Low frequency band planar passive scattering radar echo enhancer

Abstract

This invention relates to the field of radar echo enhancer technology, and more particularly to a low-frequency band planar passive scattering radar echo enhancer. The enhancer comprises two planar square helical metal strips that spiral in opposite directions from the same center point, together forming a planar double-helix structure with an overall square frame. This enhancer can effectively enhance low-frequency (P-band) radar echoes within a miniaturized size, and the double-helix structure within a square frame provides a structurally regular, easily fabricated, and integrated enhancer structure for radar echo enhancement.

Description

Technical Field

[0001] This invention relates to the field of radar echo enhancer technology, and more particularly to a low-frequency planar passive scattering radar echo enhancer. Background Technology

[0002] In applications such as radar system testing, military exercises, and small target detection, RCS enhancers are often used to simulate the radar reflection characteristics of specific targets or improve the detection range of small targets. RCS enhancers are mainly divided into two categories: active and passive. Although active enhancers have a wider bandwidth, they are complex in structure, require a power supply, are costly, and their reliability is limited by electronic components. Passive enhancers, such as corner reflectors and Luneburg lenses, have the advantages of simple structure, no power supply required, and high reliability, but in low-frequency applications, they often face the challenges of large size and fixed, non-adjustable operating frequency.

[0003] Frequency selective surfaces (FSS) and various resonant structures are effective means of achieving passive RCS modulation. Traditional planar spiral structures, as a common type of resonator, have resonant frequencies primarily determined by their external profile dimensions, typically following a rule that the external profile dimension is approximately 0.18 to 0.20 times the operating wavelength. This results in a very large physical size (generally at least 300 mm) required for operation in lower frequency bands (e.g., P-band 230-1000 MHz), making it difficult to meet the miniaturization and integration requirements of modern equipment. Conversely, if the size is reduced, operation is limited to higher frequency bands, failing to meet the low-frequency enhancement requirements. Summary of the Invention

[0004] The purpose of this invention is to provide a low-frequency planar passive scattering radar echo enhancer, which solves the problem of large physical size of existing low-frequency echo enhancers.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a low-frequency band planar passive scattering radar echo enhancer, characterized in that it comprises two planar square spiral metal strips, which originate from the same center point and spiral in opposite directions, together forming a planar double spiral structure with an overall outer contour of a square frame.

[0006] Optionally, the metal arm of the planar square spiral metal strip is a straight arm.

[0007] Optionally, the metal arms of the planar square spiral metal strip are periodically bent, zigzag-arm slow-wave structures.

[0008] Optionally, the bending parameters of the zigzag-arm slow-wave structure include bending period and / or bending amplitude, and the resonant frequency of the amplifier can be adjusted by changing the bending period and / or bending amplitude of the zigzag-arm slow-wave structure.

[0009] Optionally, the shape of the periodically bent zigzag arm slow wave structure is a sine curve or a triangular wave.

[0010] Optionally, the width of the metal arm is 3 to 8 mm.

[0011] Optionally, the spacing between adjacent metal arms in the planar double helix structure is 5~10mm.

[0012] Optionally, the outer contour dimensions of the planar double helix structure are 200mm × 200mm.

[0013] The above-described technical solution of the present invention has the following advantages: The present invention provides a low-frequency band planar passive scattering radar echo enhancer, comprising two planar square helical metal strips. These two strips originate from the same center point and spiral in opposite directions, collectively forming a planar double-helix structure with an overall square frame. This enhancer effectively enhances low-frequency (P-band) radar echoes within a miniaturized size. Furthermore, the double-helix structure within a square frame provides a structurally regular, easily fabricated, and integrated enhancer structure for radar echo enhancement.

[0014] This invention provides another low-frequency planar passive scattering radar echo enhancer, in which the metal arms of the planar square helical metal strip are periodically bent zigzag-arm slow-wave structures. This enhancer can effectively enhance low-frequency (P-band) radar echoes within a miniaturized size, while altering the fixed relationship between the resonant frequency and physical dimensions by introducing the zigzag-arm slow-wave structure. While maintaining the external contour dimensions completely unchanged, the resonant frequency can be flexibly designed and adjusted simply by adjusting the bending parameters of the zigzag arms (such as period and amplitude), thus breaking through the design limitations of traditional planar helical structures with their 'fixed frequency in shape'. Attached Figure Description

[0015] The accompanying drawings are provided for illustrative purposes only, and the proportions and quantities of the components in the drawings may not be consistent with the actual product.

[0016] Figure 1 This is a schematic diagram of a low-frequency planar passive scattering radar echo enhancer according to Embodiment 1 of the present invention; Figure 2 yes Figure 1 A schematic diagram of the simulation results of the intensifier; Figure 3 This is a schematic diagram of a low-frequency planar passive scattering radar echo enhancer according to Embodiment 2 of the present invention; Figure 4 yes Figure 3 A schematic diagram of the simulation results of the intensifier.

[0017] In the picture: 1: Planar square spiral metal strip; 11: Metal arm. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. 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.

[0019] Example 1 like Figure 1 As shown, the low-frequency planar passive scattering radar echo enhancer provided in this embodiment of the invention is a planar double-helix structure with an overall outer contour of a square frame. This planar double-helix structure includes two planar square helical metal strips 1, which originate from the same center point and spiral in opposite directions (e.g., one clockwise and the other counterclockwise), together forming a planar double-helix structure with an overall outer contour of a square frame. Each planar square helical metal strip 1 consists of multiple sequentially connected metal arms 11.

[0020] In this embodiment, the metal arms 11 of the two spiral metal strips 1 are both straight arms, that is, from the center to the outermost edge, each segment of the spiral path is a straight structure.

[0021] The width (W) of the metal arm is 5 mm. The spacing (L) between two adjacent spiral metal strips is 10 mm. The overall outer dimensions of the structure are 200 mm × 200 mm.

[0022] The single-station RCS (radar cross section) was simulated and analyzed in electromagnetic simulation software, and the resulting curve of RCS as a function of frequency is shown below. Figure 2 As shown in the figure. Simulation results show that the enhancer exhibits a significant resonance peak at approximately 0.29 GHz, and its RCS value is significantly enhanced. This enhancer can effectively enhance low-frequency (P-band) radar echoes with a miniaturized size.

[0023] In this embodiment, two adjacent metal arms are arranged in parallel.

[0024] It is worth noting that the width of the metal arm (3-8 mm) and the spacing between adjacent metal arms (5-10 mm) in this invention are preferred ranges verified through extensive simulations, achieving a good balance between miniaturization, manufacturing feasibility, and electromagnetic performance. Those skilled in the art, after reading this invention, can select other dimensions based on actual needs under the guidance of this principle; all such variations should fall within the protection scope of this invention.

[0025] Example 2 like Figure 3 As shown, the enhancer in this second embodiment is identical to that in the first embodiment in all external constraints: the overall outer contour dimensions of the structure are 200mm × 200mm, the metal arm width is 5mm, and the spacing between adjacent metal arms is 10mm. The main difference is that the metal arms of the two planar square spiral metal strips are no longer straight arms, but rather periodically bent zigzag slow-wave structures. In this embodiment, the bending is modulated using triangular waves. That is, the originally straight spiral arms are designed to periodically meander along their extension direction in the shape of triangular waves.

[0026] The structure was analyzed under exactly the same simulation conditions. Figure 4 The simulation results are presented and compared with the results of Example 1 (see [link]). Figure 2 A comparison was then made. It can be clearly seen that, with the physical dimensions remaining absolutely unchanged, simply changing the straight arm to a triangular wave zigzag arm significantly shifted the resonant frequency of the amplifier, moving it from 0.29 GHz to approximately 0.39 GHz. This also proves that the "zigzag arm" structure itself has the ability to alter resonant characteristics.

[0027] Compared to Example 1, Example 2 allows for flexible design and adjustment of the resonant frequency by adjusting the bending parameters (such as period and amplitude) of the bend arm, thus breaking through the design limitation of "fixed frequency in shape" of traditional planar spiral structures.

[0028] In this embodiment, the shape of the zigzag slow-wave structure with the periodically bent metal arm can be a sine curve or a triangular wave.

[0029] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that not every embodiment contains only one independent technical solution, and in the absence of conflict between solutions, the various technical features mentioned in each embodiment can be combined in any way to form other implementation methods that can be understood by those skilled in the art.

[0030] Furthermore, without departing from the scope of the present invention, modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some of the technical features, shall 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.

Claims

1. A low-frequency band planar passive scattering radar echo enhancer, characterized in that: It includes two planar square spiral metal strips, which start from the same center point and spiral in opposite directions, together forming a planar double spiral structure with an overall outer contour of a square frame.

2. The low-frequency planar passive scattering radar echo enhancer according to claim 1, characterized in that: The metal arms of the planar square spiral metal strip are straight arms.

3. The low-frequency planar passive scattering radar echo enhancer according to claim 1, characterized in that: The metal arms of the planar square spiral metal strip are periodically bent, zigzag-arm slow-wave structures.

4. The low-frequency planar passive scattering radar echo enhancer according to claim 3, characterized in that: The bending parameters of the zigzag-arm slow-wave structure include the bending period and / or bending amplitude. The resonant frequency of the amplifier can be adjusted by changing the bending period and / or bending amplitude of the zigzag-arm slow-wave structure.

5. The low-frequency planar passive scattering radar echo enhancer according to claim 3, characterized in that: The shape of the periodically bent, zigzag-arm slow-wave structure is a sine curve or a triangular wave.

6. The low-frequency planar passive scattering radar echo enhancer according to claim 1, characterized in that: The width of the metal arm is 3~8mm.

7. The low-frequency planar passive scattering radar echo enhancer according to claim 1, characterized in that: The spacing between adjacent metal arms in the planar double helix structure is 5~10mm.

8. The low-frequency band planar passive scattering radar echo enhancer according to claim 1, characterized in that: The outer contour dimensions of the planar double helix structure are 200mm × 200mm.

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