) and a fourth PIN diode (34); the first circuit pattern (41), the second circuit pattern (42), the third circuit pattern (43) and the fourth circuit pattern (44) are connected respectively to a reflective bottom plate (47) through a first grounding blind hole (41), a second grounding blind hole (42), a third grounding blind hole (43) and a fourth grounding blind hole (44); and the square circuit pattern (25) is connected to a DC bias circuit (49) through a DC bias through hole (45).

6. The broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure according to claim 5, characterized in that: The first circuit pattern (21) is composed of a first arc-shaped circuit pattern (51) connected via a first rectangular circuit pattern (52) and a first fan-shaped circuit pattern (53); the second circuit pattern (22) is composed of a second fan-shaped circuit pattern (56) connected via a second rectangular circuit pattern (57) and a second arc-shaped circuit pattern (58); the third circuit pattern (23) is composed of a third arc-shaped circuit pattern (61) connected via a third rectangular circuit pattern (62) and a third fan-shaped circuit pattern (63); and the fourth circuit pattern (24) is composed of a fourth fan-shaped circuit pattern (66) connected via a fourth rectangular circuit pattern (67) and a fourth arc-shaped circuit pattern (68).

7. The broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure according to claim 4, 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.

8. The broadband 1-bit reconfigurable circularly polarized reflectarray antenna based on a multi-resonance structure according to claim 1, characterized in that: The circularly polarized horn antenna (3) has two polarization modes, namely left-hand circular polarization and right-hand circular polarization, and excites the reconfigurable circularly polarized reflection functional layer (1) in the form of space feeding.

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