Frequency selective surface and communication system

Abstract

A frequency selective surface includes a plurality of multi-band array units arranged periodically. Each multi-band array unit includes: a reflective unit disposed on the upper surface of a substrate, the reflective unit including a first metal rectangular patch, each of the four sides of the first metal rectangular patch having an L-shaped unit hollowed out, such that each of the four sides of the first metal rectangular patch retains a long strip-shaped branch with one end suspended, forming a windmill shape; and a transmission unit disposed on the upper surface of the substrate, the transmission unit including a second metal rectangular patch, the center of the second metal rectangular patch having a Jerusalem cross unit hollowed out. The first metal rectangular patch of the reflective unit and the second metal rectangular patch of the transmission unit are the same size and overlap each other, reducing the size of the frequency selective surface and meeting the miniaturization requirements.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic wave technology, and more particularly to a frequency selective surface and communication system. Background Technology

[0002] A frequency selective surface (FSS) is a two-dimensional periodic array structure that allows electromagnetic waves to pass through a specific frequency band with no or low loss, while shielding and reflecting electromagnetic waves outside that band. It effectively controls the transmission and reflection of electromagnetic waves, similar to a space filter. Due to its unique filtering characteristics, FSS can be widely used in electromagnetic protection, electromagnetic compatibility, antennas, and filters. Satellite communication mainly refers to radio communication between earth stations or between earth stations and spacecraft via communication satellites. The main operating frequency bands for satellite communication are the centimeter wave band, with a frequency range of 3-30 GHz. This band corresponds to the IEEE S (2-4 GHz), C (4-8 GHz), Ku (12-18 GHz), K (18-27 GHz), and Ka (26.5-40 GHz) bands.

[0003] Satellite communication operates over a wide range of frequency bands, but existing frequency selection surfaces used for satellite communication are single-band, with limited filtering bands and poor structural stability. They cannot meet the requirements of more scenarios and higher performance. Furthermore, the existing FSS structural units are too large to meet the current demand for miniaturized structures. Summary of the Invention

[0004] In view of this, the present invention provides a frequency selective surface that meets the requirements of miniaturized structure and has multiple operating frequency bands, thereby improving the application range.

[0005] This invention provides a frequency selective surface comprising a plurality of multi-band array units arranged periodically. Each multi-band array unit includes: a reflective unit disposed on the upper surface of a substrate, the reflective unit comprising a first metal rectangular patch, wherein each of the four sides of the first metal rectangular patch has an L-shaped unit hollowed out, such that each of the four sides of the first metal rectangular patch retains a long strip-shaped branch with one end suspended, forming a windmill shape; and a transmission unit disposed on the upper surface of the substrate, the transmission unit comprising a second metal rectangular patch, wherein the center of the second metal rectangular patch has a Jerusalem cross unit hollowed out. The first metal rectangular patch of the reflective unit and the second metal rectangular patch of the transmission unit are the same size and overlap each other.

[0006] Preferably, the periodic arrangement is a matrix arrangement.

[0007] Preferably, the operating frequency band of the reflective unit is the Ku or Ka band; the operating frequency band of the transmission unit is the K band.

[0008] Preferably, the length of each multi-band array unit is less than half the wavelength of the center frequency of the Ku band.

[0009] Preferably, the length of the L-shaped unit of the reflective unit is one-quarter of the wavelength of the center frequency of the Ku band.

[0010] Preferably, the length of one-quarter of the Jerusalem cross unit is one-third of the wavelength of the center frequency of the K band.

[0011] Preferably, by adjusting the length of the L-shaped unit, the center frequency of the reflective unit operating in the Ku band is adjusted.

[0012] Preferably, the Jerusalem cross unit is a rotationally symmetric structure, comprising: a cross-shaped hollow portion and four rectangular hollow portions respectively perpendicularly disposed at the four ends of the cross-shaped hollow portion.

[0013] Preferably, the center frequency of the transmission unit operating in the K-band is adjusted by adjusting the length of the cross-shaped cutout; the center frequency of the reflection unit operating in the Ka-band is adjusted by adjusting the width of the rectangular cutout.

[0014] The present invention also provides a communication system comprising the frequency selective surface described in any of the preceding claims.

[0015] Compared to existing technologies, the frequency selective surface provided by the embodiments of the present invention includes a plurality of periodically arranged multi-band array units. Each multi-band array unit includes a reflection unit and a transmission unit. The reflection unit and the transmission unit are both disposed on the upper surface of the substrate, and the reflection unit and the transmission unit overlap each other, thereby reducing the size of the frequency selective surface and meeting the miniaturization requirements. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a frequency selective surface according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the structure of a multi-band array unit of a frequency selective surface according to an embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the structure of a reflective unit of a frequency selective surface according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the structure of a transmission unit of a frequency selective surface according to an embodiment of the present invention.

[0019] Figure 5 This is a schematic diagram showing the curve of the center frequency of the operating frequency band of a frequency selective surface in the Ku band as a function of the bandwidth G, according to an embodiment of the present invention.

[0020] Figure 6 This is a schematic diagram showing the curve of the center frequency of the operating frequency band of a frequency selective surface in the K-band as a function of the spacing A, according to an embodiment of the present invention.

[0021] Figure 7 This is a schematic diagram showing the curve of the center frequency of the operating frequency band of a frequency selective surface in the Ka band as a function of the bandwidth D, according to an embodiment of the present invention.

[0022] Figure 8 This is a schematic diagram of a transmission simulation measurement of a frequency-selective surface according to an embodiment of the present invention.

[0023] Figure 9 This is a schematic diagram of a transmission simulation measurement of a frequency-selective surface according to an embodiment of the present invention.

[0024] Figure 10 The diagram shows the ideal curve and the simulated curve of the S-parameter of the frequency-selective surface according to an embodiment of the present invention.

[0025] Explanation of main component symbols 1: Frequency Selective Surface 10: Multi-band array unit 20: Upper surface 100: Reflection unit 101: Transmission Unit P1: First metal patch A1: L-shaped unit L: Long, narrow branch L1: Length L2: Length P2: Second metal patch A2: Jerusalem Cross Unit A21: Cross-shaped hollow section A3: Metal block G: Width D: Width A: Spacing A211: Part One A212: Part Two A221-A224: Rectangular cutout Ant1-Ant2: Antenna S1~S4: Curves The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. Detailed Implementation

[0026] To facilitate understanding and implementation of this invention by those skilled in the art, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that this invention provides many applicable inventive concepts, which can be implemented in various specific forms. Those skilled in the art can utilize the details described in these or other embodiments, as well as other available structural, logical, and electrical variations, to implement the invention without departing from its spirit and scope.

[0027] This specification provides different embodiments to illustrate the technical features of different implementations of the invention. The configuration of elements in the embodiments is for illustrative purposes only and is not intended to limit the invention. Furthermore, the repetition of some reference numerals in the embodiments is for simplification and does not imply any correlation between different embodiments. The same element numbers used in the illustrations and specification represent the same or similar components. The illustrations in this specification are simplified and not drawn to scale.

[0028] Furthermore, in describing some embodiments of the present invention, the specification describes the method and / or procedure of the present invention in a specific order of steps. However, since the method and procedure are not necessarily performed according to the specific order of steps described, they are not limited to the specific order of steps. Those skilled in the art will understand that other orders are also possible implementations. Therefore, the specific order of steps described in the specification is not intended to limit the scope of the patent application. Moreover, the scope of the present invention for the method and / or procedure is not limited to the order of execution steps written therein, and those skilled in the art will understand that adjusting the order of execution steps does not depart from the spirit and scope of the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Some embodiments of the invention are described in detail below with reference to the accompanying drawings.

[0030] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a frequency selective surface according to an embodiment of the present invention. In this embodiment, the frequency selective surface 1 is mainly used in communication systems, such as low-Earth orbit satellite communication systems and radar systems.

[0031] like Figure 1As shown, the frequency selection surface 1 includes a plurality of multi-band array elements 10 arranged periodically. The multi-band array elements 10 have identical structures, and this periodic arrangement is preferably a matrix arrangement. Figure 1 As shown in the illustration, the frequency selection surface 1 is arranged in a 4x4 matrix as an example in this embodiment, but it is not limited to this. In practical applications, it can be expanded to the required matrix size according to communication needs.

[0032] Combination Figure 2 , Figure 2 This is a schematic diagram of the structure of a multi-band array unit of a frequency selective surface according to an embodiment of the present invention. Figure 2 As shown, the multi-band array unit 10 includes a reflection unit 100 and a transmission unit 101. The reflection unit 100 is disposed on the upper surface 20 of the substrate, and the transmission unit 101 is also disposed on the upper surface 20 of the substrate. The reflection unit 100 and the transmission unit 101 overlap to form a single-layer multi-band array unit 10 with integrated reflection and transmission, which reduces the size of the multi-band array unit 10 and meets the miniaturization requirements.

[0033] Specifically, in combination Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the structure of a frequency-selective surface reflection unit 100 according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the structure of a transmission unit 101 of a frequency selective surface according to an embodiment of the present invention. The reflection unit 100 includes a first rectangular metal patch P1, with an L-shaped unit A1 hollowed out on each of its four sides, such that each of the four sides of the first rectangular metal patch P1 retains a long strip-shaped branch L with one end suspended, forming a windmill shape. The transmission unit 101 includes a second rectangular metal patch P2, with a Jerusalem cross unit A2 hollowed out at the center of the second rectangular metal patch P2. (Return to Appendix) Figure 2 The first rectangular metal patch P1 of the reflective unit 100 and the second rectangular metal patch P2 of the transmissive unit 101 are the same size and overlap each other. The Jerusalem cross unit A2 and the L-shaped unit A1 do not intersect or overlap.

[0034] In this embodiment, the operating frequency band of the reflection unit 100 is the Ku and Ka bands, the operating frequency band of the transmission unit 101 is the K band, and the multi-band array unit 10 composed of the reflection unit 100 and the transmission unit 101 has operating frequency bands including the Ku, Ka and K bands, and has a wide range of applications.

[0035] In this embodiment, the length of the multi-band array unit 10 is less than half the wavelength of the center frequency of the Ku band, thereby avoiding the generation of grating lobes.

[0036] In this embodiment, the length L1 of the L-shaped unit A1 of the reflecting unit 100 is one-quarter of the wavelength of the center frequency of the Ku band. By adjusting the length of the L-shaped unit, the center frequency of the operating frequency band of the reflecting unit 100 in the Ku band is adjusted. Figure 2 When the length L1 of the L-shaped unit A1 changes, the width G of the metal block A3 also changes accordingly. That is, by adjusting the width G of the metal block A3, the center frequency of the reflective unit 100 operating in the Ku-band is adjusted. Combined with... Figure 5 , Figure 5 This is a schematic diagram showing the curve of the center frequency of a frequency selective surface operating in the Ku band as a function of bandwidth G, according to an embodiment of the present invention. Figure 5 As shown, when the width G of the metal block A3 is 0.25 mm, the center frequency of the reflective unit 100 operating in the Ku band is approximately 17.8 GHz; when the width G of the metal block A3 is 0.35 mm, the center frequency of the reflective unit 100 operating in the Ku band is approximately 17.3 GHz; when the width G of the metal block A3 is 0.45 mm, the center frequency of the reflective unit 100 operating in the Ku band is approximately 16.8 GHz; and when the width G of the metal block A3 is 0.55 mm, the center frequency of the reflective unit 100 operating in the Ku band is approximately 16.3 GHz. Within a certain range, the center frequency of the reflective unit 100 operating in the Ku band shifts towards lower frequencies as the width G of the metal block A3 increases.

[0037] In this embodiment, the length L2 of one-quarter Jerusalem cross unit A2 is one-third of the wavelength of the center frequency of the K-band. Adjusting the size of Jerusalem cross unit A2 can adjust the center frequency of the transmission unit 101 operating in the K-band and the center frequency of the reflection unit 100 operating in the Ka-band. Specifically, Jerusalem cross unit A2 has a rotationally symmetric structure, including a cross-shaped cutout A21 and four rectangular cutouts A221-A224 perpendicularly disposed at the four ends of the cross-shaped cutout A21. Cross-shaped cutout A21 includes a first part A211 and a second part A212, which are perpendicular to each other. The distance between the first part A211 and the rectangular cutouts A221 and A222 is A, and the distance between the second part A212 and the rectangular cutouts A223 and A224 is also A. The width of the rectangular cutouts A221-A224 is D. The center frequency of the transmission unit 101 operating in the K-band is adjusted by adjusting the length of the cross-shaped cutout A21, which is equivalent to adjusting the size of the spacing A. Figure 6 , Figure 6This is a schematic diagram showing the curve of the center frequency of a frequency-selective surface operating in the K-band as a function of spacing A, according to an embodiment of the present invention. Figure 6 As shown, when the spacing A is 0.85 mm, the center frequency of the transmission unit 101 operating in the K-band is approximately 22.8 GHz; when the spacing A is 1 mm, the center frequency is approximately 23.9 GHz; when the spacing A is 1.15 mm, the center frequency is approximately 25.1 GHz; and when the spacing A is 1.3 mm, the center frequency is approximately 26.2 GHz. Within a certain range, the center frequency of the transmission unit 101 operating in the K-band shifts towards higher frequencies as the spacing A increases.

[0038] In this embodiment, the center frequency of the reflective unit 100 operating in the Ka band is adjusted by regulating the width D of the rectangular cutouts A221-A224. Combined with... Figure 7 , Figure 7 This is a schematic diagram showing the curve of the center frequency of the operating frequency band of the frequency selective surface in the Ka band according to an embodiment of the present invention as a function of the width D. When the width D is 0.15 mm, the center frequency of the operating frequency band of the reflector unit 100 in the Ka band is approximately 29.1 GHz; when the width D is 0.175 mm, the center frequency of the operating frequency band of the reflector unit 100 in the Ka band is approximately 23.9 GHz; when the width D is 0.2 mm, the center frequency of the operating frequency band of the reflector unit 100 in the Ka band is approximately 30.1 GHz; and when the width D is 0.225 mm, the center frequency of the operating frequency band of the reflector unit 100 in the Ka band is approximately 31.7 GHz. Within a certain range, the center frequency of the Ka band shifts towards higher frequencies as the width D increases.

[0039] Please refer to the following: Figures 8-10 , Figure 8 This is a schematic diagram of a transmission simulation measurement of a frequency-selective surface according to an embodiment of the present invention. Figure 8 As shown, the frequency selective surface 1 is arranged in an 18x18 matrix. Antennas Ant1 and Ant2 are respectively d=200mm away from the frequency selective surface 1. The signals of antennas Ant1 and Ant2 are transmitted perpendicularly to the frequency selective surface 1. Figure 9 This is a schematic diagram of a frequency selective surface obliquely incident on a frequency selective surface according to an embodiment of the present invention. The frequency selective surface 1 is arranged in an 18x18 matrix. Ant1 and Ant2 are respectively d=200mm away from the frequency selective surface 1. The signals of antennas Ant1 and Ant2 are obliquely incident on the frequency selective surface 1 at a preset angle. Figure 10These are schematic diagrams of ideal and simulated curves of the S-parameters of a frequency-selective surface according to an embodiment of the present invention. Figure 10 As shown, curve S1 is the ideal curve of S-parameters for an oblique illumination scene, curve S2 is the ideal curve of S-parameters for a transmission scene, curve S3 is the simulated curve of S-parameters for an oblique illumination scene, and curve S4 is the simulated curve of S-parameters for a transmission scene. Curves S3 and S4 show trends consistent with curves S1 and S2, respectively, indicating stable performance of frequency selection surface 1. The center frequency of the operating band in the Ku band is approximately 16.3 GHz, the center frequency of the operating band in the K band is approximately 22.8 GHz, and the center frequency of the operating band in the Ka band is approximately 29.1 GHz. Frequency selection surface 1 has three operating bands, providing a wide range of applications.

[0040] Compared to existing technologies, the frequency selective surface provided by the embodiments of the present invention includes a plurality of periodically arranged multi-band array units. Each multi-band array unit includes a reflection unit and a transmission unit. The reflection unit and the transmission unit are both disposed on the upper surface of the substrate, and the reflection unit and the transmission unit overlap each other, thereby reducing the size of the frequency selective surface and meeting the miniaturization requirements.

[0041] Those skilled in the art should recognize that the above embodiments are merely illustrative of the present invention and are not intended to limit the present invention. Any appropriate changes and modifications made to the above embodiments within the essential spirit and scope of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A frequency-selective surface, characterized in that, It includes multiple multi-band array elements arranged periodically, each multi-band array element comprising: A reflective unit is disposed on the upper surface of the substrate. The reflective unit includes a first metal rectangular patch. An L-shaped unit is hollowed out on each of the four sides of the first metal rectangular patch, so that each of the four sides of the first metal rectangular patch retains a long strip-shaped branch with one end suspended, forming a windmill shape. A transmission unit is disposed on the upper surface of the substrate. The transmission unit includes a second metal rectangular patch, and a Jerusalem cross unit is hollowed out in the center of the second metal rectangular patch. The first rectangular metal patch of the reflective unit and the second rectangular metal patch of the transmissive unit are the same size and overlap each other.

2. The frequency selective surface as described in claim 1, characterized in that, The periodic arrangement is a matrix arrangement.

3. The frequency selectivity surface as described in claim 1, characterized in that: The operating frequency band of the reflection unit is the Ku and Ka bands; The operating frequency band of the transmission unit is the K-band.

4. The frequency selective surface as described in claim 3, characterized in that, The length of each multi-band array unit is less than half the wavelength of the center frequency of the Ku band.

5. The frequency selective surface as described in claim 3, characterized in that, The length of the L-shaped unit of the reflective unit is one-quarter of the wavelength of the center frequency of the Ku band.

6. The frequency selective surface as described in claim 3, characterized in that: The length of one-quarter of the Jerusalem Cross unit is one-third of the wavelength of the center frequency of the K-band.

7. The frequency selective surface as described in claim 3, characterized in that, By adjusting the length of the L-shaped unit, the center frequency of the reflective unit operating in the Ku band can be adjusted.

8. The frequency selective surface as described in claim 3, characterized in that: The Jerusalem cross unit is a rotationally symmetric structure, comprising: a cross-shaped hollow section and four rectangular hollow sections respectively perpendicularly disposed at the four ends of the cross-shaped hollow section.

9. The frequency selective surface as described in claim 8, characterized in that: The center frequency of the transmission unit's operating frequency band in the K-band can be adjusted by adjusting the length of the cross-shaped hollow section. The center frequency of the reflective unit's operating frequency band in the Ka band can be adjusted by adjusting the width of the rectangular cutout.

10. A communication system, characterized in that, Includes the frequency selective surface as described in any one of claims 1-9.

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