An actively controlled broadband wave-transmitting FSS material

Abstract

The present invention belongs to the field of electromagnetic wave control technology, and particularly relates to an actively regulated broadband wave-transparent FSS material. The present invention adopts a three-layer structure, and through the design of graphic upper and lower metal layers, supplemented by 8 varactor diodes, by adjusting the capacitance of the varactor diodes, the high bandwidth range of the dual passbands can be actively tuned at the same time, and both passband 1 and passband 2 have a broadband control range. The first transmission passband has a control range of 3.8GHz to 7.3GHz, with a controllable relative bandwidth range of 63.1%; the second transmission passband has a control range of 8.5GHz to 12.0GHz, with a controllable relative bandwidth range of 34.15%; the maximum insertion loss of the two passbands is 2.5dB, and the two transmission passbands can be regulated simultaneously to meet more application scenarios, and are insensitive to TE and TM polarizations. Its excellent active bandwidth control performance is applicable to the multi-frequency communication requirements of various agile radar antenna covers.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic wave control, and in particular relates to an actively regulated broadband wave-transparent FSS material. Background Art

[0002] Frequency selective surfaces (FSS) are widely used in radomes, wireless communications, and signal propagation control. While traditional FSSs can only provide fixed frequency bands, steerable multi-band FSSs are gaining attention due to their frequency band flexibility. However, the multi-band control range of existing active FSSs is insufficient, failing to cover a wide range of frequency bands and unable to achieve simultaneous tuning of multiple bands, limiting their application in complex communication systems. Therefore, developing an FSS that can achieve broadband wave transmission and simultaneous multi-band control is of great significance. Summary of the Invention

[0003] To address the aforementioned problems and shortcomings, and to address the limited multi-band control range and inability to simultaneously tune multiple frequency bands of existing frequency selective surfaces (FSSs), which limit their application in complex communication systems, the present invention provides an actively controlled broadband wave-transparent FSS material to achieve multi-band broadband control. The specific contents of the present invention are as follows:

[0004] An actively regulated broadband wave-transparent FSS material is composed of structural units arranged in a matrix with a tight periodic arrangement. The structural unit is a square with a period of P. The structural unit includes a three-layer structure of a first metal layer A, an intermediate dielectric layer, and a second metal layer B stacked in sequence from top to bottom.

[0005] The intermediate dielectric layer is a square dielectric layer with a side length of P (ie, the range of the structural unit period P), with a metal through hole provided at its center and metal through holes provided at its four corners with the vertices as the centers.

[0006] The first metal layer A includes: an equilateral right-angled triangle metal patch, a metal ring, a rectangular patch, a sun-shaped metal patch and a varactor diode.

[0007] There are four identical equilateral right-angled triangle metal patches in total, which are distributed on the four corners of the dielectric layer in the middle of the structural unit with their two right-angled sides adaptively aligned with one corner of the structural unit.

[0008] The metal ring is an irregular ring: a ring is constructed with the center of the square as the center, the outer ring intersects with the four sides of the square and the inner ring does not intersect, and the intersecting part of the outer ring is not counted; the corresponding ring area between the two points where one corner of the square intersects with the outer ring of the ring (that is, the ring area opposite to the equilateral right triangle metal patch) is replaced in the center with a rectangular metal strip with the same width as the ring, and the four corners of the square are replaced with four rectangular metal strips, and the rectangular metal strips do not touch the sides of the square or the base of the equilateral right triangle.

[0009] The rectangular patches are arranged in a one-to-one correspondence toward the center of the circle in such a way that their long sides overlap with the inner long sides of the rectangular metal strips, with a total of four.

[0010] The sun-shaped metal patch is formed by setting 8 identical rectangular grooves at equal intervals on the outer edge of a circular metal patch. The extension lines of the midlines of the two short sides of the rectangular grooves pass through the center of the circle. The sun-shaped metal patch is centered on the middle dielectric layer and does not intersect with the rectangular patch.

[0011] The four gaps between the metal ring and the equilateral right-angled triangle metal patch are all connected with variable capacitance diodes in the center along the diagonal line; the four gaps between the rectangular patch and the sun-shaped metal patch are also connected with variable capacitance diodes in the center along the diagonal line.

[0012] The second metal layer B consists of three parallel metal wire grids (feeder grids) and two fixed resistors set on each metal wire grid. The three metal wire grids are all the same length as P, and the six fixed resistors have the same resistance. Relative to the square of the intermediate dielectric layer, the middle metal wire grid is centered and parallel to one side of the square and attached to the bottom of the square. The other two metal wire grids are arranged to overlap with the parallel sides corresponding to the square relative to the middle metal wire grid.

[0013] The middle metal wire grid is connected to the sun-shaped metal patch through the central metal through-hole of the middle dielectric layer, and the two ends of the two metal wire grids on both sides are connected to the four equilateral right-angled triangle metal patches through the metal through-holes at the four corners of the middle dielectric layer.

[0014] When the structural units are arranged in a tight periodic matrix, the equilateral right-angled triangle metal patches, metal rings and squares of adjacent structural units are connected at their intersections, and the metal wire grids between adjacent structural units in the direction of the middle metal wire grid are extended and connected, and the metal wire grids on both sides of the adjacent structural units perpendicular to the direction of the middle metal wire grid are adaptively spliced ​​and connected.

[0015] Furthermore, the metal through holes at the four corner vertices of the intermediate dielectric layer are 1 / 4 of the central metal through hole (equally divided into 4 with the center of the circle as the midpoint), so that all the metal through holes arranged in the array have the same radius, which is easy to manufacture by industrial process.

[0016] Furthermore, the width of the middle metal wire grid is twice that of the other two metal wire grids, so that the overall material performance after the periodic arrangement is better.

[0017] Furthermore, based on the capacitance range of the varactor diodes, the four varactor diodes between the metal ring and the equilateral right-angled triangle metal patch are regulated to tune channel 2; or the four varactor diodes between the rectangular patch and the sun-shaped metal patch are regulated to tune channel 1; or the capacitance values ​​of all eight varactor diodes are simultaneously regulated to achieve simultaneous tuning of the bandwidths of passband 1 and passband 2.

[0018] Furthermore, the structural unit P=7 mm, and the thickness of the two metal layers is 0.035 mm.

[0019] In summary, the present invention adopts a three-layer structure, through the graphic design of the upper and lower metal layers, supplemented by 8 varactor diodes. By adjusting the capacitance of the varactor diodes, the high bandwidth range of the dual passbands can be actively tuned at the same time. Passband 1 and passband 2 both have a broadband control range. The first transmission passband has a control range of 3.8GHz to 7.3GHz, with a controllable relative bandwidth range of 63.1%; the second transmission passband has a control range of 8.5GHz to 12.0GHz, with a controllable relative bandwidth range of 34.15%; the maximum insertion loss of the two passbands is 2.5dB, and the transmittance exceeds 50%. The two transmission passbands can be adjusted simultaneously to meet more application scenarios, and are insensitive to TE and TM polarizations. Its excellent active bandwidth control performance is applicable to the multi-frequency communication needs of various agile radar antenna covers. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the overall structure of the first metal layer A in the embodiment;

[0021] Figure 2 is an enlarged schematic diagram of the first metal layer A of the structural unit of the embodiment;

[0022] Figure 3 is an enlarged schematic diagram of the second metal layer B of the structural unit of the embodiment;

[0023] Figure 4 A perspective view of a structural unit of an embodiment;

[0024] Figure 5 Schematic diagram of the transmission coefficient of the example sample under TE and TM polarization. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] An actively regulated broadband wave-transparent FSS material: the structural units are arranged in a matrix in a tight periodic manner, the structural unit is a square with a period of P, and the structural unit includes a three-layer structure of a first metal layer A, an intermediate dielectric layer, and a second metal layer B stacked in sequence from top to bottom.

[0027] In this embodiment, the enlarged schematic diagram of the first metal layer A of the structural unit is as follows: Figure 2 As shown:

[0028] The middle dielectric layer is a square dielectric with a side length of P = 7 mm (such as Figure 4 As shown in FIG, a metal through hole Q0 is provided at the center, and four 1 / 4 metal through holes (Q1, Q2, Q3, Q4) are provided at the four corners with the vertex as the center, and all the metal through holes have the same radius.

[0029] The first metal layer A comprises: an equilateral right-angled triangle metal patch, a metal ring (A10), a rectangular patch, a sun-shaped metal patch (A30) and a varactor diode.

[0030] Four equilateral right-angled triangle metal patches (A00, A01, A02, A03) are distributed on the four corners of the dielectric layer in the middle of the structural unit with their two right-angled sides adaptively aligned with one corner of the structural unit.

[0031] The metal ring (A10) is an irregular ring: the ring is constructed with the center of the square as the center, the outer ring of the ring intersects with the four sides of the square and the inner ring does not intersect, and the intersecting part of the outer ring is not counted; the corresponding ring area between the two points where one corner of the square intersects with the outer ring of the ring (that is, the ring area opposite to the equilateral right triangle metal patch) is replaced in the center with a rectangular metal strip (D1, D2, D3, D4) with the same width as the ring, and the four corners are replaced with four rectangular metal strips, and the rectangular metal strips do not touch the sides of the square or the base of the equilateral right triangle.

[0032] The rectangular patches (A20, A21, A22, A23) are arranged in a one-to-one correspondence toward the center of the circle with their long sides centrally overlapping with the inner long side of a rectangular metal strip. There are four of them in total.

[0033] The sun-shaped metal patch (A30) is formed by arranging eight identical rectangular grooves (A40, A41, A42, A43, A44, A45, A46, and A47) at equal intervals on the outer edge of a circular metal patch. The midlines of the two short sides of the rectangular grooves extend through the center of the circle. The sun-shaped metal patch is centrally arranged on the intermediate dielectric layer and does not intersect with the rectangular patch.

[0034] The four gaps between the metal ring (A10) and the equilateral right-angled triangle metal patches (A00, A01, A02, A03) are all connected diagonally and centrally with variable capacitance diodes (C00, C01, C02, C03) in a one-to-one correspondence; the four gaps between the rectangular patches (A20, A21, A22, A23) and the sun-shaped metal patch (A30) are also all connected diagonally and centrally with variable capacitance diodes (C10, C20, C30, C40) in a one-to-one correspondence.

[0035] The second metal layer B is composed of three parallel metal wire grids (B00, B01, B02) and two fixed resistors (R1, R2, R3, R4, R5, R6) arranged on each metal wire grid; relative to the square of the intermediate dielectric layer, the middle metal wire grid (B01) is centrally attached and parallel to one side of the square and is arranged below the square; the other two metal wire grids (B00, B02) are arranged to overlap with the parallel sides corresponding to the square relative to the middle metal wire grid, and their widths are both 1 / 2 of the middle metal wire grid.

[0036] In this embodiment, P = 7mm, the right-angled side of the equilateral right-angled triangular metal patch is 1.62mm long; the metal ring A10 is concentric with the structural unit, with an outer diameter of 3.6mm and an inner diameter of 3.25mm; the varactor diode is MA46H120; the rectangular patches are arranged in pairs along the two diagonals of the unit, with the long sides extending from the metal ring A10 toward the unit center, showing rotational symmetry. The rectangular patches are 0.92mm long and 1.5mm wide; the radius of the circle surrounding the sun-shaped metal patch A30 is 1.9mm, and the rectangular groove is 0.78mm long and 0.52mm wide. Both metal layers are 0.035mm thick; the intermediate dielectric layer is made of Rogers 4350B material with a dielectric constant of 3.48 and a loss tangent of 0.028, and is 1mm thick.

[0037] The array of actively regulated broadband wave-transparent FSS materials can be composed of several structural units arranged periodically in the longitudinal and transverse directions. In the first metal layer A of adjacent units, electrical continuity is formed between the triangular patches, and electrical continuity is formed between the metal rings. Figure 1 Schematic diagram of the overall structure of the first metal layer A after (8×8) matrix arrangement in this embodiment.

[0038] The metal wire grid feed lines in the second metal layer B also achieve electrical continuity between adjacent cells. Figure 3 This is a bottom view (second metal layer B) of the structural unit. Wire grid B01 is located in the center of the unit, and wire grids B00 and B02 are located on both sides of the unit. Wire grid B00 is 7 mm long and 0.5 mm wide; wire grids B01 and B02 are 7 mm long and 0.25 mm wide.

[0039] like Figure 4This is a perspective view of the overall structural unit. The intermediate dielectric layer is provided with metal vias Q0, Q1, Q2, Q3, and Q4, each with a radius of 0.2mm. Metal via Q0 is located at the center of the unit, connecting the sun-shaped metal patch A30 to the center of the wire grid B01. Q1, Q2, Q3, and Q4 are 1 / 4 metal vias, connecting the right-angled vertices of the equilateral right-angled triangle metal patch to the ends of the wire grids B00 and B02. Each wire grid is provided with a fixed resistor, R1, R2, R3, R4, R5, and R6, 1.5mm from each end. All resistors have a resistance of 39kΩ.

[0040] Under full-wave simulation, periodic boundary conditions are set in the x and y directions, RLC boundary conditions are set for the diodes, and floquet excitation mode is set in the z direction. Based on the capacitance range of the MA46H120 diode, the simulation capacitance range is selected as 0.12pF to 0.6pF. As the capacitance of the eight varactor diodes changes simultaneously, the simulated S21 curve is as follows Figure 5 As shown, the control range of passband 1 is 3.8GHz to 7.3GHz, and the controllable relative bandwidth range is 63.1%. The control range of passband 2 is 8.5GHz to 12.0GHz, and the controllable relative bandwidth range is 34.15%. The two passbands can be tuned simultaneously.

[0041] As demonstrated in the above examples, the actively regulated broadband FSS material provided by the present invention features dual-passband active regulated broadband FSS. Both passbands 1 and 2 have wideband control ranges, with a maximum insertion loss of 2.5 dB. Both transmission passbands can be simultaneously regulated, meeting a wide range of application scenarios. Its excellent actively regulated bandwidth performance is suitable for the multi-frequency communication requirements of various agile radar radomes.

Claims

1. An actively controlled broadband wave-transmitting FSS material, characterized by: The structural units are arranged in a matrix in a tight periodic manner. The structural unit is a square with a period of P. The structural unit includes a three-layer structure of a first metal layer A, an intermediate dielectric layer, and a second metal layer B stacked in sequence from top to bottom. The intermediate dielectric layer is a square dielectric with a side length of P, with a metal through hole in the center and metal through holes in the four corners centered at the vertex; The first metal layer A includes: an equilateral right triangle metal patch, a metal ring, a rectangular patch, a sun-shaped metal patch and a varactor diode; There are a total of four identical equilateral right-angled triangle metal patches, which are distributed on the four corners of the dielectric layer in the middle of the structural unit with their two right-angled sides adaptively aligned with one corner of the structural unit; The metal ring is an irregular ring: a ring is constructed with the center of the square as the center. The outer ring intersects with the four sides of the square and the inner ring does not intersect. The intersecting portion of the outer ring is not counted. The corresponding ring area between the two points where one corner of the square intersects with the outer ring of the ring is replaced with a rectangular metal strip of the same width as the ring. Four rectangular metal strips are replaced at each of the four corners of the square. The rectangular metal strips do not touch the sides of the square or the base of the equilateral right triangle. The rectangular patches are arranged in a one-to-one correspondence, with their long sides overlapping the inner long sides of the rectangular metal strips, toward the center of the circle. There are 4 in total. The sun-shaped metal patch is formed by setting 8 identical rectangular grooves at equal intervals on the outer edge of a circular metal patch. The midlines of the two short sides of the rectangular grooves extend through the center of the circle. The sun-shaped metal patch is centered on the middle dielectric layer and does not intersect with the rectangular patch. The four gaps between the metal ring and the equilateral right-angled triangle metal patch are all connected diagonally with a varactor diode in the middle; the four gaps between the rectangular patch and the sun-shaped metal patch are also connected diagonally with a varactor diode in the middle. The second metal layer B comprises three parallel metal wire grids and two fixed resistors disposed on each metal wire grid. The three metal wire grids are all the same length as P, and the six fixed resistors have the same resistance. With respect to the square of the intermediate dielectric layer, the middle metal wire grid is centered and parallel to one side of the square and attached to the bottom of the square. The other two metal wire grids are disposed relative to the middle metal wire grid and overlap with the corresponding parallel sides of the square. The middle metal wire grid is connected to the sun-shaped metal patch through the central metal through-hole of the middle dielectric layer. The two ends of the two metal wire grids on both sides are connected to the four equilateral right-angled triangle metal patches through the metal through-holes at the four corners of the middle dielectric layer. When the structural units are arranged in a tight periodic matrix, the edges of the equilateral right-angled triangle metal patches, metal rings and squares of adjacent structural units are connected, and the metal wire grids between adjacent structural units in the direction of the middle metal wire grid are extended and connected, and the metal wire grids on both sides of the adjacent structural units perpendicular to the direction of the middle metal wire grid are adaptively spliced ​​and connected.

2. The actively controlled broadband wave-transmitting FSS material according to claim 1, characterized in that: The metal through holes at the four corner vertices of the intermediate dielectric layer are 1 / 4 of the central metal through hole, so that the radius of all the metal through holes arranged in the array is the same.

3. The actively controlled broadband wave-transmitting FSS material according to claim 1, characterized in that: The width of the middle metal wire grid is twice that of the other two metal wire grids.

4. The actively controlled broadband wave-transmitting FSS material according to claim 1, characterized in that: Depending on the capacitance range of the varactor diodes, the four varactor diodes between the metal ring and the equilateral right-angled triangle metal patch are regulated to tune channel 2; or the four varactor diodes between the rectangular patch and the sun-shaped metal patch are regulated to tune channel 1; or the capacitance values ​​of all eight varactor diodes are simultaneously regulated to achieve simultaneous tuning of the bandwidths of passband 1 and passband 2.

5. The actively controlled broadband wave-transmitting FSS material according to claim 1, characterized in that: The varactor diode is MA46H120.

6. The actively controlled broadband wave-transmitting FSS material according to claim 1, characterized in that: The structural unit P is 7mm, and the thickness of the two metal layers is 0.035mm. The intermediate dielectric layer uses Rogers 4350B material with a dielectric constant of 3.48 and a loss tangent of 0.028, and has a thickness of 1mm. The right-angled side of the equilateral right-angled triangle metal patch is 1.62mm. The outer diameter of the metal ring is 3.6mm and the inner diameter is 3.25mm. The rectangular patch is 0.92mm long and 1.5mm wide. The radius of the circle to which the sun-shaped metal patch belongs is 1.9mm, and the rectangular groove is 0.78mm long and 0.52mm wide. The resistance of the six fixed resistors is 39KΩ, and they are set on each metal wire grid 1.5mm away from its two ends.

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