An electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter

Abstract

The present invention discloses an electrically controlled conversion terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter, which is composed of a high-resistance silicon layer, a polyimide layer, a common ground electrode, and a frequency control structure. The polyimide layer and the high-resistance silicon layer are superimposed, and the lower surface of the polyimide layer is in contact with the upper surface of the high-resistance silicon layer; the frequency control structure is superimposed on the upper surface of the polyimide layer, and the common ground electrode is superimposed on the lower surface of the high-resistance silicon layer. The two electrode patches of the frequency control structure are respectively connected to the positive pole of a DC regulated power supply via a switch, and the common ground electrode is directly connected to the negative pole of the DC regulated power supply. Compared with the prior art, the present invention can realize multi-frequency filtering, is suitable for different occasions, has a simple structure, and is easy to operate.

Description

Technical Field

[0001] The present invention relates to the field of terahertz technology, and in particular to an electrically controlled conversion terahertz single-frequency-dual-frequency-triple-frequency bandpass filter. Background Art

[0002] Recently, countries around the world have been gradually conducting preliminary research on 6G communication technology, which features a wider spectrum, faster transmission rates, and greater transmission capabilities. As communication frequencies increase, terahertz (THz) frequencies will become the operating frequency band for 6G communication. Filtering devices are key components in implementing THz communication technology, enabling the selection and operation of specific communication frequencies through various filter devices. Currently, THz bandpass filters mostly utilize metal structures to achieve single-frequency or multi-frequency filtering. Once fabricated, these filters can only pass THz waves of a fixed frequency or band and cannot switch between multiple THz frequencies, significantly limiting their application. Summary of the Invention

[0003] The present invention aims to solve the problem that existing terahertz bandpass filters cannot switch between multiple terahertz frequencies, and provides an electrically controlled switching terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter.

[0004] To solve the above problems, the present invention is achieved through the following technical solutions:

[0005] An electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter is described. The bandpass filter consists of a high-resistance silicon layer, a polyimide layer, a common ground electrode, and a frequency control structure. The polyimide layer and the high-resistance silicon layer are stacked, with the lower surface of the polyimide layer in contact with the upper surface of the high-resistance silicon layer. The frequency control structure is stacked on the upper surface of the polyimide layer, and the common ground electrode is stacked on the lower surface of the high-resistance silicon layer. The frequency control structure includes a surface periodic structure and an extraction structure. The surface periodic structure is located in the center of the frequency control structure and consists of multiple transmission units arranged in a regular matrix. Each transmission unit is composed of two metal patches and two graphene patches. Each metal patch is a metal patch in the shape of an "S" (S-shaped) pattern. The two metal patches are arranged in opposite directions, with the "S"-shaped openings of the two metal patches facing each other, and the transmission gap formed between them is S-shaped. Each graphene patch is a long strip of graphene material. The two graphene patches are respectively arranged at the "S"-shaped openings of the metal patches, closing the "S"-shaped openings of the metal patches. The extraction structure is located on the opposite side of the surface periodic structure and consists of two electrode patches. Each electrode patch is a comb-shaped metal patch. The two electrode patches are connected to the same metal patch of all transmission units. The common ground electrode is a closed ring-shaped metal patch. The two electrode patches of the frequency control structure are respectively connected to the positive electrode of the DC regulated power supply via a switch, and the common ground electrode is directly connected to the negative electrode of the DC regulated power supply.

[0006] In the above solution, the center of the common ground electrode is perpendicular to the center of the surface periodic structure.

[0007] In the above solution, the area covered by the surface periodic structure is larger than the area of ​​the terahertz beam spot irradiated on the bandpass filter, and the area covered by the inner ring of the common ground electrode is larger than the area of ​​the terahertz beam spot irradiated on the bandpass filter.

[0008] In the above scheme, the area covered by the surface periodic structure is 1.5 to 2.5 times the area of ​​the terahertz beam spot irradiated on the bandpass filter, and the area covered by the inner ring of the common ground electrode is 1.5 to 2.5 times the area of ​​the terahertz beam spot irradiated on the bandpass filter.

[0009] In the above scheme, each metal patch is composed of five long, sheet-like metal strips connected together; the first metal strip, the third metal strip, and the fifth metal strip all extend horizontally and are parallel to each other; the second metal strip and the fourth metal strip all extend longitudinally and are parallel to each other; the head end of the first metal strip is located at one side edge of the transmission unit, the tail end of the first metal strip is connected to the head end of the second metal strip, the tail end of the second metal strip is connected to the head end of the third metal strip, the tail end of the third metal strip is connected to the head end of the fourth metal strip, the tail end of the fourth metal strip is connected to the head end of the fifth metal strip, and the tail end of the fifth metal strip is located at the other side edge of the transmission unit; the gap between the second metal strip and the fourth metal strip forms the X-shaped opening width of the metal patch.

[0010] In the above solution, the widths of the S-shaped openings of the two metal patches of the transmission unit are different.

[0011] In the above solution, the graphene patch is arranged at the entrance of the X-shaped opening of the metal patch, and its two ends are respectively connected to the end of the first metal strip and the beginning of the fifth metal strip.

[0012] In the above solution, the common ground electrode is a circular ring.

[0013] In the above scheme, the voltage of the DC regulated power supply is 5V~24V.

[0014] Compared with the prior art, the present invention can realize multi-frequency filtering, is suitable for different occasions, has a simple structure and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the three-dimensional structure of an electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter;

[0016] Figure 2 for Figure 1 A top view of

[0017] Figure 3 for Figure 2 A schematic diagram of the structure of a transmission unit;

[0018] Figure 4 for Figure 1 Bottom view of

[0019] Figure 5 Schematic diagram of a curve showing the variation of terahertz wave transmittance with frequency when the electrodes are powered on and powered off according to a preferred embodiment of the present invention.

[0020] Numbers in the figure: 1 common ground electrode; 2 high-resistance silicon layer; 3 polyimide layer; 4 frequency control structure; 41 metal patch; 42 graphene patch; 43 electrode patch. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific examples.

[0022] See also Figure 1 An electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter comprises a common ground electrode 1, a high-resistance silicon layer 2, a polyimide layer 3, and a frequency control structure 4. The common ground electrode 1 is superimposed on the lower surface of the high-resistance silicon layer 2. The high-resistance silicon layer 2 and the polyimide layer 3 are superimposed, with the upper surface of the high-resistance silicon layer 2 in contact with the lower surface of the polyimide layer 3. The frequency control structure 4 is superimposed on the upper surface of the polyimide layer 3.

[0023] In the present invention, the high-resistance silicon layer 2 and the polyimide layer 3 can be circular, square, or polygonal in shape, as long as they can accommodate the common ground electrode 1 and the frequency control structure 4. The polyimide layer 3 is a sheet made of polyimide material, and the high-resistance silicon layer 2 is a sheet made of high-resistance silicon material. In a preferred embodiment of the present invention, both the high-resistance silicon layer 2 and the polyimide layer 3 are rectangular. The thickness of the high-resistance silicon layer 2 is 0.5 mm, and the thickness of the polyimide layer 3 is 28 μm.

[0024] See also Figure 2 The frequency control structure 4 comprises a surface periodic structure and an extraction structure. The surface periodic structure is located in the middle of the frequency control structure 4 and is composed of multiple transmission units arranged in a regular matrix. The extraction structure is located on the outer side of the surface periodic structure and is composed of two electrode patches 43.

[0025] Each transmission unit of the surface periodic structure is composed of two metal patches 41 and two graphene patches 42. Figure 3 In a preferred embodiment of the present invention, the thickness of the metal patch 41 is 0.2-0.8 μm, and the thickness of the graphene patch 42 is 0.3 nm-1 nm.

[0026] Each metal patch 41 is an "X"-shaped sheet made of metal material. Each metal patch 41 is made up of five long, sheet-shaped metal strips connected together. The widths of these five metal strips can be equal or unequal, and the transmission peak intensity of the device can be changed by adjusting the width of the metal strips. The first metal strip, the third metal strip, and the fifth metal strip all extend horizontally and are parallel to each other. The second metal strip and the fourth metal strip all extend longitudinally and are parallel to each other. The head end of the first metal strip is located at one side edge of the transmission unit, the end of the first metal strip is connected to the head end of the second metal strip, the end of the second metal strip is connected to the head end of the third metal strip, the end of the third metal strip is connected to the head end of the fourth metal strip, the end of the fourth metal strip is connected to the head end of the fifth metal strip, and the end of the fifth metal strip is located at the other side edge of the transmission unit. The gap between the second metal strip and the fourth metal strip forms the "X"-shaped opening of the metal patch 41.

[0027] In each transmission unit, the two metal patches 41 are arranged facing away from each other, meaning that the "X"-shaped openings of the two metal patches 41 face opposite directions, and the transmission gap formed between them is S-shaped. At this point, the third metal strip of the first metal patch is parallel to and close to the fifth metal strip of the second metal patch, the fourth metal strip of the first metal patch is parallel to and close to the fourth metal strip of the second metal patch, and the fifth metal strip of the first metal patch is parallel to and close to the third metal strip of the second metal patch. The "X"-shaped opening of the first metal patch faces upward, while the "X"-shaped opening of the second metal patch faces downward. The fifth metal strip of the first metal patch is longer than the third metal strip of the second metal patch, and the fifth metal strip of the second metal patch is longer than the third metal strip of the first metal patch.

[0028] In each transmission unit, the two metal patches 41 have different "X"-shaped opening widths. Since the spacing between the metal patches 41 or metal strips is inversely proportional to the transmission frequency of the bandpass filter (the wider the spacing, the lower the transmission frequency, and the narrower the spacing, the higher the transmission frequency), the metal patches 41 with larger "X"-shaped opening widths are defined as low-frequency metal patches, while the metal patches 41 with smaller "X"-shaped opening widths are defined as high-frequency metal patches. The "X"-shaped opening width of the low-frequency metal patch, i.e., the lateral spacing between the second and fourth metal strips of the low-frequency metal patch, corresponds to the low-frequency transmission frequency of the bandpass filter. The "X"-shaped opening width of the high-frequency metal patch, i.e., the lateral spacing between the second and fourth metal strips of the high-frequency metal patch, corresponds to the high-frequency transmission frequency of the bandpass filter. The longitudinal spacing between the third metal strip of the low-frequency metal patch and the fifth metal strip of the high-frequency metal patch is equal to the longitudinal spacing between the fifth metal strip of the low-frequency metal patch and the third metal strip of the high-frequency metal patch, which corresponds to the mid-frequency transmission frequency of the bandpass filter. In a preferred embodiment of the present invention, the width of the "X"-shaped opening of the low-frequency metal patch is 56 μm, corresponding to a high-frequency transmission frequency of 0.8 THz. The width of the "X"-shaped opening of the high-frequency metal patch is 6 μm, corresponding to a high-frequency transmission frequency of 1.58 THz. The longitudinal spacing between the third metal strip of the low-frequency metal patch and the fifth metal strip of the high-frequency metal patch is equal to the longitudinal spacing between the fifth metal strip of the low-frequency metal patch and the third metal strip of the high-frequency metal patch, which is 14 μm, corresponding to a medium-frequency transmission frequency of 1.14 THz.

[0029] Each graphene patch 42 is a long, strip-shaped sheet made of graphene material. The two graphene patches 42 are respectively arranged at the two "X"-shaped openings of the metal patch 41, and the "X"-shaped openings of the metal patch 41 are closed, that is, one end of the graphene patch 42 is connected to the second metal strip of the metal patch 41, and the other end of the graphene patch 42 is connected to the fourth metal strip of the metal patch 41. In this way, the split ring resonator composed of the second, third, and fourth metal strips of the metal patch 41 can be equivalent to an LC resonant circuit. In the longitudinal direction, the graphene patch 42 is parallel to the third metal strip of the metal patch 41. It can be arranged at a position close to the third metal strip of the metal patch 41 or at a position away from the third metal strip of the metal patch 41. In a preferred embodiment of the present invention, the graphene patch 42 is arranged at the entrance of the "X"-shaped opening of the metal patch 41, that is, the two ends of the graphene patch 42 are respectively connected to the end of the first metal strip and the beginning of the fifth metal strip. After the power is turned on, the Fermi energy of graphene is adjusted to increase the carrier concentration. At this time, the LC resonant circuit structure can be approximately equivalent to a resistance circuit, that is, after the voltage is applied to the device, the current flows directly from the first metal strip of the metal patch 41 through the graphene patch 42 to the fifth metal strip of the metal patch 41, resulting in a significant decrease in the transmission peak intensity of the low-frequency transmission frequency and the high-frequency transmission frequency, thereby realizing the selective regulation of frequency.

[0030] The two electrode patches 43 of the lead-out structure are both comb-shaped sheets made of metal. They are connected to the same metal patch 41 of all transmission units. One electrode patch 43 (the low-frequency electrode patch 43) is connected to the low-frequency metal patch of all transmission units, and the other electrode patch 43 (the high-frequency electrode patch 43) is connected to the high-frequency metal patch of all transmission units.

[0031] See also Figure 4The common ground electrode 1 is a closed ring-shaped sheet made of metal material. The common ground electrode 1 can be in the shape of a circular ring, a square ring, a polygonal ring, etc. In a preferred embodiment of the present invention, the thickness of the common ground electrode 1 is 0.2 to 0.8 μm and the common ground electrode 1 is a circular ring. In the present invention, the center of the common ground electrode 1 and the center of the surface periodic structure can be slightly offset in the vertical direction. However, in order to achieve uniform electrification of the graphene, in a preferred embodiment of the present invention, the center of the common ground electrode 1 is perpendicular to the center of the surface periodic structure, that is, the perpendicular bisector of the common ground electrode 1 coincides with the perpendicular bisector of the entire surface periodic structure. The terahertz wave is incident directly from directly above the bandpass filter, that is, directly above the surface periodic structure. In order to allow the terahertz beam on the band-pass filter to pass through unobstructed, the area covered by the surface periodic structure, that is, all the transmission units, is larger than the area of ​​the terahertz beam spot irradiated on the band-pass filter, which is 1.5 to 2.5 times the area of ​​the terahertz beam spot; the area covered by the inner ring of the common ground electrode 1 is larger than the area of ​​the terahertz beam spot irradiated on the band-pass filter, which is 1.5 to 2.5 times the area of ​​the terahertz beam spot.

[0032] When in use, the two electrode patches 43 of the surface periodic structure are each connected to the positive pole of the DC regulated power supply via a switch, and the common ground electrode 1 is directly connected to the negative pole of the DC regulated power supply. In a preferred embodiment of the present invention, the voltage of the DC regulated power supply is 5V to 24V. When the switch of a certain electrode patch 43 is disconnected, the same metal patch 41 of all transmission units connected thereto is powered off, and the graphene patch 42 at the X-shaped opening of the metal patch 41 exhibits a low Fermi energy level. When the switch of a certain electrode patch 43 is closed, the same metal patch 41 of all transmission units connected thereto is powered on, and the graphene patch 42 at the X-shaped opening of the metal patch 41 exhibits a high Fermi energy level. Based on this principle, the bandpass filter of the present invention has the following four working states, such as Figure 5 As shown:

[0033] When the low-frequency electrode patch 43 and the high-frequency electrode patch 43 are both not energized, corresponding to the binary code 00, the low-frequency transmission frequency, the intermediate-frequency transmission frequency, and the high-frequency transmission frequency of the band-pass filter are all high transmission peaks. At this time, the band-pass filter is a three-channel band-pass filter.

[0034] When the low-frequency electrode patch 43 is powered on and the high-frequency electrode patch 43 is not powered on, corresponding to the binary code 01, the intermediate frequency transmission frequency and the high frequency transmission frequency of the band-pass filter are both high transmission peaks, and the low frequency transmission frequency is a low transmission peak. At this time, the band-pass filter is a dual-channel band-pass filter;

[0035] When the low-frequency electrode patch 43 is not energized and the high-frequency electrode patch 43 is energized, corresponding to the binary code 10, the intermediate frequency transmission frequency and the low-frequency transmission frequency of the band-pass filter are both high transmission peaks, and the high-frequency transmission frequency is a low transmission peak. At this time, the band-pass filter is a dual-channel band-pass filter;

[0036] When both the low-frequency electrode patch 43 and the high-frequency electrode patch 43 are energized, corresponding to the binary code 11, the low-frequency transmission frequency and the high-frequency transmission frequency of the bandpass filter are both low transmission peaks, and the intermediate-frequency transmission frequency is a high transmission peak. At this time, the bandpass filter is a single-channel bandpass filter.

[0037] It should be noted that although the embodiments of the present invention described above are illustrative, they are not intended to limit the present invention. Therefore, the present invention is not limited to the above-mentioned specific embodiments. Without departing from the principles of the present invention, any other embodiments obtained by those skilled in the art under the guidance of the present invention are deemed to be within the protection of the present invention.

Claims

1. An electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter, characterized in that: The bandpass filter is composed of a common ground electrode (1), a high-resistance silicon layer (2), a polyimide layer (3), and a frequency control structure (4); the common ground electrode (1) is stacked on the lower surface of the high-resistance silicon layer (2), the high-resistance silicon layer (2) and the polyimide layer (3) are stacked, and the upper surface of the high-resistance silicon layer (2) is in contact with the lower surface of the polyimide layer (3); the frequency control structure (4) is stacked on the upper surface of the polyimide layer (3); The frequency control structure (4) includes a surface periodic structure and a lead-out structure; The surface periodic structure is located in the middle of the frequency control structure (4) and is composed of a plurality of transmission units arranged in a regular matrix; each transmission unit is composed of two metal patches (41) and two graphene patches (42); Each metal patch (41) is an "S"-shaped sheet made of metal material; the two metal patches (41) are arranged back to back, i.e., the "S"-shaped openings of the two metal patches (41) are oriented in opposite directions, and a transmission gap formed between the two is S-shaped; the "S"-shaped openings of the two metal patches (41) have different widths, and the metal patch (41) with a larger "S"-shaped opening width is defined as a low-frequency metal patch, and the metal patch (41) with a smaller "S"-shaped opening width is defined as a high-frequency metal patch; Each graphene patch (42) is a long strip of graphene material; the two graphene patches (42) are respectively arranged at the "J"-shaped openings of the two metal patches (41), and the "J"-shaped openings of the metal patches (41) are closed; The lead-out structure is located on the relatively outer side of the surface periodic structure and is composed of two electrode patches (43); each electrode patch (43) is a comb-shaped sheet made of metal material; the two electrode patches (43) are respectively connected to the same metal patch (41) of all transmission units, that is, one electrode patch (43), i.e., a low-frequency electrode patch, is connected to the low-frequency metal patches of all transmission units, and the other electrode patch (43), i.e., a high-frequency electrode patch, is connected to the high-frequency metal patches of all transmission units; The common ground electrode (1) is a closed ring-shaped sheet made of metal material; The two electrode patches (43) of the frequency control structure (4) are respectively connected to the positive electrode of the DC regulated power supply via a switch, and the common ground electrode (1) is directly connected to the negative electrode of the DC regulated power supply; When both the low-frequency electrode patch and the high-frequency electrode patch are not energized, corresponding to the binary code 00, the low-frequency transmission frequency, the intermediate-frequency transmission frequency, and the high-frequency transmission frequency of the band-pass filter are all high transmission peaks. At this time, the band-pass filter is a three-channel band-pass filter. When the low-frequency electrode patch is powered on and the high-frequency electrode patch is not powered on, corresponding to the binary code 01, the intermediate frequency transmission frequency and the high frequency transmission frequency of the band-pass filter are both high transmission peaks, and the low frequency transmission frequency is a low transmission peak. At this time, the band-pass filter is a dual-channel band-pass filter; When the low-frequency electrode patch is not powered and the high-frequency electrode patch is powered, corresponding to the binary code 10, the intermediate frequency transmission frequency and the low-frequency transmission frequency of the band-pass filter are both high transmission peaks, and the high-frequency transmission frequency is a low transmission peak. At this time, the band-pass filter is a dual-channel band-pass filter; When both the low-frequency electrode patch and the high-frequency electrode patch are energized, corresponding to the binary code 11, the low-frequency transmission frequency and the high-frequency transmission frequency of the band-pass filter are both low transmission peaks, and the intermediate-frequency transmission frequency is a high transmission peak. At this time, the band-pass filter is a single-channel band-pass filter.

2. The electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter according to claim 1, wherein: The center of the common ground electrode (1) is perpendicular to the center of the surface periodic structure.

3. The electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter according to claim 1 or 2, characterized in that: The area covered by the surface periodic structure is larger than the area of ​​the terahertz beam spot irradiated on the bandpass filter, and the area covered by the inner ring of the common ground electrode (1) is larger than the area of ​​the terahertz beam spot irradiated on the bandpass filter.

4. The electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter according to claim 3, wherein: The area covered by the surface periodic structure is 1.5 to 2.5 times the area of ​​the terahertz beam spot irradiated on the bandpass filter, and the area covered by the inner ring of the common ground electrode (1) is 1.5 to 2.5 times the area of ​​the terahertz beam spot irradiated on the bandpass filter.

5. The electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter according to claim 1, wherein: Each metal patch (41) is formed by connecting five long sheet-shaped metal strips; the first metal strip, the third metal strip and the fifth metal strip are all extended horizontally and parallel to each other; the second metal strip and the fourth metal strip are all extended longitudinally and parallel to each other; the head end of the first metal strip is located at one side edge of the transmission unit, the end of the first metal strip is connected to the head end of the second metal strip, the end of the second metal strip is connected to the head end of the third metal strip, the end of the third metal strip is connected to the head end of the fourth metal strip, the end of the fourth metal strip is connected to the head end of the fifth metal strip, and the end of the fifth metal strip is located at the other side edge of the transmission unit; the gap between the second metal strip and the fourth metal strip forms the width of the "X"-shaped opening of the metal patch (41).

6. The electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter according to claim 1 or 5, characterized in that: The widths of the X-shaped openings of the two metal patches (41) of the transmission unit are different.

7. The electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter according to claim 1 or 5, characterized in that: The graphene patch (42) is arranged at the entrance of the X-shaped opening of the metal patch (41), and its two ends are respectively connected to the end of the first metal strip and the beginning of the fifth metal strip.

8. The electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter according to claim 1, wherein: The common ground electrode (1) is a circular ring.

9. The electrically controlled terahertz single-frequency, dual-frequency, and triple-frequency bandpass filter according to claim 1, wherein: The voltage of the DC regulated power supply is 5V~24V.

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