阅读说明：本技术 一种宽频带机械可调谐滤波器 (Broadband mechanical tunable filter ) 是由 阮久福 陶治 孟子凡 兰凤 于 2021-09-03 设计创作，主要内容包括：本发明公开了一种宽频带机械可调谐滤波器,滤波器包括两个分立的谐振器以及两个分立的谐振器之间的空气层；分立的谐振器结构完全相同,包括介质层和金属谐振层,金属谐振层包括M×N个相同单元；两个分立的谐振器的金属谐振层隔着空气层相邻,通过调节空气层的厚度来改变滤波器的谐振频率,使得宽频带机械可调谐滤波器可在很宽的频率范围内实现单通带向多通带的转换以及通带位置的移动。与现有的可调谐滤波器相比,本发明具有通带数目自由变换、调谐响应快、调谐范围广、结构简单等优点。(The invention discloses a broadband mechanical tunable filter, which comprises two discrete resonators and an air layer between the two discrete resonators; the discrete resonators have the same structure and comprise dielectric layers and metal resonance layers, and each metal resonance layer comprises M multiplied by N same units; the metal resonance layers of the two separated resonators are adjacent to each other through an air layer, and the resonance frequency of the filter is changed by adjusting the thickness of the air layer, so that the broadband mechanical tunable filter can realize the conversion from a single passband to multiple passbands and the movement of the passband position in a wide frequency range. Compared with the existing tunable filter, the tunable filter has the advantages of free pass band number conversion, fast tuning response, wide tuning range, simple structure and the like.)

1. A wide-band mechanically tunable filter, characterized in that said filter is composed of two discrete resonators and an air layer between them;

the resonator is of a two-layer structure and comprises a resonance layer and a dielectric layer, wherein the resonance layer comprises M multiplied by N same units, no space exists between the adjacent units, M and N are positive integers equal to or larger than 1, and M can be larger than, equal to or smaller than N;

the distance between the resonance layer and the dielectric layer of the single discrete resonator is zero;

the medium layer material is a cycloolefin polymer; the resonance layer is made of metal;

the dielectric constant of the dielectric layer is 2.2, and the loss tangent value is 0.0007;

the resonance layers of the two resonators of the broadband mechanical tunable filter are separated by an air layer, namely the metal resonance layers of the two resonators are opposite to each other through the air layer;

the resonance layer unit structure is that four equally large gaps are formed on a square;

the side length of the square is 1000 mu m;

the shape of the gap is isosceles trapezoid, the gap is positioned at the edges of four sides of the square, the center of the gap is aligned with the center of each side, and the distance between the long bottom side of the gap, namely the isosceles trapezoid and each side is 50 micrometers; the length of the long bottom edge of the gap is 829.29 micrometers, the length of the short bottom edge of the gap is 729.29 micrometers, and the height of the gap is 50 micrometers;

the thickness of the dielectric layer of the unit is 199 mu m;

the thickness of an air layer of the broadband mechanical tunable filter is adjusted between 0mm and 2 mm;

the broadband mechanically tunable filter may provide one or more passbands with variation in air layer thickness in the range of 50-300 GHz;

the position of the passband of the broadband mechanically tunable filter moves with the thickness of the air layer.

2. The broadband mechanically tunable filter according to claim 1, wherein the thickness of the resonance layer in said unit is in the range of 0.5 μm to 1.1 μm.

3. The broadband mechanically tunable filter according to claim 1, wherein the material of the resonance layer is one of gold, silver, copper, and aluminum.

Technical Field

The invention relates to the field of microwave and terahertz functional devices, in particular to a broadband mechanical tunable filter.

Background

In recent years, with the vigorous development of terahertz technology, the demand for corresponding functional devices is higher and higher, and for a terahertz system with high integration level, a tunable filter with reliable performance is of great importance. At present, the tuning method is mostly realized by adopting special functional materials to change the equivalent electrical parameters of the filter, and specifically, the tuning method is based on temperature-sensitive materials, liquid crystals, graphene and the like. The methods have the problems of large tuning slow delay, additional bias voltage, difficulty in controlling the tuning range, high cost, complex structure and the like. In addition, in the existing tunable terahertz band-pass filter, the tunable characteristic is only the tunable frequency of the pass band, and the number of the pass bands is fixed, which also limits the application range.

Based on the above problems, how to design a terahertz filter with rapid response, simple structure, controllable tuning range and adjustable number of pass bands becomes a problem to be solved urgently in the field.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a broadband mechanical tunable filter, namely, the tuning of the frequency and the number of pass bands can be realized only by providing external pressure.

In order to achieve the above object, the present invention provides a wide-band mechanically tunable filter, characterized in that the filter is composed of two discrete resonators and an air layer therebetween;

the discrete resonators are of a two-layer structure and comprise resonance layers and dielectric layers, each resonance layer comprises M multiplied by N identical units, no space exists between every two adjacent units, M and N are positive integers equal to or larger than 1, and M can be larger than, equal to or smaller than N;

the distance between the resonance layer and the dielectric layer of the single discrete resonator is zero;

the medium layer material is a cycloolefin polymer; the resonance layer is made of metal;

the dielectric constant of the dielectric layer is 2.2, and the loss tangent value is 0.0007;

the resonance layers of two separated resonators of the broadband mechanical tunable filter are separated by an air layer, namely the metal resonance layers of the two resonators are opposite to each other through the air layer;

the resonance layer unit structure is that four equally large gaps are formed on a square;

the side length of the square is 1000 mu m;

the shape of the gap is isosceles trapezoid, the gap is positioned at the edges of four sides of the square, the center of the gap is aligned with the center of each side, and the distance between the long bottom side of the gap, namely the isosceles trapezoid and each side is 50 micrometers; the length of the long bottom edge of the gap is 829.29 micrometers, the length of the short bottom edge of the gap is 729.29 micrometers, and the height of the gap is 50 micrometers;

the thickness of the dielectric layer of the unit is 199 mu m;

the thickness of an air layer of the broadband mechanical tunable filter is adjusted between 0mm and 2 mm;

the broadband mechanically tunable filter may provide one or more passbands with variation in air layer thickness in the range of 50-300 GHz;

the position of the passband of the broadband mechanically tunable filter can move along with the change of the thickness of the air layer.

Optionally, the thicknesses of the first resonance layer and the second resonance layer range from 0.5 μm to 1.1 μm.

Optionally, the material of the first resonance layer and the second resonance layer is one of gold, silver, copper, and aluminum.

The invention has the beneficial effects that:

1. the wide-band mechanical tunable filter realizes the change of the frequency of the passband by adjusting the thickness of the air layer, and simultaneously realizes the change of the number of the passbands, namely, the single-frequency filtering is changed into the multi-frequency filtering.

2. The tuning mode of the broadband mechanical tunable filter is simple and quick in response, and tuning can be realized without bias voltage.

3. The broadband mechanical tunable filter is simple in structure, good in stability and strong in practicability.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a single unit of a resonant layer of a discrete resonator according to an embodiment of the present invention;

FIGS. 3-12 are graphs of transmission responses of embodiments of the present invention when the air layer has a thickness of 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, respectively, according to embodiments of the present invention;

the resonator comprises 1, a discrete resonator, 1-1, a resonance layer, 1-2, a dielectric layer, 2, an air layer, 3 and a gap.

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. The object of the present invention is to provide a wide band mechanically tunable filter consisting of two separate resonators 1 with an air layer 2 between them, as shown in fig. 1. The thickness of the air layer 2 is t, and the range of t is 0-2 mm. The discrete resonator 1 consists of a resonance layer 1-1 and a dielectric layer 1-2; the spacing between the resonant layer 1-1 and the dielectric layer 1-2 of each discrete resonator is zero. The material of the resonance layer 1-1 is metal copper, and the thickness is 0.8 mu m; the dielectric layer 1-2 is made of polyethylene terephthalate (PET) with a thickness t₁It was 199 μm, the dielectric constant was 2.2 and the loss tangent was 0.0007. As shown in fig. 1, the resonance layers 1-1 of two separate resonators 1 of the wide-band mechanically tunable filter are separated by an air layer 2, i.e., the resonance layers 1-1 of two separate resonators 1 are opposed to each other with the air layer 2 interposed therebetween. The resonant layer 1-1 includes M × N identical cells with no spacing between adjacent cells, M and N are positive integers equal to or greater than 1, and M, N in this example is 20.

As shown in fig. 2, the unit structure of the resonance layer is a square with four equally large slots 3; the side length P of the square is 1000 mu m; the shape of the gap 3 is an isosceles trapezoid, the gap 3 is positioned at the edges of four sides of the square, the center of the gap 3 is aligned with the center of each side, and the distance between the gap 3 and each side, namely the distance w between the long bottom side of the isosceles trapezoid and each side, is 50 micrometers; the slit 3 has a long bottom side length S of 829.29 μm, a short bottom side length d of 729.29 μm, and a width h of 50 μm.

As shown in fig. 3, when the thickness of the air layer 2 is 0.2mm, the filter according to the embodiment of the present invention exhibits single-pass band characteristics, in which the transmission coefficient at the center frequency of 145GHz is 0.917, and the bandwidth (-3dB, i.e., the transmission coefficient is 0.707, the same applies hereinafter) is 21.5GHz, which is 135.5 to 157 GHz.

As shown in fig. 4, when the thickness of the air layer 2 is increased from 0.2mm to 0.4mm, the filter of the embodiment of the present invention changes from a single passband at 0.2mm to a double passband, the original passband at 145GHz is basically unchanged, i.e. the central frequency and the bandwidth do not greatly vary: the center frequency is changed from 145GHz to 141GHz (the transmission coefficient is 0.901), and the bandwidth is changed from 21.5GHz of 135.5-157GHz to 21GHz of 131-152 GHz; and then a narrow pass band of 5.5GHz with center frequency of 289.5GHz (transmission coefficient of 0.906) and bandwidth of 286-291.5GHz is added.

As shown in fig. 5, when the thickness of the air layer 2 is further increased to 0.6mm, the filter of the embodiment of the present invention continues to exhibit dual-pass characteristics, and the original pass band at 145GHz remains substantially unchanged, i.e. the center frequency and the bandwidth do not vary much: the center frequency was changed to 137GHz (transmission coefficient was 0.917), and the bandwidth was changed to 27GHz, which is 125-152 GHz; and a narrow pass band of 6.5GHz with the center frequency of 203GHz (transmission coefficient of 0.971) and the bandwidth of 199.5-206GHz is newly appeared at the moment.

As shown in fig. 6, when the thickness of the air layer 2 continues to increase and become 0.8mm, the filter of the embodiment of the present invention continues to exhibit the single pass band characteristic, the maximum transmission frequency of the pass band is 142GHz, and the bandwidth is 63GHz, which is 115-178 GHz. The single pass band is especially wide and is formed by combining the two original pass bands, namely combining the pass band at 145GHz when the thickness of the air layer is 0.2mm and the frequency at 203GHz when the thickness of the air layer is 0.6mm after moving to the low frequency and changing to the central frequency of 169 GHz.

As shown in fig. 7, when the thickness of the air layer 2 is further increased to 1.0mm, the filter according to the embodiment of the present invention exhibits dual-pass characteristics, where the two pass-bands are: a wider passband at 31GHz with a center frequency of 152GHz (transmission coefficient of 0.974), a bandwidth of 132-163GHz, and a narrow passband at 7GHz with a center frequency of 107GHz (transmission coefficient of 0.949), and a bandwidth of 105-112 GHz. Namely, when the thickness of the air layer is 0.8mm, two small pass bands which form a wide single pass band with the bandwidth of 63GHz are separated again: the passband at 145GHz when the thickness of the air layer is 0.2mm is basically unchanged, except that the small amplitude high frequency movement of the central frequency is changed into 152GHz (transmission coefficient is 0.974), and the bandwidth is 132 GHz and 31GHz of 163 GHz; while the passband having a center frequency of 169GHz at an air layer thickness of 0.8mm continues to move toward a low frequency, the center frequency becomes 107GHz (transmission coefficient of 0.949), and the bandwidth becomes 7GHz, which is 105 GHz and 112 GHz.

As shown in fig. 8, when the thickness of the air layer 2 is continuously increased to 1.2mm, the filter according to the embodiment of the present invention exhibits a three-passband characteristic, where the three passbands are: a 6GHz narrow passband with a center frequency of 96.5GHz (transmission coefficient of 0.929) and a bandwidth of 92.25-98.25 GHz; a wider passband of 20GHz with a center frequency of 146GHz (transmission coefficient of 0.912) and a bandwidth of 135.75-155.75 GHz; a center frequency of 220.5GHz (transmission coefficient of 0.954), and a very narrow passband less than 2GHz with a bandwidth of 219.5-221.25 GHz.

As shown in fig. 9, when the thickness of the air layer 2 is further increased to 1.4mm, the filter according to the embodiment of the present invention further exhibits a three-passband characteristic, where the three passbands are: a very narrow passband of 1.5GHz with a center frequency of 86.5GHz (transmission coefficient of 0.912) and a bandwidth of 85.75-87.25 GHz; a wider passband of 17.5GHz with a center frequency of 143GHz (transmission coefficient of 0.885) and a bandwidth of 135-152.5 GHz; a narrower passband of 4.5GHz with a center frequency of 196.25GHz (transmission coefficient of 0.972) and a bandwidth of 193.75-198.25 GHz. It can be seen that the three passbands at this time are shifted toward lower frequencies from the corresponding three passbands (center frequencies) for an air layer thickness of 1.2 mm.

As shown in fig. 10, when the thickness of the air layer 2 is further increased to 1.6mm, the filter according to the embodiment of the present invention further exhibits a three-passband characteristic, where the three passbands are: a very narrow passband of 0.75GHz centered at 77.75GHz (transmission coefficient of 0.9) and having a bandwidth of 77.5-78.25 GHz; a wider passband of 22.5GHz with a center frequency of 140GHz (transmission coefficient of 0.939) and a bandwidth of 130.5-152.5 GHz; a narrow passband of 8.25GHz with a center frequency of 178GHz (transmission coefficient of 0.976) and a bandwidth of 173-181.25 GHz. It can be seen that the three passbands at this time continue to shift toward the lower frequencies corresponding to the three passbands (center frequencies) for an air layer thickness of 1.6 mm.

As shown in fig. 11, when the thickness of the air layer 2 is further increased to 1.8mm, the filter of the embodiment of the present invention mainly exhibits a wider single pass band characteristic, the pass band being: a very wide passband of 43GHz with a center frequency of 142.5GHz (transmission coefficient of 0.967) and a bandwidth of 126-169 GHz.

As shown in fig. 12, when the thickness of the air layer 2 is further increased to 2.0mm, the filter according to the embodiment of the present invention exhibits dual-pass characteristics, in which the pass-bands are: a very wide passband of 41GHz with a center frequency of 150.5GHz (transmission coefficient of 0.971) and a bandwidth of 119.75-160.75 GHz; a very narrow passband of 1.75GHz with a center frequency of 209.5GHz (transmission coefficient of 0.965) and a bandwidth of 208.5-210.25 GHz.

The broadband mechanical tunable filter of the embodiment of the invention can provide one, two or three passbands along with the thickness change of the air layer 2 in the range of 50-300GHz, and the positions of the passbands move along with the thickness change of the air layer.

The principles and embodiments of the present invention have been explained herein using specific embodiments, which are merely used to help understand the method and its core ideas of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.