Adjustable two-dimensional beam scanning element grating leaky-wave antenna and analytical solution method

Abstract

The invention discloses an adjustable two-dimensional beam scanning element grating leaky-wave antenna and an analytic solution method, and belongs to the technical field of leaky-wave antennae, the antenna comprises an upper element light layer structure and a lower element light layer structure, an embedded liquid crystal is integrated in the lower element light layer, and a variable capacitance diode array is embedded in the upper element light layer. The analytic solution method comprises the following steps: S1, independently carrying out electromagnetic characteristic analysis on each element grating element, and decomposing a wave field into discrete space harmonics; s2, calculating and modeling adjustability provided by the embedded liquid crystal and the variable capacitance diode array; s3, integrating each individual analysis result into a complete multilayer electromagnetic model; and S4, verifying the analysis solution. According to the invention, scanning in two radiation directions of a horizontal plane and a vertical plane can be realized, the efficiency of a communication link in a complex urban environment can be improved by adaptively adjusting the beam direction, and the method is of great significance for realizing performance targets of high data rate, low delay, connection of a large number of devices and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of meta-grating leaky wave antennas, and in particular to an adjustable two-dimensional beam scanning meta-grating leaky wave antenna and an analytical solution method. Background Art

[0002] Traditionally, leaky wave antennas (LWAs) have limited scanning ranges in a single direction in the horizontal (azimuth) or vertical (elevation) plane, from backward radiation to broadside radiation, with two difficult regions. Backward radiation can be achieved through periodic structures, but broadside radiation poses additional obstacles. Periodic structures can be designed using periodic metamaterial units, enabling the leaky wave antenna to propagate in the backward and forward regions. By coupling the backward and forward regions at the broadside frequency, matching techniques can enable the leaky wave antenna to propagate at the broadside frequency, which is also known as frequency balance. Leaky wave antennas have important advantages such as a wide beam scanning range, a simple feed network, a low profile, and low cost. Due to their main characteristics, leaky wave antennas reduce the cost and complexity of antenna systems applied to aircraft, missiles, and satellites.

[0003] In modern communication systems, achieving full scanning angles using traditional leaky wave antennas requires a relatively wide frequency range, and some potential applications require broad beam scanning capabilities within the desired frequency range. In addition, leaky wave antennas are affected by the open-circuit stopband effect when scanning through broadside radiation, which leads to a certain mismatch in the input impedance when the frequency changes, causing all reflections at the signal source to add in phase. Therefore, frequency modulation (FM) analysis is interpreted as the coupling between frequency modulations at the broadside. Additionally, the main problem with traditional slotted leaky wave antennas lies in evaluating the mutual coupling admittance between these slotted antennas. For long slot cases, this reduces the antenna efficiency, and for surface wave modes, it is also a serious excitation problem that reduces the bandwidth at higher frequencies. Summary of the Invention

[0004] The objective of the present invention is to provide an adjustable two-dimensional beam scanning meta-grating leaky wave antenna and an analytical solution method, which can achieve scanning in two radiation directions in the horizontal and vertical planes. By adaptively adjusting the beam direction, the efficiency of communication links in complex urban environments can be improved, which is of great significance for achieving performance goals such as high data rate, low latency, and a large number of device connections.

[0005] To achieve the above objective, the present invention provides an adjustable two-dimensional beam scanning meta-grating leaky wave antenna, including two meta-optical layer structures, upper and lower. Each meta-optical layer includes a dielectric substrate at the bottom and meta-grating elements periodically arranged on the dielectric substrate; an embedded liquid crystal is integrated in the lower meta-optical layer, and the meta-grating elements in the lower layer are placed on top of the embedded liquid crystal; varactor diode arrays are embedded in the grating elements in the upper meta-optical layer.

[0006] The present invention also provides an analytical solution method for an adjustable two-dimensional beam scanning meta-grating leaky wave antenna, comprising the following steps:

[0007] S1. Using an analytical method, independently analyze the electromagnetic characteristics of each meta-optical layer, decompose the wave field into discrete spatial harmonics to understand the wave propagation and leakage mechanism;

[0008] S2. Calculate and model the tunability provided by the embedded liquid crystal and varactor diode array;

[0009] S3. Integrate the individual analysis results into a complete multi-layer electromagnetic model;

[0010] S4. Verify the analytical solution.

[0011] Preferably, in S1, the Floquet mode analysis is used for electromagnetic characteristic analysis.

[0012] Preferably, in S1, the calculation of Maxwell's equations is used during the analysis process, and particular attention is paid to the periodic boundary conditions imposed by the meta-grating elements.

[0013] Preferably, in S2, for the embedded liquid crystal, analyze its dielectric anisotropy at different voltages to quantify the effect of changing its orientation on wave propagation.

[0014] Preferably, in S2, for the varactor diode array, establish an equivalent circuit model, combine the applied voltage with the varactor diode, and calculate the resonance frequency and effective impedance of the upper-layer meta-grating elements.

[0015] Preferably, in S3, adopt the transmission line method or the coupled mode theory to predict the combined multi-layer response, calculate the beam angle, gain and radiation pattern; iteratively adjust the geometric shape, material properties and bias voltage of the embedded liquid crystal and varactor diode array to fine-tune the scanning performance of the antenna.

[0016] Preferably, in the simulation process, use a phased array radar system, a satellite Internet dynamically steerable antenna, and a next-generation wireless communication system that requires rapid beam direction switching to obtain various parameters.

[0017] Therefore, by adopting the above-mentioned adjustable two-dimensional beam scanning meta-grating leaky wave antenna and analytical solution method, the present invention can achieve scanning in two radiation directions of the horizontal and vertical planes, and can improve the efficiency of communication links in complex urban environments by adaptively adjusting the beam direction, which is of great significance for achieving performance goals such as high data rate, low latency and large number of device connections.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of an adjustable two-dimensional beam scanning meta-grating leaky wave antenna according to the present invention;

[0020] Figure 2 is a schematic diagram of the beam scanning radiation direction of an adjustable two-dimensional beam scanning meta-grating leaky wave antenna according to the present invention;

[0021] Figure 3 is an equivalent circuit diagram of an adjustable two-dimensional beam scanning meta-grating leaky wave antenna according to the present invention. Specific Embodiments

[0022] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" mean that the elements or items appearing before this term cover the elements or items listed after this term and their equivalents, without excluding other elements or items. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left", "right" are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0024] Embodiment 1

[0025] As Figure 1 shown, this embodiment provides an adjustable two-dimensional beam scanning meta-grating leaky wave antenna, including two meta-optical layer structures, upper and lower. Each meta-optical layer includes a dielectric substrate at the bottom and meta-grating elements periodically arranged on the dielectric substrate. The meta-grating elements allow the propagation of waves and the controlled leakage of electromagnetic energy, thereby forming a directional beam.

[0026] Embedded liquid crystal is integrated in the lower meta-optical layer. The dielectric constant of this material can be adjusted by applying an external electric field, thereby controlling the beam direction in one plane (such as vertical scanning). The meta-grating elements in the lower layer are placed on top of the embedded liquid crystal. Varactor diode arrays are embedded in the grating elements in the upper meta-optical layer. The capacitance of the electronic components whose capacitance can be electronically adjusted by changing the applied voltage can achieve fast and precise beam steering in another plane (such as horizontal scanning), as Figure 2As shown. The two layers are combined to achieve all-electronic real-time control of the beam direction, which is very suitable for advanced radars, satellite communications, and 5G / 6G wireless applications that require flexible directional control.

[0027] This embodiment also provides an analytical solution method for an adjustable two-dimensional beam scanning meta-grating leaky-wave antenna, including the following steps:

[0028] S1. Using an analytical method, independently analyze the electromagnetic characteristics of each meta-grating element, decompose the wave field into discrete spatial harmonics to understand the wave propagation and leakage mechanisms.

[0029] Perform electromagnetic characteristic analysis using analyses such as the Floquet mode, calculate using Maxwell's equations during the analysis, and pay particular attention to the periodic boundary conditions imposed by the meta-grating elements.

[0030] S2. Calculate and model the tunability provided by the embedded liquid crystal and varactor diode array.

[0031] For the embedded liquid crystal, analyze its dielectric anisotropy at different voltages to quantify the effect of changing its orientation on wave propagation.

[0032] For the varactor diode array, establish an equivalent circuit model, as Figure 3 shown, combine the applied voltage with the varactor diodes, and calculate the resonance frequency and effective impedance of the upper-layer meta-grating elements.

[0033] S3. Integrate the individual analysis results into a complete multi-layer electromagnetic model.

[0034] Adopt the transmission line method or the coupled mode theory to predict the combined multi-layer response, calculate the beam angle, gain, and radiation pattern. Iteratively adjust the geometry, material properties, and bias voltage of the embedded liquid crystal and varactor diode array to fine-tune the scanning performance of the antenna.

[0035] These accurately simulated real-time applications include phased array radar systems capable of quickly tracking moving targets, dynamically steerable satellite Internet antennas providing stable connections for aircraft and ships, and next-generation wireless communication systems that require rapid beam direction switching to efficiently serve mobile users to obtain various parameters.

[0036] S4. Verify the analytical solution.

[0037] Use electromagnetic simulation software such as CST Microwave Studio to verify the predicted behavior. The final antenna prototype needs to undergo extensive experimental verification to confirm the analytical predictions and ensure reliable beam scanning capabilities under actual operating conditions.

[0038] Therefore, by adopting the above-mentioned adjustable two-dimensional beam scanning meta-grating leaky-wave antenna and the analytical solution method, the present invention can achieve scanning in two radiation directions of the horizontal and vertical planes, and can improve the efficiency of communication links in complex urban environments by adaptively adjusting the beam direction, which is of great significance for achieving performance goals such as high data rate, low latency, and connection of a large number of devices.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An adjustable two-dimensional beam scanning meta-grating leaky wave antenna, characterized in that: It includes upper and lower metasurface layer structures. Each of the metasurface layers contains a dielectric substrate at the bottom and meta-grating elements periodically arranged on the dielectric substrate; an embedded liquid crystal is integrated in the lower metasurface layer, and the meta-grating elements in the lower layer are placed on top of the embedded liquid crystal; varactor diode arrays are embedded in the grating elements in the upper metasurface layer.

2. An analytical solution method for an adjustable two-dimensional beam scanning meta-grating leaky-wave antenna, characterized in that It includes the following steps: S1. Using an analytical method, perform electromagnetic characteristic analysis on each meta-grating element independently, decompose the wave field into discrete spatial harmonics to understand the wave propagation and leakage mechanisms; S2. Calculate and model the tunability provided by the embedded liquid crystal and the varactor diode arrays; S3. Integrate the individual analysis results into a complete multi-layer electromagnetic model; S4. Verify the analytical solution.

3. The analytical solution method of an adjustable two-dimensional beam scanning element grating leaky wave antenna according to claim 2, wherein: In S1, Floquet mode analysis is used for electromagnetic characteristic analysis.

4. The analytical solution method of an adjustable two-dimensional beam scanning meta-grating leaky wave antenna according to claim 2, characterized in that: In S1, calculations using Maxwell's equations are performed during the analysis, and particular attention is paid to the periodic boundary conditions imposed by the meta-grating elements.

5. The analytical solution method of an adjustable two-dimensional beam scanning meta grating leaky wave antenna according to claim 2, wherein: In S2, for the embedded liquid crystal, analyze its dielectric anisotropy at different voltages to quantify the effect of changing its orientation on wave propagation.

6. The analytical solution method of an adjustable two-dimensional beam scanning meta grating leaky wave antenna according to claim 2, wherein: In S2, for the varactor diode arrays, establish an equivalent circuit model, combine the applied voltage with the varactor diodes, and calculate the resonance frequency and effective impedance of the upper meta-grating elements.

7. An analytical solution method for an adjustable two-dimensional beam scanning element grating leaky wave antenna according to claim 2, characterized in that: In S3, use the transmission line method or coupled mode theory to predict the combined multi-layer response, and calculate the beam angle, gain, and radiation pattern; Iteratively adjust the geometries, material properties, and bias voltages of the embedded liquid crystal and the varactor diode arrays to fine-tune the scanning performance of the antenna.

8. The analytical solution method of an adjustable two-dimensional beam scanning element grating leaky-wave antenna according to claim 7, characterized in that: During the simulation process, a phased array radar system, a satellite internet dynamically steerable antenna, and a next-generation wireless communication system that requires rapid beam direction switching are used to obtain various parameters.

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