CN114447548A - Terahertz wave tunable waveguide type narrow-band filter - Google Patents
Terahertz wave tunable waveguide type narrow-band filter Download PDFInfo
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- CN114447548A CN114447548A CN202210193806.1A CN202210193806A CN114447548A CN 114447548 A CN114447548 A CN 114447548A CN 202210193806 A CN202210193806 A CN 202210193806A CN 114447548 A CN114447548 A CN 114447548A
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- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
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- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/207—Hollow waveguide filters
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Abstract
The invention provides a terahertz wave tunable waveguide type narrow-band filter and a manufacturing method thereof. The invention has the advantages of simple structure, small size, low cost, easy integration and the like; the Q value is high, the insertion loss is small, and the transmission loss is small; the tuning of the output center frequency of the filter can be realized by adjusting the transverse position of the filter; the filter bandwidth and the transmissivity of the filter can be changed by changing the number of the waveguide periods, the distance between the upper flat plate and the lower flat plate and the depth of the groove.
Description
Technical Field
The invention belongs to the technical field of micro-nano optical devices and optical communication, and particularly relates to a terahertz wave tunable waveguide type narrow-band filter.
Background
The terahertz wave is an electromagnetic wave with the frequency range of 0.1 THz-10 THz and the wavelength between microwave and far infrared. The terahertz wave is a special area for transition from electronics to photonics, has many unique advantages, and has wide research value and application prospect in the fields of broadband communication, nondestructive detection, safety inspection and the like. In practical applications, the terahertz system is limited by environmental noise and application requirements. In order to improve the performance of the terahertz system and promote the application of terahertz waves in the communication field, unnecessary frequency ranges and noises need to be filtered, so that functional devices such as terahertz wave tunable narrow-band filters have important research significance and value.
At present, terahertz filters are mainly based on photonic crystal structure type, quantum well structure type, waveguide type terahertz filters and the like, and certain achievements are obtained in domestic and foreign research. In 2010, Rajin Mendis et al studied slab waveguide based low-pass, high-pass, band-pass and band-stop terahertz filters. In 2020, Kehui Jia, Lina Fan and Zhaoliang Cao propose a terahertz narrow-band filter based on fluctuation parallel plate waveguide forbidden band modulation, the bandwidth is 5.8GHz, the transmittance can reach 99.8%, and liquid crystal is added on the basis to realize tunable filter frequency. In 2011, Zhao Dongmei, Zhouqingli, Li Lei et al propose a terahertz tunable narrow-band filter with a sub-wavelength array structure based on FDTD simulation, so that the filtering frequency can be adjusted within the range of 2.5 THz-20 THz, and the minimum bandwidth reaches 0.04 THz. In 2016, Chen He Ming, Teng Chen and Wen et al put forward a terahertz filter using garnet type ferrite magnetic material, and the THz wave is filtered by changing the magnitude of an external magnetic field, so that low-loss narrow-band filtering is realized, and the insertion loss of the terahertz filter is 0.0997 dB. Chinese patent application No. 201710585750.3 discloses a narrow band frequency-selecting and frequency-tuning terahertz narrow band filter and a method thereof, which proposes a narrow band frequency-selecting and frequency-tuning terahertz narrow band filter, and meets the requirements of realizing a narrow band filter within several GHz bandwidths within a terahertz frequency band. The chinese patent application No. 201721274742.9 proposes a tunable terahertz narrow-band filter, which realizes a voltage-tunable terahertz narrow-band filter, and exhibits excellent transmission efficiency. Compared with the terahertz filter, the waveguide terahertz filter is simple in structure, simple in manufacturing process and easy to integrate.
At present, the terahertz wave filter structure researched at home and abroad is mainly based on structures such as metamaterials and photonic crystals, and the terahertz wave filter has the disadvantages of complex structure, high processing technology requirement, difficulty in manufacturing and great influence on the application of the terahertz wave filter. Meanwhile, the non-waveguide filters are not beneficial to integration, the tuning process is complex, and the realization difficulty is high. The tunable waveguide type narrow-band filter provided by the invention has the advantages of simple structure, easiness in manufacturing, tunable wave band, easiness in integration and the like, and can meet the application requirements of terahertz waves, especially the development requirements in the technical field of future 6G communication.
Disclosure of Invention
In order to solve the above problems, the present inventors have conducted many designs and studies to provide a terahertz wave tunable waveguide type narrow band filter which is low in transmission loss, low in insertion loss, and easy to integrate.
According to the technical scheme of the invention, the terahertz wave tunable waveguide type narrow-band filter comprises a cavity with a rectangular structure, wherein the upper surface and the lower surface of the cavity are low-loss metal surfaces with periodic groove structures, a wedge-shaped protruding area is arranged in the middle of the cavity, and two side walls are planes. The number of waveguide cycles, the distance between the upper metal flat plate and the lower metal flat plate, the inclination angle of the symmetrical structure and the cycle size in the terahertz tunable waveguide type narrow-band filter can be changed according to practical application scenes.
Further, the filtering bandwidth and the transmissivity of the filter are changed by changing the number and the size of the wave guide periods; the center frequency of the filter is changed by adjusting the transverse position of the filter, so that tunable narrow-band filtering of the terahertz signal is realized. The filter line width is 0.001THz, and the transmittance is higher than 97%.
Preferably, the upper surface and the lower surface of the cavity of the rectangular structure are both periodic groove structures which are provided with wedge-shaped protrusions and are symmetrical about the center and have a certain inclination angle, the parameters of the periodic structures can be designed according to the actual working frequency band, and the inclination angle of the wedge-shaped protrusions can be selected according to the tuning precision. Wherein the inclination angle of the wedge-shaped bulge is 2-5 degrees. The material of the upper surface and the lower surface of the cavity of the rectangular structure is a low-loss metal material of a terahertz frequency band, and the cavity of the rectangular structure is formed by photoetching on a non-metal material and then coating a metal film.
More preferably, the non-metallic material is acrylic, glass or silicon wafer; the metal is gold or silver, and the thickness of the plated film is more than 100 nm.
Compared with the prior art, the terahertz wave tunable waveguide type narrow-band filter has the following technical advantages:
1. the invention has the advantages of simple structure, small size, low cost, easy integration and the like; the Q value is high, the insertion loss is small, and the transmission loss is small; the tuning of the output center frequency of the filter can be realized by adjusting the transverse position of the filter; the filter bandwidth and the transmissivity of the filter can be changed by changing the number of the waveguide periods, the distance between the upper flat plate and the lower flat plate and the depth of the groove.
2. Narrow line width, small volume, simple structure, simple manufacturing process and easy integration; the filter has narrow frequency band, the filter line width can reach 0.001THz, and the transmissivity is higher than 97%.
3. The filter bandwidth and the transmissivity of the filter can be changed through the number of waveguide periods, the distance between the parallel flat plate waveguides and the depth of the groove.
4. The filter structure is a symmetrical structure, is available in two directions and has no direction requirement; the transmission loss is small and the insertion loss is small.
5. Compared with the existing terahertz filter, the terahertz filter has the advantages of easily available filter materials, narrow frequency band, high transmissivity, high Q value and easily adjustable center frequency.
Drawings
Fig. 1 is a schematic structural view of a terahertz wave tunable waveguide type narrow band filter according to the present invention;
fig. 2 is a top view of upper and lower flat plate surfaces employed in the terahertz wave tunable waveguide-type narrow band filter in fig. 1;
fig. 3 is a spectral diagram of a terahertz wave tunable waveguide type narrow-band filter.
The reference numbers in the drawings are as follows: the terahertz wave filter comprises a terahertz wave incidence direction 1, a terahertz wave emission direction 2, a micrometer 3, filter periodic structure defect lengths d and b, wherein the filter periodic structure period length and the groove length are a and c respectively.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Additionally, the scope of the present invention should not be limited to the particular structures or components or the particular parameters described below.
The terahertz wave tunable waveguide type narrow-band filter provided by the invention is a terahertz functional device, and can be used for filtering interference signals in a terahertz system so as to improve the performance of the terahertz system. The terahertz wave tunable waveguide type narrow-band filter provided by the invention can limit terahertz waves to be transmitted in a certain area, and has the advantages of small transmission loss and small insertion loss.
Furthermore, the terahertz tunable waveguide type narrow-band filter comprises a cavity with a rectangular structure, wherein the upper surface and the lower surface of the cavity are low-loss metal surfaces with periodic groove structures, a wedge-shaped protruding area is arranged in the middle of the cavity, and two side walls are planes; the number of wave guide periods, the distance between the upper metal flat plate and the lower metal flat plate, the inclination angle of the symmetrical structure and the period can be changed according to the practical application scene. The filtering bandwidth and the transmissivity of the filter are changed by changing the number and the size of the wave guide periods; the center frequency of the filter is changed by adjusting the transverse position of the filter, so that tunable narrow-band filtering of the terahertz signal is realized, the filtering line width can reach 0.001THz, and the transmittance is higher than 97%. The filter has the advantages of simple structure, small size, low cost, easy integration, narrow frequency band, low loss (insertion and transmission) and the like.
In an embodiment of the present invention, as shown in fig. 1, a terahertz wave tunable waveguide-type narrowband filter includes a cavity having a rectangular structure, the upper surface and the lower surface of the cavity are low-loss metal surfaces having a periodic groove structure, a wedge-shaped protrusion region is included in the middle of the upper surface of the cavity, two side walls are planes, and the center frequency of the terahertz wave tunable waveguide-type narrowband filter can be changed by adjusting the lateral position of the terahertz wave tunable waveguide-type narrowband filter, so as to implement tunable narrowband filtering of a terahertz signal. In fig. 1, a cavity filter with a rectangular structure is mounted on a micrometer support which can be laterally adjusted, and the tuning of the output center frequency of the terahertz wave tunable waveguide type narrow-band filter is realized by adjusting the lateral position of the terahertz wave tunable waveguide type narrow-band filter, so that the tunable narrow-band filtering of terahertz signals is realized; further, the terahertz wave is incident from an incident point 1 on the left side of the terahertz wave tunable waveguide type narrow band and is emitted from an emitting point 2 on the right side of the terahertz wave tunable waveguide type narrow band filter through the terahertz wave tunable waveguide type narrow band filter. Fig. 3 shows frequency spectrums of different positions of the terahertz wave tunable waveguide-type narrow-band filter, and the protruding lengths of the periodic structures of the corresponding filters are 600, 800, 1000, 1200 and 1400 micrometers in sequence.
The upper surface and the lower surface of the cavity of the rectangular structure are both periodic groove structures which are provided with wedge-shaped bulges and are symmetrical about the center and have certain inclination angles, the parameters of the periodic structures can be designed according to the actual working frequency band, and the inclination angles of the wedge-shaped bulges can be selected according to the tuning precision, and are usually 2-5 degrees. The filtering bandwidth and the transmissivity of the terahertz wave tunable waveguide type narrow-band filter can be changed by changing the number of waveguide periods and the depth of the groove of the periodic structure, and the terahertz wave tunable waveguide type narrow-band filter can be selected according to actual needs. In a preferred embodiment, the material of the upper surface and the lower surface of the cavity of the rectangular structure is a low-loss metal material in the terahertz frequency band, and the structure of the cavity can be realized by performing photolithography processing on a non-metal material (such as acrylic, glass, a silicon wafer, and the like) and then performing metal (gold, silver, and the like) plating (preferably, the film thickness is greater than 100 nm). The structures of the upper surface and the lower surface can be directly processed on the metal surface by photoetching, and the materials are low-loss metal materials of terahertz frequency band, such as gold, silver, aluminum alloy, stainless steel and the like. The cavity with the rectangular structure can be realized by packaging according to design parameters after the upper surface and the lower surface are manufactured.
In another embodiment, the cross sections of the periodic groove structures on the upper surface and the lower surface of the cavity of the rectangular structure can be in the shapes of rectangle, trapezoid, sawtooth, sine and cosine functions and the like, and can be selected according to actual requirements and processing means.
As shown in fig. 2, the width of the waveguide wedge-shaped protrusion on the upper and lower flat plate surfaces of the terahertz wave tunable waveguide-type narrow band filter is adjustable by adjusting the lateral position of the filter, and the range is d micrometers (μm) to b micrometers (μm), where a represents the period length of the periodic structure of the filter, and c represents the width of the lithography groove. The shape of the periodic grooves on the upper surface and the lower surface of the cavity can be selected from the shapes of rectangle, trapezoid, sawtooth, sine and cosine and the like, and can be selected according to actual requirements. The center frequency of the filter can be changed by adjusting the transverse position of the filter, so that tunable narrow-band filtering of the terahertz signal is realized.
Further, the groove structures on the upper and lower surfaces of the waveguide are fabricated by directly performing photolithography on the surface of Al (aluminum) alloy, and the photolithographic surface material may be other low-loss metal materials in the terahertz frequency band, such as gold, silver, aluminum alloy, stainless steel, and the like. The shape of the cavity surface periodic structure can be selected according to actual requirements, such as rectangle, sawtooth, sine and cosine and the like. The number of waveguide cycles, the distance between the parallel plate waveguides, the inclination angle of the symmetrical structure and the cycle size are variable, and the filtering bandwidth and the transmissivity of the filter can be changed by changing the number of the waveguide cycles, the distance between the parallel plate waveguides and the cycle size.
Furthermore, in the upper and lower surface plates shown in fig. 2, the number of cycles on both sides of the wedge shape of the waveguide structure is 10, the spacing between the parallel plate waveguides is 250 meters (m), and the cycle a is 200 meters (m); the periodic structure with the variable wedge widths on the upper surface and the lower surface of the cavity is a groove structure which is symmetrical about the center and has a certain inclination angle, the parameters of the periodic structure can be designed according to the actual working frequency band, and the size of the inclination angle can be selected according to the tuning precision. The inclination angle of the waveguide is 2 degrees around the central symmetry, and the adjustable range of the wedge-shaped projection width of the filter is 320 meters (m) to 2000 meters (m).
Fig. 3 is a frequency spectrum diagram of a terahertz wave tunable waveguide-type narrow-band filter, and it can be seen from fig. 3 that transmission frequency spectrum diagrams of different output frequencies can be obtained by adjusting the transverse positions of waveguides according to the width order of the wedge-shaped protrusions. The center frequency of the narrow-band filter moves to low frequency along with the increase of the width of the wedge-shaped bulge, and tunable narrow-band filtering of the terahertz signal can be achieved.
The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are also within the scope of the present invention. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
Claims (10)
1. A terahertz wave tunable waveguide type narrow-band filter is characterized by comprising a cavity with a rectangular structure, wherein the upper surface and the lower surface of the cavity are low-loss metal surfaces with periodic groove structures, a wedge-shaped protruding area is arranged in the middle of the cavity, and two side walls are planes.
2. The terahertz wave tunable waveguide-type narrowband filter according to claim 1, wherein the number of waveguide periods, the distance between the upper metal plate and the lower metal plate, the inclination angle of the symmetric structure, and the period size in the terahertz wave tunable waveguide-type narrowband filter can be changed according to practical application scenarios.
3. The terahertz wave tunable waveguide-type narrow band filter according to claim 2, wherein a filtering bandwidth and a transmittance of the filter are changed by changing the number of waveguide cycles and the size of the cycles; the center frequency of the filter is changed by adjusting the transverse position of the filter, so that tunable narrow-band filtering of the terahertz signal is realized.
4. The terahertz wave tunable waveguide-type narrow band filter according to claim 2, wherein a filter line width is 0.001THz, and a transmittance is higher than 97%.
5. The terahertz wave tunable waveguide-type narrow band filter according to claim 2, wherein the upper surface and the lower surface of the cavity of the rectangular structure are periodic groove structures which are provided with wedge-shaped protrusions and are symmetrical with respect to the center and have a certain inclination angle, the parameters of the periodic structures can be designed according to an actual working frequency band, and the inclination angle of the wedge-shaped protrusions can be selected according to tuning accuracy.
6. The terahertz wave tunable waveguide-type narrow band filter according to claim 5, wherein an inclination angle of the wedge-shaped projection is 2 to 5 degrees.
7. The terahertz wave tunable waveguide-type narrow band filter according to claim 2, wherein the material of the upper and lower surfaces of the cavity of the rectangular structure is a low-loss metal material in the terahertz frequency band, and the cavity of the rectangular structure is formed by performing photolithography processing on a non-metal material and then by metal plating.
8. The terahertz wave tunable waveguide-type narrow band filter according to claim 7, wherein the non-metallic material is acrylic, glass, or a silicon wafer.
9. The terahertz wave tunable waveguide-type narrow band filter according to claim 7, wherein the metal is gold or silver.
10. The terahertz wave tunable waveguide-type narrow band filter according to claim 7, wherein a film thickness of the plating film is greater than 100 nm.
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| CN202210193806.1A CN114447548A (en) | 2022-03-01 | 2022-03-01 | Terahertz wave tunable waveguide type narrow-band filter |
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| CN202210193806.1A CN114447548A (en) | 2022-03-01 | 2022-03-01 | Terahertz wave tunable waveguide type narrow-band filter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114824705A (en) * | 2022-05-24 | 2022-07-29 | 桂林电子科技大学 | Terahertz waveguide type mode selector based on multimode resonance |
| CN115020946A (en) * | 2022-05-25 | 2022-09-06 | 桂林电子科技大学 | Band-stop filter with S-shaped metal structure and cut opening |
| CN115332743A (en) * | 2022-07-28 | 2022-11-11 | 西安空间无线电技术研究所 | Terahertz reconfigurable filter with planar mask structure and preparation method |
-
2022
- 2022-03-01 CN CN202210193806.1A patent/CN114447548A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114824705A (en) * | 2022-05-24 | 2022-07-29 | 桂林电子科技大学 | Terahertz waveguide type mode selector based on multimode resonance |
| CN115020946A (en) * | 2022-05-25 | 2022-09-06 | 桂林电子科技大学 | Band-stop filter with S-shaped metal structure and cut opening |
| CN115020946B (en) * | 2022-05-25 | 2023-09-29 | 桂林电子科技大学 | S-shaped metal structure band-stop filter with notch |
| CN115332743A (en) * | 2022-07-28 | 2022-11-11 | 西安空间无线电技术研究所 | Terahertz reconfigurable filter with planar mask structure and preparation method |
| CN115332743B (en) * | 2022-07-28 | 2023-11-10 | 西安空间无线电技术研究所 | Terahertz reconfigurable filter with planar mask structure and preparation method |
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