An ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces

Abstract

This invention relates to the field of electromagnetics, specifically to an ultra-wideband, fully polarized, large-angle beam scanning method based on electromagnetic metasurfaces, comprising the following steps: S1, adjusting the far-field phase of the beam based on the array's global reference phase; S2, achieving fully polarized beam control by adjusting the superposition of far-field orthogonal polarized vector fields based on array factors; S3, theoretical calculation verification and full-wave simulation verification of the fully polarized beam control. This invention proposes a novel fully polarized beam control theory based on the superposition of orthogonal polarized vector fields adjusted by array factors, and verifies the effectiveness and versatility of this theory in achieving ultra-wideband, large-angle fully polarized beam control using only one bit of phase resolution through theoretical calculations and full-wave simulations.

Description

Technical Field

[0001] This invention relates to the field of electromagnetics, specifically to an ultrawideband, fully polarized, large-angle beam scanning method based on electromagnetic metasurfaces. Background Technology

[0002] The polarization of electromagnetic waves (EM) is described by the trajectory of its electric field vector direction changing over time. In practical applications, the operating polarization of the receiving antenna must match the polarization of the incident electromagnetic wave to maximize the reception of the information carried by the signal. For example, satellite communication uses circularly polarized antennas, while base station antennas operate using linear polarization. In the radar field, electromagnetic wave polarization can be used for target identification, target detection, and super-resolution imaging. In terms of anti-jamming, advanced polarization manipulation techniques can be applied to radome design, electronic interference suppression and protection, and electromagnetic compatibility. Given these wide range of applications, the realization of electromagnetic wave polarization manipulation has attracted widespread attention from researchers. Metasurfaces are planar artificial electromagnetic structures with subwavelength scales and quasi-periodic properties. By carefully designing their geometry, material properties, and arrangement, they can flexibly manipulate the amplitude, phase, polarization, and propagation direction of electromagnetic waves, thereby achieving efficient control of electromagnetic waves. Therefore, metasurfaces, with their advantage in manipulating electromagnetic waves, have become an effective tool for realizing electromagnetic wave polarization control. To achieve flexible control of electromagnetic wave polarization, researchers both domestically and internationally have proposed numerous dynamic polarization control metasurface schemes in recent years, including mechanical control, liquid metal, and paper-cut metasurface technology. Electron-reconfigurable polarization conversion metasurfaces (PCMs) integrate adjustable lumped elements such as PIN diodes and varactor diodes within a unit structure, combined with a field-programmable gate array (FPGA) system, enabling real-time control of electromagnetic wave polarization. Compared to the aforementioned polarization control schemes, it offers significant advantages, including fast response speed, high integration, and flexible design. Therefore, PCMs have become an effective approach for flexible control of electromagnetic wave polarization. Currently, relying on electron-reconfigurable metasurface technology, multi-band and multi-functional polarization conversion can be achieved. For example, when the PIN diode within the metasurface is in the ON state, under linearly polarized wave incident conditions, it can be converted to a cross-polarized wave in the 7.30–8.90 GHz and 19.40–24.92 GHz bands, and to a circularly polarized wave in the 9.79–17.42 GHz band. When the diode is in the OFF state, cross-polarization conversion can be achieved in the 8.9–13.22 GHz band, and linear-to-circular polarization conversion can be achieved in the 7.60–8.30 GHz and 14.71–16.83 GHz bands. Furthermore, multiple polarization conversions can be achieved within the same frequency band. For instance, in a reflective four-polarization reconfigurable switching metasurface, efficient switching between horizontal linear polarization (HP), vertical linear polarization (VP), left-hand circular polarization (LHCP), and right-hand circular polarization (RHCP) can be achieved by adjusting the diode bias voltage.In a broadband multifunctional reconfigurable polarization conversion metasurface, by controlling the "on" and "off" states of the PIN diodes, linear polarization to cross-linear polarization conversion with a relative bandwidth of 88.4% (5.69GHz–15.34GHz) and linear polarization to circular polarization conversion with a relative bandwidth of 83.75% (6.05GHz–14.76GHz) can be achieved.

[0003] Although PMCs possess the ability to rapidly switch between different electromagnetic wave polarizations, they can only dynamically control the polarization of plane waves incident at a fixed angle. This limits their ability to meet the polarization matching requirements of electromagnetic wave signals from different incident angles, thus significantly restricting their signal reception range in communication systems. To address these challenges, reconfigurable metasurface antenna technology enables efficient modulation of electromagnetic wave signals with different directions and polarizations. Existing technology proposes a one-bit beam-scanning reflective array antenna with four polarization switching functions. By changing the operating state of the PIN diodes, dynamic switching between HP, VP, LHCP, and RHCP can be achieved within a beam scanning range of 0° to 40°. Drawing on the principle of polarization conversion, existing technology proposes a novel broadband high-efficiency beam-scanning transmitting array that converts x-polarized electromagnetic waves emitted from a horn feed into y-polarized electromagnetic waves and achieves beam scanning within a range of 0° to 50°. Subsequently, existing technology has proposed a bidirectional beam scanning aperture with switchable transmission-reflection modes, which can simultaneously achieve dynamic control of co-polarized reflective beams and cross-polarized transmission beams within a scanning angle range of 0° to 45°. Previous work clearly shows that although current reconfigurable metasurface antennas have made breakthrough progress in controlling the polarization of scanning beams, the polarization conversion function is controlled at the unit level. This approach leads to several common problems, including difficulty in extending the operating bandwidth, limited polarization control types, and poor polarization stability. These problems remain unresolved due to the lack of an effective control theory for fully polarized beams. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides an ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces. It proposes a novel fully polarized beam control theory based on array factor-controlled orthogonal polarization vector field superposition. Theoretical calculations and full-wave simulations of the proposed fully polarized beam control theory are performed, verifying its effectiveness and versatility in achieving ultrawideband fully polarized large-angle beam scanning using only one bit of phase resolution.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: an ultra-wideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces, comprising the following steps: S1, adjusting the far-field phase of the beam based on the array global reference phase, includes the following steps: S11. Based on array synthesis theory, the expression for the radiation pattern of a reflective array antenna is derived as the product of the element factor and the array factor. Traditional multi-polarization beam modulation based on the element level requires multi-bit phase resolution. A method for beam far-field 0°~360° phase modulation based on one-bit array phase coding of the global reference phase of the array is proposed. S12, calculate the phase compensation amount of each unit in the array that generates the fixed radiation beam according to the beam scanning phase compensation formula; S13, by changing the global reference phase, each unit in the array is phase-coded and arranged according to the one-bit phase quantization rule, so as to realize the phase control of the beam far field from 0° to 360° by one-bit array phase coding; S2, a technology for achieving full polarization beam control based on array factor modulation of orthogonal polarization vector field superposition; In S2, achieving full polarization beam control using array factor modulation includes the following steps: S21 uses the principle of electromagnetic field vector synthesis to decompose electromagnetic waves and sets the scanning angle and polarization mode of the beam. S22, based on the principle of electromagnetic field vector synthesis, decomposes any polarized electromagnetic wave into two orthogonal linearly polarized waves. By independently encoding the global reference phase of the x-polarized component and y-polarized component in the array, it achieves effective control of the fully polarized radiation beam. S23, based on the one-bit phase quantization rule, the compensation phase of the x-polarization component and the y-polarization component in the array is quantized into two states: "0" and "π". Assuming the polarization direction of the feed horn is at a 45° angle to the positive x-axis, the incident field will be decomposed into x-polarized and y-polarized electric field components with equal amplitude and phase. S24, by performing one-bit array phase encoding on the x-polarized and y-polarized component fields, two beams with the same scanning direction are generated, and the far-field phase difference between the two beams is controlled by the global reference phase difference between the two orthogonal linear polarizations in the array; S25, based on the global reference phase control radiation beam far-field phase theory of array, precisely controls the far-field phase difference between two beams by setting the global reference phase difference between two orthogonal linear polarizations in the array. By vector superposition of x-polarization and y-polarization components in the far-field region, efficient control of the fully polarized beam is achieved. S3, theoretical calculation verification and full-wave simulation verification of ultra-wideband fully polarized large-angle beam scanning.

[0006] Furthermore, in S11, by depicting a reflection array composed of M×N elements placed on the xoy plane, with the phase center of the feed horn located at (F,0,0), according to array theory, the far-field radiation pattern expression of the reflection array antenna is: ; in, q e It is the power factor of the unit radiation pattern. q f It is the power factor of the feedhorn radiation pattern. i f ( m , n () is the spherical angle in the feed coordinate system. and These are the feed horn and the ( ) in the reflector array. m , n The position vector of ) units, k It is the wavenumber in free space. It is the direction of the radiation beam, | R m,n | is the ( m , n The reflection amplitude of each unit, f m,n It is the ( ) m , n The compensation phase provided by each unit.

[0007] Furthermore, in S11, according to the product theorem of radiation patterns, the far-field radiation pattern of the array... E ( i , f ) is a unit factor EF ( i ) and array factor AF ( i , f The product of ) ; Calculate the phase compensation of each element in the array to realize the radiation beam along the specified direction; In S12, the formula for calculating the phase compensation of each element in the array is as follows: ; in, P 0 indicates the global reference phase of the array.

[0008] Furthermore, in S13, the one-bit phase quantization rule is described by the following expression: ; In this array, the compensation phase of each unit is quantized into a "0" state or a "π" state. Different values ​​of the global reference phase will affect the phase coding arrangement of each unit in the array. By theoretically calculating the far-field phase corresponding to the global reference phase from 0° to 360° in the array, there is a good linear mapping relationship between the global reference phase difference in the array and the far-field phase difference in different main lobe directions. Therefore, the control of the far-field phase of the beam from 0° to 360° can be achieved by using array phase coding with a resolution of one bit.

[0009] Furthermore, in S22, the phase distribution of the x-polarized and y-polarized electric fields in the array is represented as follows: ; in, and These are the global reference phases of the x-polarized electric field and the y-polarized electric field, respectively, and their relationship is as follows: ; in, d It is an uncertain value, depending on the polarization mode of the reflector antenna.

[0010] Furthermore, in S23, the expression for the one-bit phase quantization rule is: .

[0011] Furthermore, in S3, the theoretical calculation verification and full-wave simulation verification of fully polarized beam control include the following steps: S31 uses a particle swarm optimization algorithm to optimize the global reference phase in order to achieve optimal control of the scanning angle, polarization and gain of the radiation beam. Finally, the theoretical calculation verification of ultra-wideband fully polarized large-angle beam scanning based on array factor-controlled orthogonal polarization vector field superposition is completed. S32, through unit design and analysis, performs full-wave simulation verification of the fully polarized beam control theory; through theoretical calculation, the relationship between different global reference phase differences and beam far-field phase differences is obtained, and the effectiveness of the relationship under ultra-wideband and large-angle beam scanning conditions is verified through full-wave simulation.

[0012] Furthermore, in S31, the PSO optimization process for the generated beam's scanning angle, axial ratio, and radiation gain includes the following steps: S311 defines the solution space, the overall size, and the fitness function; S312, initialize the position and velocity of each particle; S313, update the position and velocity of each particle by generating a global reference phase. The phase compensation for x-polarization and y-polarization is generated, the scanning angle, axial ratio and radiation gain of the generated beam are calculated and the fitness function is evaluated, thereby updating the best position found so far for each particle and the best position found for all particles in the entire swarm. S314, determine if convergence has occurred; if so, obtain the final optimized result. If not, repeat steps S313 until the particle swarm converges.

[0013] Furthermore, in S32, the full-wave simulation verification of the fully polarized beam control theory is carried out through unit design and analysis. This includes designing a reconfigurable reflection unit with a one-bit phase resolution that can independently control x-polarization and y-polarization, and performing full-polarized array antenna simulation to verify the effectiveness and universality of the fully polarized beam control theory.

[0014] The above approach has the following beneficial effects: 1. This solution addresses the shortcomings of existing technologies, which can only adjust the polarization of plane waves and do not consider the phase delay between the feed and the array surface, making them difficult to apply to antenna polarization control. This paper proposes combining a dual-polarized one-bit reconfigurable metasurface with a single antenna. By adjusting the amplitude, phase, and polarization characteristics of the feed radiation beam, this overcomes the limitation that polarization-controlled metasurfaces cannot be applied to receiving antennas. This not only enables multiple functions within a single system, such as multi-polarization conversion and beam scanning, but also improves the integration and efficiency of the antenna system, potentially providing a solution for the efficient reception of fully polarized electromagnetic wave signals.

[0015] 2. This solution addresses the shortcomings of existing technologies, such as narrow polarization modulation bandwidth and poor polarization stability in large-angle beam scanning range. It proposes a method for controlling the far-field phase of the beam from 0° to 360° based on a global reference phase in the array. Verification shows that within a 10-octave ultra-wideband range, the global reference phase difference in the array exhibits a good linear mapping relationship with the far-field phase difference of the beam. Furthermore, this relationship is unaffected by the beam scanning angle and the array phase coding resolution. Therefore, by encoding the array phase with a single bit, the far-field phase of the beam can be controlled within the 0° to 360° range. Based on this principle, the phase compensation used to generate two orthogonal linearly polarized beams with the same pointing direction is first determined through theoretical calculations. Then, the global reference phase difference between the x-polarization and y-polarization components in the array is set according to the expected beam polarization mode. Finally, a single bit of phase modulation is applied to the phase compensation of the two orthogonal linearly polarized components in the array to control the far-field phase difference between the two orthogonal polarized beams, thereby achieving ultra-wideband full-polarization large-angle beam scanning. This method is of great value for the design and application of fully polarized array antennas.

[0016] 3. This scheme addresses the limitation of polarization mode control in existing technologies by proposing a fully polarized beam control theory based on array factor-controlled vector field superposition. It innovatively proposes an ultra-wideband control mechanism for the far-field radiation phase of the beam from 0° to 360° using a global reference phase of the array surface, by establishing a mapping relationship between beam and polarization control and phase coding. Combined with electronic reconfiguration technology, it achieves flexible control of arbitrary polarization modes of the far-field beam using only one bit of array phase coding, providing theoretical support for simplifying the architecture of fully polarized signal receiving metasurface antennas.

[0017] 4. This scheme first proposes a method to modulate the far-field phase of the beam by modulating the global reference phase in the array. Subsequently, it verifies that within a 10-octave ultra-wideband range, the global reference phase difference in the array and the far-field phase difference of the beam exhibit a good linear mapping relationship. Furthermore, this relationship is unaffected by the beam scanning angle and the array phase coding resolution. Therefore, a single-bit array phase coding is sufficient to achieve far-field phase modulation from 0° to 360°. Based on the above principle, we propose a theory for ultra-wideband fully polarized large-angle beam scanning based on array factor-controlled vector field superposition. First, the array phase coding used to generate two orthogonal linearly polarized beams with the same radiation direction is calculated and determined using the phase compensation formula. Then, the global reference phase difference between the x-polarized and y-polarized components in the array is set according to the expected beam polarization. Finally, a single-bit phase modulation is applied through phase compensation of the two orthogonal linearly polarized components in the array to control the far-field phase difference between the two orthogonal polarized beams, thereby achieving ultra-wideband fully polarized large-angle beam scanning. This method is of great value for the design and application of fully polarized array antennas.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the method steps in an embodiment of the ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to the present invention. Figure 2 This is a schematic diagram of the space-fed reflective array antenna architecture in S11 of an embodiment of an ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to the present invention. Figure 3 In S13 of an embodiment of the ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces of the present invention, P 0 = 0° and P A schematic diagram of the far-field theoretical calculation results under the condition of 0=90°; Figure 4In S13 of an embodiment of the ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces of the present invention, P 0 = 40° and P A schematic diagram of the far-field theoretical calculation results under the condition of 0=130°; Figure 5 The global reference phase difference in the array of an embodiment of an ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to the present invention. d Phase difference with far field Δ f A diagram illustrating the relationships between them; Figure 6 This is a schematic diagram showing the relationship between the global reference phase difference and the far-field phase difference of the beam in an array within a 10-octave bandwidth, according to an embodiment of an ultra-wideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces of the present invention. Figure 7 This is a schematic diagram of the phase configuration of the x-polarization, y-polarization, and overall phase distribution in the array required to realize the fully polarized beam in an embodiment of the ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to the present invention. Figure 8 This is a schematic diagram of the Poincaré sphere and the calculated polarization efficiency in an embodiment of an ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to the present invention. Figure 9 This is a schematic diagram showing the relationship between the far-field phase difference between the x-polarization and y-polarization components of the fully polarized beam and the corresponding global reference phase difference in the array, according to an embodiment of the ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces of the present invention. Figure 10 In an embodiment of the ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces of the present invention, when using one-bit phase array encoding, the global reference phase is optimized. A schematic diagram showing the results of modulating the phase difference in the far field of orthogonal polarization.

[0020] Figure 11 This is a schematic diagram of the unit structure of an embodiment of an ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to the present invention. Figure 12 This is a schematic diagram of the simulation results of the unit reflection coefficient under different PIN diode states and perpendicular incidence of y-polarization and x-polarization, according to an embodiment of the ultra-wideband fully polarized large-angle beam scanning method based on electromagnetic metasurface of the present invention. Figure 13 This is a schematic diagram of a fully polarized beam reconfigurable reflective array antenna, representing an embodiment of an ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to the present invention. Figure 14This is a schematic diagram of the full-wave simulation results of beam scanning in right-hand circular polarization (RHCP) mode, according to an embodiment of the ultra-wideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces of the present invention. Figure 15 This is a schematic diagram of the full-wave simulation results of beam scanning in left-hand circular polarization (LHCP) mode, according to an embodiment of the ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces of the present invention. Figure 16 This is a schematic diagram of the full-wave simulation results of beam scanning in horizontal linear polarization (HP) and vertical linear polarization (VP) modes in an embodiment of an ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to the present invention. Figure 17 This is a schematic diagram of the simulated gain curves of HP, LHCP, RHCP and VP beams radiating along the normal direction at 6 GHz, according to an embodiment of the ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] The following detailed description illustrates the specific implementation method: Example: As attached Figure 1-Figure 17 As shown: A method for ultrawideband fully polarized large-angle beam scanning based on electromagnetic metasurfaces includes the following steps: S1, adjusting the far-field phase of the beam based on the array global reference phase, includes the following steps: S11, such as Figure 2 Depicting the reflective array antenna and expressing its far-field radiation pattern according to array theory, by depicting an M×N element reflective array placed on the xoy plane, with the phase center of the feed horn located at (F,0,0), the far-field radiation pattern expression of the reflective array antenna is as follows: (1); in, q e It is the power factor of the unit radiation pattern. q f It is the power factor of the feedhorn pattern. i f ( m , n () is the spherical angle in the feed coordinate system. and These are the feed horn and the ( ) in the reflector array. m , n The position vector of ) units. k It is the wavenumber in free space. It is the direction of the radiation beam, | R m,n | is the ( m , n The reflection amplitude of each unit, f m,n It is the ( ) m , n The compensation phase provided by each unit.

[0025] S12, calculate the far-field radiation pattern of the array based on the radiation pattern, and calculate the phase compensation amount of each element in the array according to the phase compensation formula. According to the product theorem of radiation patterns, the far-field radiation pattern of the array is... E ( i , f ) is a unit factor EF ( i ) and array factor AF ( i , f The product of ) (2); Due to unit factor EF ( i and array factor AF ( i , fThese factors jointly influence the far-field radiation pattern and polarization mode. Research on traditional polarization-reconfigurable metasurface antennas is based on adjusting the element factor. EF ( i The principle behind polarization conversion is as follows: Different types of polarization beam conversion are achieved by phase modulation of the two orthogonal polarization components of the incident wave at the unit cell level. For example, converting a horizontally polarized (HP) beam to a vertically linearly polarized (VP) beam requires the metasurface unit cell to have one bit of orthogonal linear polarization phase modulation capability. To achieve polarization beam conversion from linearly polarized (LP) to circularly polarized (CP), the unit cell must provide two bits of phase resolution for the two orthogonal linearly polarized components, as shown in Table I. However, based on the unit factor... EF ( i The polarization control of ) faces three major problems, including: 1) the design of multi-bit phase resolution units is complex; 2) the types of polarization modulation are limited; and 3) the working bandwidth of polarization modulation is narrow and the angle stability of polarization is poor.

[0026] Table I: Polarization states corresponding to different phase delays of orthogonal polarization vectors

[0027] To address the aforementioned issues, a theory for achieving ultra-wideband fully polarized large-angle beam scanning based on array factor-controlled orthogonal polarization vector field stacking is proposed. First, the method for controlling the far-field phase of the beam based on the global reference phase in the array will be described in detail.

[0028] For space-fed reflector array antennas, in order to achieve a along- The radiation beam is directed in a specific direction. The phase compensation amount for each element in the array is calculated using the array phase compensation formula to achieve the radiation beam along the specified direction. The calculation formula for the phase compensation amount of each element in the array is as follows: (3); in, P 0 indicates the global reference phase of the array.

[0029] S13, by encoding and arranging each phase in the array using a one-bit phase quantization rule, a one-bit dual-polarization reconfigurable unit can independently control the phases of two orthogonal linear polarizations in the array to achieve full polarization beam control. The one-bit phase quantization rule is described by the following expression: (4); In this array, the compensation phase of each unit is quantized into either a "0" state or a "π" state, although the different values... P 0 does not change the direction of the radiated beam, but it does affect the phase coding arrangement of each element in the array. To investigate... P The effect of 0 on the far-field characteristics of the beam can be obtained from equation (1) by comparing the amplitude and phase of the main beam with those of the beam. P The relationship curve between 0 and 0. Assume the operating frequency of the reflector antenna is... f 0, the aperture size consists of 16×16 units, and the period of each unit is... l 0 / 2. The horn feed is placed vertically at the normal position of the array center. Its radiated power factor is... q f =3.5, focal diameter ratio F / D =1. Through theoretical calculations based on equations (3) and (4), the results were obtained respectively. P 0 = 0° and P In the two cases of 0° and 90°, the beam direction is ( i =10°, f Normalized far-field amplitude and far-field phase at (=0°), such as Figure 3 As shown, the results indicate that although the far-field amplitudes of the two beams are the same, different coding affects the sidelobes of the beams. Observations revealed an 86° phase shift in the far-field radiation phase along the radiation beam direction, which is basically consistent with the given global reference phase difference of the array.

[0030] like Figure 4 As shown, in P 0 = 40° and P Under the condition that θ = 130°, the direction of radiation is ( i =30°, f The normalized far-field amplitudes of the two beams (0°) are equal, and the far-field phase difference is 90°. These phenomena suggest that there may be a specific relationship between the far-field phase difference of the radiated beam and the global reference phase difference in the array.

[0031] Considering that different values ​​of the global reference phase affect the phase encoding arrangement of each element in the array, theoretical calculations were performed on the far-field phases corresponding to the global reference phases from 0° to 360° in the array. This revealed a good linear mapping relationship between the global reference phase difference in the array and the far-field phase differences in different main lobe directions. Figure 5 As shown in (a). Figure 5 (b) illustrates the global reference phase difference and pointing in the array under different coding phase resolutions. i =0°, f The relationship between the far-field phase difference of the main lobe (0°) and the phase difference of the main lobe is shown in the curve. The results indicate that this linear mapping relationship between the global reference phase difference in the array and the far-field phase difference pointed to by the main lobe is not affected by the phase coding resolution. Therefore, in order to simplify the design of the metasurface unit and reduce the structural complexity of the system, a one-bit array phase coding can be used to achieve the control of the beam far-field phase from 0° to 360°.

[0032] Based on the above analysis, a fully polarized beam control is achieved by independently controlling the phases of two orthogonally polarized elements in a one-bit dual-polarized reconfigurable element array. This method greatly simplifies the complex element structure design resulting from polarization control based on element factor modulation and provides theoretical support for realizing fully polarized beam control. Figure 6 This shows when the main lobe points to ( i =30°, f =0°) and ( i =45°, f The relationship between the global reference phase difference in the array and the far-field phase difference in the direction of the radiated beam (=30°) is shown. It can be seen that within a 10-octave bandwidth, when the beam points in different directions, the far-field phase difference of the main beam maintains a good linear mapping relationship with the global reference phase difference in the array. This indicates that using one bit of phase resolution in the array can achieve precise control of the far-field phase difference from 0° to 360° for radiated beams at different scanning angles over an ultra-wide operating frequency band.

[0033] S2, achieving fully polarized beam control based on array factor modulation of far-field orthogonal polarization vector field superposition includes the following steps: S21, using the principle of electromagnetic field vector synthesis to decompose electromagnetic waves, sets the scanning angle of the beam ( ) and polarization mode ( .

[0034] S22 utilizes the principle of electromagnetic field vector synthesis to decompose any polarized electromagnetic wave into two orthogonal linearly polarized waves. By independently encoding the global reference phases of the x-polarized and y-polarized components in the array, effective control of the fully polarized radiation beam is achieved. The phase distribution of the x-polarized and y-polarized electric fields in the array is shown below: (5); in, and These are the global reference phases of the x-polarized electric field and the y-polarized electric field, respectively, and their relationship is as follows: (6); in, d It is an uncertain value, depending on the polarization mode of the reflector antenna.

[0035] S23, based on the one-bit phase quantization rule, the compensation phase of the x-polarization component and the y-polarization component in the array is quantized into two states: "0" and "π". The expression for the one-bit phase quantization rule is as follows: (7); Assuming the polarization direction of the feed horn forms a 45° angle with the positive x-axis, the incident field can be decomposed into x-polarized and y-polarized electric field components with equal amplitude and phase. This achieves main lobe pointing (…). i =0°, f The array phase coding required for a fully polarized beam (=0°) is as follows: Figure 7 As shown. Accordingly, Table II presents... Figure 7 The fully polarized mode in the diagram describes the conditions satisfied by the global reference phases of the x-polarized and y-polarized arrays.

[0036] Table II: Global Reference Phase Difference and Array Phase Encoding in Fully Polarized Mode

[0037] To more intuitively explain the formation principle of the above-mentioned fully polarized state, Figure 8 (a) illustrates the representation of the fully polarized state on a Poincaré sphere. When representing electromagnetic wave polarization on a Poincaré sphere, the azimuth angle... ψ The angle is defined as the angle between the major axis of the polarization ellipse and the positive direction of the H-axis. The polarization ellipse is formed by the superposition of two linearly polarized field components. Ellipticity angle. x Defined as ,in a and b These are the major and minor semi-axes of the polarization ellipse, respectively. The Poincaré sphere can represent any polarization state of an electromagnetic wave. Each point on the sphere corresponds to a unique polarization state, characterized by its coordinate latitude 2. x and longitude 2 ψ Characterization, in which x Represents the ellipticity angle. ψ Indicates the azimuth angle.

[0038] In addition, the Poincaré sphere is used to calculate polarization efficiency ( or This provides an effective method. For example... Figure 8 As shown in (b), the desired polarization state of an electromagnetic wave is determined by a point on the sphere. w This indicates that the polarization of the reflector array antenna is determined by a point. c The angle between these two points is denoted as ∠. toilet The expression for polarization efficiency is shown in (8).

[0039] (8); Given the applicability of using the global reference phase in the array to adjust the far-field phase of the beam in ultra-wideband scenarios, we calculated the phase difference between the x-polarized and y-polarized far-field components of the fully polarized beam, as well as the corresponding global reference phase difference in the array, over a frequency range of 10 octaves. For example... Figure 9As shown, they clearly exhibit good consistency. Therefore, it can be concluded that the theory of fully polarized beam control based on array factor-controlled superposition of orthogonal polarization vector fields is also applicable to ultra-wideband operation.

[0040] S24 generates two beams with the same scanning direction by performing one-bit array phase encoding on the x-polarized and y-polarized component fields. The far-field phase difference between the two beams is controlled by the global reference phase difference between the two orthogonal linear polarizations in the array.

[0041] S25, based on the global reference phase control radiation beam far-field phase theory, precisely controls the far-field phase difference between two beams by setting the global reference phase difference between two orthogonal linear polarizations in the array. In the far-field region, the x-polarized and y-polarized component fields are vector-superimposed, thereby achieving efficient control of the fully polarized beam.

[0042] S3. The theoretical calculation verification and full-wave simulation verification of fully polarized beam control include the following steps: S31, taking the polarization control of the reflected beam as an example, assuming the number of array elements is 32×32, the power factor of the fed horn... q f =1.675. The feed polarization direction forms a 45° angle with the positive x-axis. The global reference phase is adjusted using a particle swarm optimization algorithm. Optimization is performed to achieve optimal control over the scanning angle, polarization, and gain of the radiated beam. The PSO optimization process for the generated beam's scanning angle, axial ratio, and radiation gain includes the following steps:

[0043] S311 defines the solution space, the overall size, and the fitness function.

[0044] S312 initializes the position and velocity of each particle.

[0045] S313, update the position and velocity of each particle by generating a global reference phase. The phase compensation for x-polarization and y-polarization is generated, the scanning angle, axial ratio and radiation gain of the generated beam are calculated and the fitness function is evaluated, thereby updating the best position found so far for each particle and the best position found for all particles in the entire swarm.

[0046] S314, determine if convergence has occurred; if so, obtain the final optimized result. If not, repeat steps S313 until the particle swarm converges.

[0047] Figure 10 This demonstrates the generation of radiation directions using a one-bit array phase encoding. i = 0°, fOptimize global reference phase when using a fully polarized beam (= 0°) The results of modulating the far-field phase difference of orthogonal polarization before and after. It can be seen that optimizing the global reference phase... The global reference phase difference of orthogonal polarization in the array and the far-field phase difference of the corresponding beam satisfy a proportional function relationship. Therefore, one-bit array phase coding can be used to achieve precise control of the fully polarized beam.

[0048] The theoretical calculation verification of the principle of full polarization beam control based on array factor modulation of orthogonal polarization vector field superposition is shown in Table III.

[0049] Table III: Theoretical calculation results of six polarization beam modulations in different scanning directions ; Table III presents the theoretical calculation results of the normalized far-field amplitude and far-field phase of the two orthogonally polarized beams, as well as the three-dimensional radiation patterns and polarization efficiencies of six target polarized beams at different beam scanning angles. Theoretical calculation results show that the method of superimposing two orthogonal polarization vector fields based on array factor modulation can achieve precise control of the fully polarized beam, with high accuracy in both beam pointing and polarization efficiency.

[0050] S32, through unit design and analysis, performs full-wave simulation verification of the fully polarized beam control theory, including: designing a reconfigurable reflection unit with one-bit phase resolution capable of independently controlling x-polarization and y-polarization, such as... Figure 11 As shown. Two orthogonally polarized dipoles are mounted on F4B (dielectric constant) substrate with a thickness of 1 mm. Loss tangent On the substrate. The geometric parameters of the dual-polarized reconfigurable reflective unit are given in Table IV.

[0051] Table IV: Parameters of Reconfigurable Reflection Units

[0052] The simulation results of this unit are as follows: Figure 12 As shown. From Figure 12 As can be seen from (a) and (b), when the element is subjected to perpendicular incidence of a y-polarized wave, the reflection amplitudes of the four states "01", "00", "11", and "10" are all greater than -1 dB. Specifically, within the frequency range of 3.49 GHz to 8.94 GHz, the states "01" and "00", and the states "11" and "10", exhibit a stable co-polarized reflection phase difference within a range of 180° ± 37°. Similarly, in... Figure 12As can be observed in (c) and (d), when the unit operates in the x-polarization state, the reflection amplitude of the four states "10", "00", "11" and "01" is greater than -1dB, and the phase difference of the same polarization reflection of the two states "10" and "00" and the two states "11" and "01" fluctuates within the range of 180°±37° in the frequency range of 3GHz to 9GHz.

[0053] The relationship between different global reference phase differences and far-field phase differences was obtained through theoretical calculations, and the effectiveness of the proposed method of achieving full polarization beam control based on array factor-controlled orthogonal polarization vector field superposition in ultra-wideband and large-angle beam scanning was verified by full-wave simulation of the fully polarized array antenna. Figure 13 The antenna on display is a reconfigurable reflective array antenna consisting of 22×22 elements (PIN diodes). The polarization direction of the double-ridged horn antenna is placed at a 45° angle to the positive x-axis as the feed antenna, and its phase center is located in the normal direction of the metasurface.

[0054] Full-wave simulations of beam scanning of a reconfigurable reflective array antenna under different polarizations in the ultra-wideband were performed using the full-wave simulation software CST Microwave Studio®. Figure 14 It can be seen that the right-hand circularly polarized (RHCP) beam operating at 3.5 GHz... f The far-field radiation pattern from 0° to 60° in the 90° plane matches the expected direction well, and the axial ratio in the radiation direction is completely less than -3dB. From Figure 15 It can be seen that the left-hand circularly polarized (LHCP) beam operating at 6 GHz... f The beam scanning results from 0° to 60° in the 0° plane are consistent with the theoretical calculations, and the axial ratios are all below -3dB. Figure 16 As shown, the horizontally polarized (HP) beam operating at 8 GHz and the vertically polarized (VP) beam operating at 8.5 GHz are respectively... f =45° and f The far-field radiation patterns of the scanned beams from 0° to 60° within the 135° plane are consistent with the theoretical results. Furthermore, the simulated gain and aperture efficiency of the aforementioned beams with different polarizations at the corresponding frequencies are listed in Table V. These simulation results collectively verify the effectiveness of the proposed theory of full-polarization beam control based on column factor-controlled orthogonal polarization vector field superposition for ultra-wideband large-angle beam scanning.

[0055] The simulated gain curve of the reflective array antenna radiating beam along the normal direction is as follows: Figure 17As shown, at 6 GHz, the gains for horizontal polarization (HP), left-hand circular circular polarization (LHCP), right-hand circular circular polarization (RHCP), and vertical polarization (VP) are 20.67 dBi, 20.04 dBic, 20.17 dBic, and 19.97 dBi, respectively. Their 3 dB gain bandwidths are 39.7%, 36.4%, 46.2%, and 43.6%, respectively.

[0056] Table V: Simulation results for beam scanning, polarization type, gain, and aperture efficiency. ; In this invention, we propose a fully polarized beam control theory based on array factor modulation of orthogonal polarization vector field superposition. First, by performing one-bit phase encoding on the two orthogonal linear polarization component fields in the array, two beams with the same radiation direction are generated. The far-field phase difference between these two orthogonal polarized beams is precisely modulated using the global reference phase difference of the two orthogonal linear polarizations in the array, thereby achieving fully polarized beam control in the main lobe direction. Theoretical calculations and full-wave simulations verify that this technique can achieve ultra-wideband and large-angle domain fully polarized beam scanning using only one bit of phase resolution. It is no longer limited to complex unit structures capable of independently controlling multi-bit orthogonal linear polarization phases, greatly simplifying unit structure design, reducing the complexity and production cost of array antenna systems, and providing important theoretical support for the research of fully polarized array antennas.

[0057] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for ultrawideband fully polarized large-angle beam scanning based on electromagnetic metasurfaces, characterized in that, Includes the following steps: S1, adjusting the far-field phase of the beam based on the array global reference phase, includes the following steps: S11. Based on array synthesis theory, the expression for the radiation pattern of a reflective array antenna is derived as the product of the element factor and the array factor. Traditional multi-polarization beam modulation based on the element level requires multi-bit phase resolution. A method for beam far-field 0°~360° phase modulation based on one-bit array phase coding of the global reference phase of the array is proposed. S12, calculate the phase compensation amount of each unit in the array that generates the fixed radiation beam according to the beam scanning phase compensation formula; S13, by changing the global reference phase, each unit in the array is phase-coded and arranged according to the one-bit phase quantization rule, so as to realize the phase control of the beam far field from 0° to 360° by one-bit array phase coding; S2, a technology for achieving full polarization beam control based on array factor modulation of far-field orthogonal polarization vector field superposition; In S2, the full polarization beam control based on the array factor modulation of the far-field orthogonal polarization vector field superposition includes the following steps: S21, using the principle of electromagnetic field vector synthesis to decompose electromagnetic waves, sets the scanning angle of the beam ( ) and polarization mode ( ; S22, based on the principle of electromagnetic field vector synthesis, decomposes any polarized electromagnetic wave into two orthogonal linearly polarized waves. By independently encoding the global reference phase of the x-polarized component and y-polarized component in the array, the effective control of the fully polarized radiation beam is achieved. S23, based on the one-bit phase quantization rule, the compensation phase of the x-polarization component and the y-polarization component in the array is quantized into two states: "0" and "π". Assuming the polarization direction of the feed horn is at a 45° angle to the positive x-axis, the incident field will be decomposed into x-polarized and y-polarized electric field components with equal amplitude and phase. S24, by performing one-bit array phase encoding on the x-polarized and y-polarized component fields, two beams with the same scanning direction are generated, and the far-field phase difference between the two beams is controlled by the global reference phase difference between the two orthogonal linear polarizations in the array; S25, based on the global reference phase control radiation beam far-field phase theory of array, precisely controls the far-field phase difference between two beams by setting the global reference phase difference between two orthogonal linear polarizations in the array. By vector superposition of x-polarization and y-polarization components in the far-field region, efficient control of the fully polarized beam is achieved. S3, theoretical calculation verification and full-wave simulation verification of ultra-wideband fully polarized large-angle beam scanning.

2. The ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to claim 1, characterized in that, In S11, by depicting a reflection array composed of M×N elements placed on the xoy plane, with the phase center of the feed horn located at (F,0,0), according to array theory, the far-field radiation pattern expression of the reflection array antenna is: ； in, q e It is the power factor of the unit radiation pattern. q f It is the power factor of the feedhorn radiation pattern. θ f ( m , n () is the spherical angle in the feed coordinate system. and These are the feed horn and the ( ) in the reflector array. m , n The position vector of ) units, k It is the wavenumber in free space. It is the direction of the radiation beam, | R m,n | is the ( m , n The reflection amplitude of each unit, φ m,n It is the ( ) m , n The compensation phase provided by each unit.

3. The ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to claim 2, characterized in that, In S11, according to the product theorem of radiation patterns, the far-field radiation pattern of the array is... E ( θ , φ ) is a unit factor EF ( θ ) and array factor AF ( θ , φ The product of ) ; Calculate the phase compensation of each element in the array to realize the radiation beam along the specified direction; In S12, the formula for calculating the phase compensation of each element in the array is as follows: ; in, Ψ 0 indicates the global reference phase of the array.

4. The ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to claim 3, characterized in that, In S13, the one-bit phase quantization rule is described by the following expression: ； In this array, the compensation phase of each unit is quantized into a "0" state or a "π" state. Different values ​​of the global reference phase will affect the phase coding arrangement of each unit in the array. By theoretically calculating the far-field phase corresponding to the global reference phase from 0° to 360° in the array, there is a good linear mapping relationship between the global reference phase difference in the array and the far-field phase difference in different main lobe directions. Therefore, the control of the far-field phase of the beam from 0° to 360° can be achieved by using array phase coding with a resolution of one bit.

5. The ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to claim 4, characterized in that, In S22, the phase distribution of the x-polarized and y-polarized electric fields in the array is shown below: ； in, and These are the global reference phases of the x-polarized electric field and the y-polarized electric field, respectively, and their relationship is as follows: ； in, δ It is an uncertain value, depending on the polarization mode of the reflector antenna.

6. The ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to claim 5, characterized in that, In S23, the expression for the one-bit phase quantization rule is: 。 7. The ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to claim 6, characterized in that, In S3, the theoretical calculation verification and full-wave simulation verification of fully polarized beam control include the following steps: S31 uses a particle swarm optimization algorithm to optimize the global reference phase in order to achieve optimal control of the scanning angle, polarization and gain of the radiation beam. Finally, the theoretical calculation verification of ultra-wideband fully polarized large-angle beam scanning based on array factor-controlled orthogonal polarization vector field superposition is completed. S32, through unit design and analysis, performs full-wave simulation verification of the fully polarized beam control theory; through theoretical calculation, the relationship between different global reference phase differences and beam far-field phase differences is obtained, and the effectiveness of the relationship under ultra-wideband and large-angle beam scanning conditions is verified through full-wave simulation.

8. The ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to claim 7, characterized in that, In S31, the PSO optimization process for the generated beam's scanning angle, axial ratio, and radiation gain includes the following steps: S311 defines the solution space, the overall size, and the fitness function; S312, initialize the position and velocity of each particle; S313, update the position and velocity of each particle by generating a global reference phase. The phase compensation for x-polarization and y-polarization is generated, the scanning angle, axial ratio and radiation gain of the generated beam are calculated and the fitness function is evaluated, thereby updating the best position found so far for each particle and the best position found for all particles in the entire swarm. S314, determine if convergence has occurred; if so, obtain the final optimized result. If not, repeat steps S313 until the particle swarm converges.

9. The ultrawideband fully polarized large-angle beam scanning method based on electromagnetic metasurfaces according to claim 8, characterized in that, In S32, the full-wave simulation verification of the fully polarized beam control theory is carried out through unit design and analysis. This includes designing a reconfigurable reflection unit with one-bit phase resolution that can independently control x-polarization and y-polarization, and performing array full-wave simulation to verify the effectiveness and universality of the ultra-wideband fully polarized large-angle beam scanning theory.

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