Transparent dual-frequency reflective array antenna and phase compensation method thereof

Abstract

The application discloses a transparent dual-frequency reflective array antenna and a phase compensation method thereof, and belongs to the technical field of wireless communication.The antenna comprises a transparent medium, dual-frequency reflective array antenna units arranged on the transparent medium in an array, and a floor made of a transparent metal wire screen resistance film and laid on the bottom surface of the transparent medium.The dual-frequency reflective array antenna units are arranged in an interlaced manner by low-frequency and high-frequency reflective array antenna units, the low-frequency units are located in the center, adopt a first cross-dipole structure formed by fine metal wires, and can be extended into a Jerusalem cross structure; the high-frequency units are distributed around the low-frequency units, are composed of an outer ring, an inner ring and a second cross-dipole, and the phase is adjusted by changing the size of the inner ring and the second cross-dipole; and low-frequency and high-frequency feed sources are arranged above the array surface.The application realizes the transparentization of the dual-frequency reflective array, widens the phase compensation range by using a two-degree-of-freedom design, has the communication performance, optical transparency and multi-frequency band compatibility, and meets the multi-frequency band and transparent communication requirements of a smart city.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology, specifically relating to a transparent dual-frequency reflective array antenna and its phase compensation method. Background Technology

[0002] Against the backdrop of the accelerated development of smart cities, urban communication networks are rapidly upgrading towards full coverage, concealed integration, and green collaboration. Transparent antennas, as a new type of antenna that combines excellent communication functions with good environmental adaptability, have significant research value and broad application prospects.

[0003] Currently, some research in the industry has achieved transparency in planar reflective arrays, laying a foundation for the practical application of transparent antennas. For example, Chinese patent application CN117117519A proposes "a broadband optically transparent reflective array antenna based on hybrid dielectric and heterogeneous units." The patterned optically transparent conductive unit array and optically transparent conductive ground plane of this antenna are made of conductive materials with certain optical transparency properties. At least one of indium tin oxide, fluorine-doped tin oxide, conductive silver film, silver-plated polyester film, or silver nanowires can be selected to achieve optical transparency of the reflective array antenna. However, as communication systems rapidly evolve towards multi-band, multi-functional, and miniaturized designs, various smart terminals, IoT devices, and satellite communication payloads place increasingly higher demands on the frequency band compatibility, integration adaptability, and environmental adaptability of antennas. The transparent reflective array antennas in the aforementioned prior art can only achieve single-band communication functions, with limited frequency band coverage, making it difficult to meet the actual needs of multi-protocol communication collaboration and adapting to the application scenarios of multi-band communication systems.

[0004] To address the limitations of single-band antennas, adopting multi-antenna array integration solutions can easily lead to a series of new problems. On the one hand, the integration of multiple antenna arrays results in redundant equipment size and complex structure, making it difficult to meet the development trend of lightweight and miniaturized communication terminals. On the other hand, multiple antennas are prone to severe electromagnetic interference, affecting the stability of antenna communication performance and causing increased equipment energy consumption, which is inconsistent with the concept of green and collaborative development and has become a key bottleneck restricting the lightweight and high-performance development of communication terminals.

[0005] Furthermore, existing dual-band reflective array antennas cannot be applied to scenarios requiring optical transparency, making them unsuitable for the specific application needs of smart city construction, such as building integration and outdoor transparent carriers. For example, patent application CN116111359A proposes "a dual-band low radar cross-section reflective array antenna based on a three-dimensional frequency selection structure." This antenna uses a large amount of non-transparent dielectric material in its structural design, resulting in extremely low light transmittance. This fails to meet the optical transparency requirements of building curtain walls and transparent display devices, limiting its application in transparent scenarios. Summary of the Invention

[0006] The purpose of this invention is to address the problems in the prior art by providing a transparent dual-frequency reflective array antenna and its phase compensation method, thereby achieving transparency of the dual-frequency reflective array, expanding the phase compensation range by utilizing a two-degree-of-freedom design, and combining communication performance with optical transparency and multi-frequency band compatibility, thus meeting the multi-frequency and transparent communication needs in smart city construction.

[0007] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, a transparent dual-band reflective array antenna is provided, including a transparent medium and dual-band reflective array antenna elements arranged and laid on the transparent medium, wherein a floor made of a transparent metal mesh resistive film is laid on the bottom surface of the transparent medium. The dual-band reflective array antenna unit includes a low-frequency reflective array antenna unit and a high-frequency reflective array antenna unit, which are arranged alternately to form an array. The low-frequency reflective array antenna unit is located at the center of each dual-band reflective array antenna unit, while the high-frequency reflective array antenna units are distributed around the low-frequency reflective array antenna unit. The low-frequency reflective array antenna unit employs a first cross dipole structure made of fine metal wire, which can extend to form a Jerusalem cross structure. The high-frequency reflective array antenna unit includes an outer square ring, an inner square ring, and a second cross dipole structure, all made of fine metal wire from the outside in. Phase modulation is achieved by changing the dimensions of the inner square ring and the second cross dipole structure. The dual-band reflective array antenna elements are equipped with low-frequency and high-frequency feed sources above them.

[0008] As a preferred embodiment, the width of the fine metal wire is <50μm.

[0009] As a preferred embodiment, the size of the outer ring is fixed, while the width of the inner ring varies during phase adjustment. w2 The length of the second cross dipole structure is changed. w3 follow w2 change.

[0010] As a preferred embodiment, the sheet resistance of the transparent metal mesh resistive film is 0.06Ω.

[0011] As a preferred embodiment, the transparent medium is quartz glass with a relative permittivity of 3.75, a loss tangent of 0.0004, and a thickness h = 1 mm.

[0012] As a preferred embodiment, the length of the first cross dipole structure l1 When the change reaches the period size of the dual-band reflective array antenna element, the end of the fine metal wire is rotated 90° and then extended symmetrically to both sides, with the length of the extended portion being... l2 This forms the Jerusalem cross structure.

[0013] As a preferred embodiment, both the low-frequency feed and the high-frequency feed adopt a standard gain horn antenna of 15dBi.

[0014] As a preferred option, the high-frequency feed is placed directly above the dual-band reflective array antenna elements arranged in the array, while the low-frequency feed is placed by rotating it 15° along the -x axis.

[0015] As a preferred option, the high-frequency beam pointing of the high-frequency feed is designed to be (90°, 30°), and the low-frequency beam pointing of the low-frequency feed is designed to be (0°, 30°).

[0016] Secondly, a phase compensation method for a transparent dual-band reflective array antenna is provided, wherein the dual-band reflective array antenna element is initially a Type 1 structure, and the length of the first cross dipole structure of the low-frequency reflective array antenna element is... l1 The period of the high-frequency reflective array antenna element is smaller than that of the dual-band reflective array antenna element, and the width of the inner square ring of the high-frequency reflective array antenna element is changed. w2 and the length of the second cross dipole structure w3 Phase compensation is performed; when the length of the first cross dipole structure of the low-frequency band reflective array antenna element is... l1 When the change reaches the period size of the dual-band reflective array antenna element, the dual-band reflective array antenna element becomes a Type 2 structure. After rotating the fine metal wire end of the first cross dipole structure by 90°, it extends symmetrically to both sides to form a Jerusalem cross structure for phase compensation. Phase required for specifying beam direction Calculate according to the following formula:

[0017] In the formula, The straight-line distance between the dual-band reflective array antenna elements and the feed source at different locations; Let the wave number be in free space. As a reference phase, This represents the position coordinates of a dual-band reflective array antenna element in Cartesian coordinates. Indicates the azimuth angle of the beam direction. This indicates the elevation angle of the beam direction.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: This invention presents a transparent dual-band reflective array antenna. By arranging low-frequency and high-frequency reflective array antenna elements in an alternating, coplanar array, and employing a fine metal wire forming process combined with a transparent dielectric substrate and a transparent metal mesh resistive film ground plane, it achieves a fully optically transparent design for the dual-band reflective array antenna. This overcomes the shortcomings of traditional transparent reflective array antennas, which only support single-band operation and have poor frequency band adaptability, as well as the low light transmittance and inability to adapt to transparent scenarios resulting from the use of non-transparent dielectrics in conventional dual-band reflective array antennas. It balances dual-band operation capability with high light transmittance. The centrally arranged, alternating, coplanar integrated layout of the high and low frequency antenna elements eliminates the need for two separate antenna arrays of different frequency bands, avoiding the bulky size and structural redundancy problems caused by multiple antenna stacking. This effectively reduces electromagnetic interference risks and lowers overall power consumption, meeting the design and development needs of modern communication terminals and electronic devices for lightweighting, integration, and unification. The low-frequency reflective array antenna unit of this invention adopts a first cross dipole structure, which can be expanded into a Jerusalem cross structure, enriching the dimensions of low-frequency impedance and radiation adjustment. The high-frequency reflective array antenna unit integrates an outer square ring, an inner square ring, and a second cross dipole composite structure. Precise phase adjustment is achieved by adjusting the dimensions of the inner square ring and the second cross dipole structure. This invention relies on a dual-structure degree of freedom design, which significantly widens the array phase compensation range and effectively improves the beam control capability and radiation performance under dual-band conditions. The antenna of this invention adopts a transparent dielectric combined with a fine metal wire radiation structure. The bottom is equipped with a commercially available transparent metal mesh resistive film as a ground reflective floor. It has excellent light transmission performance and good structural fit, and can be widely adapted to observation windows of vehicles, ships, and aircraft, as well as building glass curtain walls, transparent display devices, solar panels, and other light transmission scenarios. While ensuring visual transparency and lighting requirements, it simultaneously realizes multi-functional applications such as dual-band communication and radar detection. The antenna of this invention combines optical transparency, dual-band compatibility, and stable electromagnetic radiation performance, which can meet the construction requirements of smart city full coverage and covert communication, solve the practical problems of multi-protocol and multi-band collaborative communication, provide a reliable technical solution for transparent integrated communication equipment, and has significant engineering application value and promotion potential. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 Schematic diagram of the transparent dual-frequency reflective array antenna structure according to an embodiment of the present invention; Figure 2(a) is a top view of the high-frequency reflective array antenna element according to an embodiment of the present invention; Figure 2(b) is a side view of the high-frequency reflective array antenna element according to an embodiment of the present invention. Figure 3(a) Simulation results of electric field distribution of high-frequency reflective array antenna element with outer square ring according to embodiment of the present invention; Figure 3(b) Simulation results of electric field distribution of high-frequency reflective array antenna element without outer square ring in embodiment of the present invention; Figure 4 The reflection phase and co-polarization reflection coefficient curves of the high-frequency reflective array antenna element in this embodiment of the invention when the inner square ring and the second crossed dipole structure change; Figure 5(a) Top view of the dual-band reflective array antenna element of the present invention as a Type 1 structure; Figure 5(b) is a side view of the dual-band reflective array antenna element of the present invention as a Type 1 structure; Figure 5(c) Top view of the dual-band reflective array antenna element of the present invention as a Type 2 structure; Figure 5(d) is a side view of the dual-band reflective array antenna element of the present invention as a Type 2 structure; Figure 6 The length of the first cross dipole structure of the low-frequency band reflective array antenna element in this embodiment of the invention. l1 Phase shift curve and co-polarization reflection coefficient diagram during change; Figure 7 The length of the first cross dipole structure extension of the low-frequency band reflective array antenna element in this embodiment of the invention. l2 Phase shift curve and co-polarization reflection coefficient diagram during change; Figure 8(a) Length of the first cross dipole structure generated in MATLAB when the dual-band reflector array antenna element is of Type 1 structure according to the embodiment of the present invention. l1 Distribution diagram of variable frontal elements; Figure 8(b) shows the length of the first cross dipole structure extension when the dual-band reflector array antenna element is a Type 2 structure generated in MATLAB according to an embodiment of the present invention. l2 Distribution diagram of variable frontal elements; Figure 8(c) Distribution diagram of high-frequency reflective array antenna array elements generated in MATLAB according to an embodiment of the present invention; Figure 9 Simulation distribution diagram of antenna array elements after automatic modeling in this embodiment of the invention; Figure 10(a) E-plane radiation pattern of the transparent dual-frequency reflective array antenna of the present invention at 13.2 GHz; Figure 10(b) H-plane radiation pattern of the transparent dual-frequency reflective array antenna of the present invention at 13.2 GHz; Figure 11(a) E-plane radiation pattern of the transparent dual-frequency reflective array antenna of the present invention at 26.5 GHz; Figure 11(b) H-plane radiation pattern of the transparent dual-frequency reflective array antenna of the present invention at 26.5 GHz; Figure 12 The E-plane radiation pattern of the transparent dual-frequency reflective array antenna in the 11.2 GHz-15.2 GHz range according to an embodiment of the present invention; Figure 13 The H-plane radiation pattern of the transparent dual-frequency reflective array antenna in the 25GHz-28GHz range according to an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, those skilled in the art can obtain other embodiments without creative effort.

[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 be constructed and operated in a specific orientation. 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 current technologies, either transparent reflective array antennas can only achieve single-band communication, failing to meet the requirements of multi-band collaborative operation; or dual-band reflective array antennas lack optical transparency, making them unsuitable for transparent application scenarios. Both have significant technical shortcomings. Therefore, developing a reflective array antenna that combines optical transparency with dual-band communication capabilities, achieving transparency for dual-band reflective arrays, and meeting the multi-band, transparent communication needs in smart city construction, has important practical significance and value.

[0024] Please see Figure 1 This invention relates to a transparent dual-band reflective array antenna, comprising a transparent medium and dual-band reflective array antenna elements arranged and laid on the transparent medium. The bottom surface of the transparent medium is covered with a floor made of a transparent metal mesh resistive film. The transparent metal mesh resistive film used in this embodiment can be directly obtained by purchasing commercially available products. Its main structure consists of a periodic grid (i.e., a mesh) composed of micron-sized metal wires (copper or silver), which is embedded or coated on a transparent PET or glass substrate. The grid gaps allow for light transmission, while the metal wires provide conductivity and form a resistive floor. In this embodiment, the transparent metal mesh resistive film serves as both a transparent floor (reflective array grounding and reflective surface). Furthermore, the sheet resistance (SR) can be adjusted by precisely controlling the grid line width, grid spacing, and metal wire thickness, thereby meeting the antenna's impedance matching and reflection efficiency requirements. Unlike ordinary ITO films, which suffer from high brittleness and poor low-frequency reflection performance, the metal mesh transparent resistive film is specifically designed to meet the combined requirements of transparency, low loss, and grounding functionality of dual-band reflective arrays.

[0025] The dual-band reflective array antenna unit includes a low-frequency reflective array antenna unit 1 and a high-frequency reflective array antenna unit 2, which are arranged alternately to form an array.

[0026] The low-frequency reflective array antenna element 1 is located at the center of each dual-frequency reflective array antenna element, while the high-frequency reflective array antenna elements 2 are distributed around the low-frequency reflective array antenna element 1. The low-frequency reflective array antenna element 1 adopts a first cross dipole structure made of fine metal wire, which can be extended to form a Jerusalem cross structure. The high-frequency reflective array antenna element 2 includes an outer square ring, an inner square ring, and a second cross dipole structure, all made of fine metal wire from the outside to the inside. Phase modulation is achieved by changing the size of the inner square ring and the second cross dipole structure. A low-frequency feed 3 and a high-frequency feed 4 are arranged above the dual-band reflective array antenna elements in the array.

[0027] The antenna designed in this embodiment is a transparent antenna, which has high requirements for the light transmittance of the antenna. However, as the number of antenna layers increases, the light transmittance of the antenna will decrease rapidly. Therefore, this embodiment selects a single-layer structure design unit.

[0028] On the other hand, both the low-frequency reflective array antenna element 1 and the high-frequency reflective array antenna element 2 are designed and manufactured from fine metal wires. The width of the fine metal wires is <50μm, which is difficult to observe and perceive with the naked eye and is close to being transparent. Therefore, it is simple and effective to use fine metal wires to make the low-frequency reflective array antenna element 1 and the high-frequency reflective array antenna element 2 that meet the transparency requirements.

[0029] In this embodiment, the high-frequency reflective array antenna element 2 has a fixed outer square ring, which can suppress mutual coupling between elements. The reflection phase is adjusted by changing the size of the internal structure of the outer square ring. Simultaneously, the high-frequency reflective array antenna element 2 serves as a coupling patch for the low-frequency reflective array antenna element 1, achieving structural reuse. The low-frequency reflective array antenna element 1 adjusts its phase by varying the length of a fine metal wire. When the length of the first cross dipole structure... l1 When the change reaches the period size of the dual-band reflective array antenna element, the end of the fine metal wire is rotated 90° and then extended symmetrically to both sides, with the length of the extended portion being... l2 This forms the Jerusalem Cross structure, and the two-degree-of-freedom design expands the phase compensation range.

[0030] In this embodiment, the center frequencies of the transparent dual-frequency reflective array antenna are 13.2 GHz and 26.5 GHz, respectively. In order to improve the transmittance of the antenna, the high and low frequency reflective array antenna elements are designed with an alternating arrangement in the same layer.

[0031] Please refer to Figures 2(a) and 2(b). In this embodiment of the invention, the high-frequency reflective array antenna element 2 is located on the upper layer of the transparent medium and is composed of fine metal wires with a width of... g =40μm, period size of dual-band reflective array antenna element P =4 mm, from the outside to the inside: fixed outer square ring, width w1 =2.8mm; the inner square ring with varying width, i.e., during phase adjustment. w2 The width can vary. The diagram shows an example of a fixed width during the phase modulation process. At this time, w2 =1.84mm; and, the second cross dipole structure with varying length, i.e., during phase modulation. w3 The length can vary, and the length conforms to... w3 = w2 -0.6mm.

[0032] The transparent medium below is quartz glass with a relative permittivity of 3.75, a loss tangent of 0.0004, and a thickness of [missing information]. h =1mm. The lower layer of the transparent dielectric is a transparent resistive film with a sheet resistance of 0.06Ω, serving as the ground plane for the unit. In the final array antenna, units with different structures (i.e., different...) w2Each unit corresponds to a different reflection phase, thereby achieving phase compensation.

[0033] Since beam control of reflective array antennas relies on precise phase compensation, changes in other nearby elements can cause a deviation between the actual phase of the element and the simulated phase under periodic arrangement due to mutual coupling. Stronger mutual coupling amplifies this deviation, thus reducing element mutual coupling is necessary. To verify the suppression of element mutual coupling by the fixed outer ring of a high-frequency reflective array antenna element, the electric field distribution of the elements under periodic arrangement was simulated in CST (full-wave electromagnetic simulation software), as shown in Figures 3(a) and 3(b). It can be seen that the electric field of the high-frequency reflective array antenna element with the outer ring is significantly confined between the outer ring and the internal structure, while the electric field of the high-frequency reflective array antenna element without the outer ring diffuses significantly. This indicates that the mutual coupling between elements in the high-frequency reflective array antenna element with the outer ring is significantly improved, which is beneficial for subsequent antenna design.

[0034] To verify the phase shift characteristics of the high-frequency reflective array antenna element, this embodiment simulates the reflection phase and co-polarization reflection coefficient of the element at 26.5 GHz when the internal square ring and crossed dipole change. The specific curves are shown below. Figure 4 As shown. It can be seen that, with... w2 The phase compensation of the element can cover 360°, and the common polarization reflection coefficient of the element remains above -1.5dB during the phase change process, which provides good support for subsequent antenna design.

[0035] Please refer to Figures 5(a) to 5(d). In this embodiment of the invention, the low-frequency reflective array antenna element 1 is also located on the upper layer of the transparent medium, and a first cross dipole structure is constructed using fine metal wires, with a width... g =40μm, period size of dual-band reflective array antenna element P =8mm, the transparent dual-frequency reflective array antenna is designed as a two-degree-of-freedom element. The initial structure of the element is a Type 1 structure. When the length of the first cross dipole structure of the low-frequency reflective array antenna element 1 is... l1 When the value is changed to 7.5, the end of the fine metal wire is rotated 90° and then extends symmetrically to both sides, forming a Jerusalem cross structure. The length of the extended portion is... l2 The transparent dual-frequency reflective array antenna has been transformed into a Type 2 structure, as can be seen in Figure 5(c). l2 The length is the length of the first cross dipole structure after bending the end of the first cross dipole structure by 90° and continuing to extend it. l1 Before the change reached 7.5mm, l2 It is always 0. Taking a certain fixed state as an example, in Figure 5(c) l1 =7.5mm, l2=3mm. The dielectric material below the unit is still quartz glass with a thickness of h=1mm, and the bottom layer is still a transparent resistive film with a sheet resistance of 0.06Ω, serving as the ground plane for the antenna unit.

[0036] The transparent resistive film used in this embodiment is product model EMI-YXI60T-02, which is compatible with transparent reflective array antenna floor.

[0037] When designing the low-frequency reflective array antenna element 1, the phase compensation range of the individual first crossed dipole structure and Jerusalem cross structure was very small, failing to achieve 360° phase coverage. However, after placing the high-frequency reflective array antenna element 2 around the low-frequency reflective array antenna element 1, the phase compensation range was significantly improved. This indicates that the high-frequency element acts as a coupling patch for the low-frequency element, achieving structural reuse. The phase shift curve and co-polarization reflection coefficient diagram of the two-degree-of-freedom low-frequency element were simulated, as shown below. Figure 6 and Figure 7 As shown. It can be seen that when l1 When the frequency changes, the common polarization reflection coefficient of the unit remains above -0.8 dB at 13.2 GHz. l2 When the elements change, the common polarization reflection coefficient of the element remains above -0.2dB at 13.2GHz, and the phase compensation range of the two element changes covers 360°, providing good support for the design of subsequent antennas.

[0038] The transparent dual-frequency reflective array antenna proposed in this invention has an array size of 152mm × 152mm, corresponding to a first cross dipole structure size of 19mm × 19mm for the low-frequency reflective array antenna element 1. In the simulation, both the low-frequency feed 3 and the high-frequency feed 4 use standard 15dBi gain horn antennas. To avoid mutual obstruction between the feeds, the high-frequency feed 4 is placed directly above the array, while the low-frequency feed 3 is rotated 15° along the -x-axis. To prevent the horn from obstructing the antenna beam, the high-frequency beam pointing direction is designed as (90°, 30°), and the low-frequency beam pointing direction is designed as (0°, 30°). The high-to-low frequency focal diameter ratio is optimized to 0.9.

[0039] Another embodiment of the present invention provides a phase compensation method for the transparent dual-frequency reflective array antenna, as follows: The dual-band reflective array antenna element is initially a Type 1 structure, and the length of the first cross dipole structure of the low-frequency reflective array antenna element 1 is... l1 The period of the high-frequency reflective array antenna element 2 is smaller than that of the dual-band reflective array antenna element, and the width of the inner square ring is changed by the high-frequency reflective array antenna element 2. w2 and the length of the second cross dipole structure w3 Phase compensation is performed; when the length of the first cross dipole structure of the low-frequency band reflective array antenna element 1 is... l1When the change reaches the period size of the dual-band reflective array antenna element, the dual-band reflective array antenna element becomes a Type 2 structure. After rotating the fine metal wire end of the first cross dipole structure by 90°, it extends symmetrically to both sides to form a Jerusalem cross structure for phase compensation. Phase required for specifying beam direction Calculate according to the following formula:

[0040] In the formula, The straight-line distance between the dual-band reflective array antenna elements and the feed source at different locations; Let be the wave number in free space. As a reference phase, This represents the position coordinates of a dual-band reflective array antenna element in Cartesian coordinates. Indicates the azimuth angle of the beam direction. This indicates the elevation angle of the beam direction.

[0041] In the phase compensation process of a transparent dual-frequency reflective array antenna, the required compensation phase for each element of the array is first calculated according to the phase compensation formula. Then, the reflection phase data of elements of different sizes are imported into MATLAB software. During modeling, the required compensation phase is automatically modeled by matching it with the corresponding element size. At the same time, the boundary conditions, field monitors and frequencies required for simulation are designed. After the modeling is completed, the feed source is imported and the excitation port is set to start the simulation.

[0042] Based on the phase compensation formula, the phase distributions requiring compensation at various locations of the high- and low-frequency band reflective array antenna elements, calculated in MATLAB, are shown in Figures 8(a) to 8(c). The phase compensation of the low-frequency band reflective array antenna element 1 is achieved through the first cross dipole structure... l1 and l2 The length variation is controlled, and the phase compensation of the high-frequency reflective array antenna element 2 is achieved through the width of the inner square ring in the element. w2 The length is controlled.

[0043] The low-frequency array element distribution generated in Matlab is shown in Figures 8(a) and 8(b). The color changes of the elements in the two figures correspond to... l1 and l2 The length variation can be seen within the phase compensation range of the dual-band reflective array antenna element with a Type 1 structure. l2 The length remains 0, corresponding to the dark blue in Figure 8(b). When the dual-band reflective array antenna element exceeds the element phase compensation range of the Type 1 structure, the length... l2 Change began, and l1 The length is kept at 7.5mm.

[0044] The array element distribution of the high-frequency reflective array antenna is shown in Figure 8(c). The color changes in the figure correspond to... w2 The length variation, and the simulated distribution of antenna array elements after automatic modeling are as follows: Figure 9 As shown.

[0045] The transparent dual-frequency reflector array of the present invention was simulated as a whole. The low-frequency simulation range was 11.2 GHz to 15.2 GHz, and the high-frequency simulation range was 25 GHz to 28 GHz. The E-plane and H-plane radiation patterns of the transparent dual-frequency reflector array antenna at 13.2 GHz are shown in Figures 10(a) and 10(b). It can be seen that the sidelobe level of the antenna at 13.2 GHz is consistently less than -15 dB, and the cross-polarization level is consistently less than -25 dB. The E-plane and H-plane radiation patterns of the transparent dual-frequency reflector array antenna at 26.5 GHz are shown in Figures 11(a) and 11(b). It can be seen that the sidelobe level of the antenna at 26.5 GHz is consistently less than -15 dB, and the cross-polarization level is consistently less than -25 dB. The gain curves of the transparent dual-frequency reflector array antenna at 11.2 GHz to 15.2 GHz and at 25 GHz to 28 GHz are shown in Figures 11(a) and 11(b), respectively. Figure 12 and Figure 13 As shown in the figure, the peak gain at low frequencies is 22.1 dBi, the 1-dB gain bandwidth is about 14.8%, and the 3-dB gain bandwidth is about 22.7%. The peak gain at high frequencies is 27.4 dBi, the 1-dB bandwidth is about 9.4%, and the 3-dB gain bandwidth is greater than 11.3%.

[0046] The simulation results show that the antenna of this application exhibits excellent radiation pattern performance in both frequency bands, with outstanding radiation stability and anti-interference capabilities. The simulation range was set to 11.2 GHz–15.2 GHz for the low-frequency band and 25 GHz–28 GHz for the high-frequency band. Representative operating frequencies (13.2 GHz for the low-frequency band and 26.5 GHz for the high-frequency band) were selected for radiation pattern testing. The simulation results show that at 13.2 GHz, the sidelobe levels of the antenna's E-plane and H-plane radiation patterns are consistently less than -15 dB, and the cross-polarization level is consistently less than -25 dB. Similarly, at 26.5 GHz, the sidelobe levels of the antenna's E-plane and H-plane radiation patterns are consistently less than -15 dB, and the cross-polarization level is consistently less than -25 dB. A sidelobe level below -15dB indicates concentrated antenna radiation energy, effectively reducing sidelobe interference and improving signal transmission directivity and anti-interference capability. A cross-polarization level below -25dB indicates high antenna polarization purity, effectively suppressing polarization interference and ensuring the stability and reliability of dual-band signal transmission. This performance advantage is attributed to the rational layout of the high and low frequency antenna elements (low-frequency elements centered and high-frequency elements arranged in a staggered pattern around them), and the composite structure design of the outer square ring, inner square ring, and second cross dipole of the high-frequency elements. This effectively optimizes the antenna's radiation characteristics and solves the technical problems of radiation dispersion and severe polarization interference that are common in traditional dual-band antennas.

[0047] Secondly, the antenna in this application possesses high gain and wide gain bandwidth in both frequency bands, meeting the communication needs of various scenarios. The gain curves obtained from simulations show that the peak gain in the low-frequency band (11.2GHz-15.2GHz) reaches 22.1dBi, with a 1-dB gain bandwidth of approximately 14.8% and a 3-dB gain bandwidth of approximately 22.7%; while in the high-frequency band (25GHz-28GHz), the peak gain reaches 27.4dBi, with a 1-dB gain bandwidth of approximately 9.4% and a 3-dB gain bandwidth greater than 11.3%. The high peak gain (22.1dBi in the low-frequency band and 27.4dBi in the high-frequency band) indicates strong signal reception and reflection capabilities, enabling long-distance, high-quality signal transmission. The wide gain bandwidth (22.7% in the low-frequency band and greater than 11.3% in the high-frequency band) demonstrates excellent gain stability in both frequency bands, allowing the antenna to adapt to communication signals of different frequencies and meet the needs of multi-protocol, multi-band collaborative communication. The key to achieving this effect lies in the dual-degree-of-freedom phase modulation design of this application—the low-frequency unit can be extended from a cross dipole structure to a Jerusalem cross structure, and the high-frequency unit achieves precise phase modulation by adjusting the size of the inner square ring and the second cross dipole, effectively widening the phase compensation range and optimizing the antenna's gain and bandwidth performance. At the same time, combined with the low-loss characteristics of the transparent metal mesh resistive film ground plane, energy loss during signal transmission is reduced, further improving the antenna gain.

[0048] Simulation data fully demonstrates that the transparent dual-band reflective array antenna of this application possesses excellent radiation pattern performance, high peak gain, and wide gain bandwidth in both frequency bands. It not only solves the shortcomings of traditional transparent reflective array antennas that only support a single frequency band and have poor frequency band adaptability, but also overcomes the problems of poor light transmission and radiation performance of conventional dual-band reflective array antennas, achieving an organic combination of optical transparency, dual-band compatibility, and excellent electromagnetic performance. Its outstanding technical effects can fully meet the practical needs of multi-band communication and radar detection in transparent scenarios such as smart city construction, vehicle observation windows, and building glass.

[0049] Finally, it should be noted that the above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical details; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A transparent dual-frequency reflective array antenna, characterized in that, It includes a transparent medium and dual-band reflective array antenna elements arranged and laid on the transparent medium. The bottom surface of the transparent medium is covered with a floor made of transparent metal mesh resistive film. The dual-band reflective array antenna unit includes a low-frequency reflective array antenna unit (1) and a high-frequency reflective array antenna unit (2), which are arranged in an alternating array. The low-frequency reflective array antenna unit (1) is located at the center of each dual-band reflective array antenna unit, and the high-frequency reflective array antenna units (2) are distributed around the low-frequency reflective array antenna unit (1). The low-frequency reflective array antenna unit (1) adopts a first cross dipole structure made of fine metal wire, which can be extended to form a Jerusalem cross structure. The high-frequency reflective array antenna unit (2) includes an outer square ring, an inner square ring, and a second cross dipole structure, all made of fine metal wire from the outside to the inside. Phase modulation is achieved by changing the size of the inner square ring and the second cross dipole structure. The dual-band reflective array antenna elements are equipped with a low-frequency feed (3) and a high-frequency feed (4) above them.

2. The transparent dual-frequency reflective array antenna according to claim 1, characterized in that, The width of the fine metal wire is <50μm.

3. The transparent dual-frequency reflective array antenna according to claim 1, characterized in that, The size of the outer ring is fixed, while the width of the inner ring changes during phase adjustment. w2 The length of the second cross dipole structure is changed. w3 follow w2 change.

4. The transparent dual-frequency reflective array antenna according to claim 1, characterized in that, The sheet resistance of the transparent metal mesh resistive film is 0.06Ω.

5. The transparent dual-frequency reflective array antenna according to claim 1, characterized in that, The transparent medium is quartz glass with a relative permittivity of 3.75, a loss tangent of 0.0004, and a thickness of h=1mm.

6. The transparent dual-frequency reflective array antenna according to claim 1, characterized in that, Length of the first cross dipole structure l1 When the change reaches the period size of the dual-band reflective array antenna element, the end of the fine metal wire is rotated 90° and then extended symmetrically to both sides, with the length of the extended portion being... l2 This forms the Jerusalem cross structure.

7. The transparent dual-frequency reflective array antenna according to claim 1, characterized in that, Both the low-frequency feed (3) and the high-frequency feed (4) are standard gain horn antennas with a gain of 15dBi.

8. The transparent dual-frequency reflective array antenna according to claim 7, characterized in that, The high-frequency feed (4) is placed directly above the dual-band reflective array antenna unit arranged in the array, and the low-frequency feed (3) is placed by rotating it 15° along the -x axis.

9. The transparent dual-frequency reflective array antenna according to claim 7, characterized in that, The high-frequency feed (4) is designed to point the high-frequency beam at (90°, 30°), and the low-frequency feed (3) is designed to point the low-frequency beam at (0°, 30°).

10. A phase compensation method for a transparent dual-frequency reflective array antenna as described in any one of claims 1 to 9, characterized in that, The dual-band reflective array antenna element is initially a Type 1 structure, and the length of the first cross dipole structure of the low-frequency reflective array antenna element (1) is... l1 The period of the high-frequency reflective array antenna element (2) is smaller than that of the dual-band reflective array antenna element, and the width of the inner square ring of the high-frequency reflective array antenna element (2) is changed. w2 and the length of the second cross dipole structure w3 Phase compensation is performed; when the length of the first cross dipole structure of the low-frequency band reflective array antenna element (1) is... l1 When the change reaches the period size of the dual-band reflective array antenna element, the dual-band reflective array antenna element becomes a Type 2 structure. After rotating the fine metal wire end of the first cross dipole structure by 90°, it extends symmetrically to both sides to form a Jerusalem cross structure for phase compensation. Phase required for specifying beam direction Calculate according to the following formula: In the formula, The straight-line distance between the dual-band reflective array antenna elements and the feed source at different locations; Let the wave number be in free space. As a reference phase, This represents the position coordinates of a dual-band reflective array antenna element in Cartesian coordinates. Indicates the azimuth angle of the beam direction. This indicates the pitch angle of the beam direction.

Images