WO2013037173A1

WO2013037173A1 - Resonant cavity and filter having same

Info

Publication number: WO2013037173A1
Application number: PCT/CN2011/083898
Authority: WO
Inventors: 刘若鹏; 栾琳; 刘京京; 苏翠; 李平军
Original assignee: 深圳光启高等理工研究院; 深圳光启创新技术有限公司
Priority date: 2011-09-16
Filing date: 2011-12-13
Publication date: 2013-03-21
Also published as: CN103000980B; CN103000980A

Abstract

The present invention relates to a resonant cavity, including a cavity body and an input end and output end provided respectively on two sidewalls of the cavity body. The cavity body is further provided therein with at least one metamaterial sheet, each metamaterial sheet including a non-metal substrate and an artificial microstructure attached to the substrate, the artificial microstructure being of a structure with a geometric figure formed by the wires of a conductive material, the artificial microstructure attached at the edge on either side of each metamaterial sheet being electrically connected to the input end and output end respectively via a metal. The present invention can be applied to realize the functions of a band stop filter using a single resonant cavity. In addition, also provided is a filter having said resonant cavity.

Description

Resonant cavity and filter having the same

The present application claims priority to Chinese Patent Application No. 2011-1027532, the entire disclosure of which is incorporated herein by reference. Technical field

The present invention relates to the field of wireless communications, and more particularly to a resonant cavity and a filter having the same. Background technique

In microwave devices, cavity filters are a very important device. The cavity filter is composed of a plurality of microwave resonators having the same shape and volume, and each cavity has a cavity of a specific shape surrounded by a conductive wall (or a magnetic conductive wall). Generally, a resonant cavity has a fixed resonant frequency, and a plurality of resonant cavities having different resonant frequencies are connected together to form a filter having a bandwidth of a certain width. In this way, the filter needs to have a certain bandwidth of band pass or band stop, and it is necessary to have a plurality of resonant cavities, resulting in a large volume defect. Summary of the invention

The technical problem to be solved by the present invention is to provide a resonant cavity capable of realizing the function of a band rejection filter in view of the above-mentioned drawbacks of the prior art.

The invention provides a resonant cavity comprising a cavity and an input end and an output end respectively mounted on side walls of the cavity. The cavity is further provided with at least one metamaterial sheet, each of the super material sheets comprising a non-metal substrate and an artificial microstructure attached to the substrate, the artificial microstructure being composed of a wire composed of a conductive material The structure of the pattern, the artificial microstructures attached to the two sides of each of the metamaterial sheets are respectively electrically connected to the input end and the output end by metal.

Wherein, the artificial microstructures attached to the two sides of each of the metamaterial sheets are respectively short-circuited by metal short-circuiting between the input end and the output end.

Wherein, the metal is in the form of a sheet, and the two side edges are respectively in contact with the artificial microstructure and the input end or the output end.

Wherein, the thickness of the sheet metal is the same as the thickness of the artificial microstructure. Wherein, the thickness of the sheet metal is greater than the thickness of the artificial microstructure.

Wherein, the metal piece is made of copper.

Wherein, the artificial microstructure and the input end and the output end are both made of a conductive material.

Wherein, there are a plurality of the artificial microstructures, and the plurality of the artificial microstructures are arranged in a rectangular array on the surface of the substrate.

Wherein, there are a plurality of the artificial microstructures, and the plurality of the artificial microstructures are arranged in an annular array on the surface of the substrate.

Wherein, the plurality of metamaterial sheets have a plurality of layers, and the plurality of metamaterial sheets are laminated in a direction perpendicular to the surface thereof.

Wherein, a plurality of the metamaterial sheets are integrally joined by mechanical connection or bonding.

Wherein, the substrate is made of ceramic, polytetrafluoroethylene, FR-4 material, ferroelectric material, ferromagnetic material or SiO ₂ .

Wherein, the artificial microstructure is an isotropic structure having four branches, and any branch is rotated 90 degrees around a center of rotation and then coincides with an adjacent branch.

Wherein, the branch road has a T shape or a derivative shape thereof.

Wherein, the branch is serpentine or spiral.

Wherein, the branch is a mixed shape of two or three of a T-shape, a serpentine shape and a spiral shape.

Wherein, the artificial microstructure is an anisotropic structure.

Wherein, the artificial microstructure comprises five I-shapes, wherein one of the I-shapes is centered, and the remaining four I-shapes are smaller than the centered I-shape, and the remaining four I-shapes are connected to the centered I-shaped Four endpoints.

Wherein, the artificial microstructure comprises two axisymmetric spirals.

Accordingly, embodiments of the present invention also provide a filter including at least one of the above-described resonant cavities.

By implementing the resonant cavity of the present invention, the function of the band stop filter can be realized with a single resonant cavity. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in the claims Not paying Other drawings can also be obtained from these drawings on the premise of inventive labor.

1 is a schematic structural view of a resonant cavity of a preferred embodiment of the present invention;

Figure 2 is a perspective view of the resonator shown in Figure 1 when it is placed upside down;

Figure 3 is an enlarged view of a portion A of the resonant cavity shown in Figure 2;

Figure 4 is a left side elevational view of the cavity of Figure 2;

Figure 5 is a simulation effect diagram of the resonant cavity shown in Figures 1 to 3;

Figure 6 is a schematic view showing the structure of the artificial microstructure in the form of an I-shaped shape;

Figure 7 is a schematic view showing the structure when the four branches of the artificial microstructure are T-shaped; Figure 8 is a schematic view showing the structure of the four branches of the artificial microstructure in a serpentine shape;

Figure 9 is a schematic view showing the structure of the four branches of the artificial microstructure in a spiral shape;

Figure 10 is a schematic view showing the structure when the artificial microstructure is anisotropic spiral;

Figure 11 is a schematic view showing the structure of the artificial microstructure in the form of another anisotropic spiral. Specific embodiment

The invention relates to a resonant cavity for a filter, the filter comprising at least one of the resonant cavities. As shown in FIG. 1, the resonant cavity includes a cavity 1, an input end 3 and an output end 4 mounted on side walls of the cavity 1. The cavity 1 has a cavity similar to a cube, and one end is open. The open face is sealed with a chamber cover 2. The innovation of the present invention lies in that a cavity 5 is provided in the cavity 1 and a metal piece 8 connecting the metamaterial layer 5 with the input terminal 3 and the output terminal 4 is provided to realize the effect of the band rejection filter.

As shown in FIG. 2, FIG. 3 and FIG. 4, at least one of the super-material sheets 5 is provided. When there are a plurality of layers, the plurality of meta-material layers 5 are perpendicular to the surface of the sheet by mechanical connection or bonding. The direction of the stack is integrated. Each of the metamaterial sheets 5 comprises a substrate 6 and at least one artificial microstructure 7 attached to the substrate 6. The substrate 6 is usually made of a non-metallic material such as polytetrafluoroethylene, epoxy resin, FR-4 material, ceramic, ferroelectric material, ferromagnetic material, SiO _{2 ,} and the like. Since its thickness is usually much smaller than its length or width, it is in the form of a sheet. The artificial microstructures 7 are attached to the surface of the sheet substrate 6. When there are a plurality of artificial microstructures 7, they are usually periodically arranged on the substrate 6, such as an annular array arrangement or a rectangular array arrangement, preferably a rectangular array row. Cloth, as shown in Figure 2. The artificial microstructure 7 is a geometrically structured structure composed of wires of a conductive material having a size within one fifth of the wavelength of the electromagnetic wave to be responsive, preferably no more than one tenth. The conductive material here is usually metal such as silver or copper, and other conductive materials. Materials such as ITO (indium tin oxide), graphite, carbon nanotubes, and the like.

The geometry of the artificial microstructure 7 can take many forms. The structure shown in Fig. 2 is a structure in which two identical "work"-shaped structures are orthogonal and the intersection point is the midpoint of the middle line connecting the two, which can be regarded as A sigmoid shape is rotated by 90 degrees, 180 degrees, and 270 degrees with the end point of the vertical line as a center of rotation, thereby obtaining four identical branches and a structure composed of the four branches. Any artificial microstructure 7 having such structural characteristics belongs to the isotropic artificial microstructure 7, that is, it has four branches, and any branch is rotated 90 degrees around a center of rotation and coincides with the adjacent branch.

The isotropic artificial microstructure 7 has many forms, as shown in Figure 7, Figure 8, and Figure 9. Each branch of the artificial microstructure 7 shown in FIG. 7 has a U-shaped derivative shape, and is connected with other structures at both ends of the U-shaped horizontal line. In this embodiment, an I-shaped structure is connected, and of course, it can also be connected. Any other shape such as a ring, a curve, a fold line extending toward the center of rotation, and the like. The artificial microstructure 7 shown in Fig. 8 has a serpentine shape for each branch, that is, a reciprocating bending of a line segment. Obviously, the branch can also be a serpentine derivative, that is, at the end of the serpentine branch. Connect line segments, curves, and more. The artificial microstructure 7 shown in Fig. 9 has a spiral shape, that is, a trajectory formed by displacing from the inside to the outside while being wound around the inside, in this example, a triangular spiral, or a rectangular spiral or a circular spiral. Similarly, the end of the spiral can also be derived by connecting wired segments, curves, and the like. It should be noted that each branch may also be a combination of two or three of a U-shape, a serpentine shape and a spiral shape. Of course, in practice, each branch may have any shape as long as it is composed of four identical The branch is composed and conforms to the characteristics of isotropic.

The artificial microstructure 7 which does not satisfy the isotropic characteristics, i.e., the anisotropic artificial microstructure 7, is also applicable in the present invention. For example, the structure shown in Fig. 6 consisting of a large I-shape and four small I-shaped shapes connected at the four end points of the large I-shape is anisotropy. Figures 10 and 11 show two helical anisotropic structures, and such artificial microstructures 7 can also be used in the present invention.

It should be noted that the above-mentioned geometric figures of Figs. 6 to 11 are composed of wires, that is, each wire represents a conductive material wire, and the wire has a certain line width and thickness, which are not shown in the drawing.

While the metamaterial is placed in the cavity 1, as shown in FIG. 2, FIG. 3, and FIG. 4, metal is disposed on both side edges of each of the metamaterial sheets 5, and the metal is in the form of a sheet in this embodiment. The metal piece 8 and the metal piece 8 may be made of any electrically conductive metal material. In the present invention, the material is preferably the same as the metal material of the artificial microstructure 7, the input end 3, and the end of the output end 4, for example, all of copper. The metal sheet 8 serves to short-circuit the artificial microstructure 7 on both sides of the super-material sheet 5 to the input terminal 3/output terminal 4. In order to save material, the thickness of the metal sheet 8 can be made comparable to the thickness of the artificial microstructure 7, of course, in order to enhance the stability, The thickness of the metal sheet 8 can be relatively large.

In order to verify the use effect of the resonant cavity of the present invention, the simulation parameters include: The resonant cavity is copper, the internal dimension of the cavity 1 is 20mm 20mm 20mm, the input end 3, the output end 4 extends into the resonant cavity The inner end is made of copper rod, the length is 3.5mm, the diameter is 2mm; the super material sheet 5 is five pieces, the total thickness is 0.49mm, the length and the width are all 10mm, which is located in the middle of the cavity; the substrate 6 is FR -4 material, thickness 0.4mm; artificial microstructure 7 has the shape of four T-shaped isotropic structures as shown in Figure 2, length and width are 0.8mm, made of copper wire, line width 0.1mm, The artificial microstructures 7 are arranged in an array of 10 x 10 matrices on the surface of the substrate 6 at a line pitch of 1 mm and a column pitch of 1 mm; the metal sheets 8 are copper sheets, 1.6 mm wide and 10 mm long, so that a row of artificial microstructures with the outermost edges 7 contact, thickness 0.018mm.

The simulation of such a cavity is carried out, and the simulation results obtained are shown in Fig. 5. It can be seen from Fig. 5 that the trend of the S11 and S21 curves is a band-stop filter at a resonant frequency of 4.9 GHz, so this cavity can be used as a band-stop filter.

The embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the specific embodiments described above, and the specific embodiments described above are merely illustrative and not restrictive, and those skilled in the art In the light of the present invention, many forms may be made without departing from the spirit and scope of the invention as claimed.

Claims

Rights request

A resonant cavity comprising a cavity and an input end and an output end respectively mounted on sidewalls of the two sides of the cavity, wherein at least one layer of metamaterial is placed in the cavity, each The metamaterial sheet layer comprises a non-metal substrate and an artificial microstructure attached to the substrate, the artificial microstructure being a geometric structure composed of wires of a conductive material, and both sides of each of the metamaterial sheets The artificial microstructures attached thereto are respectively electrically connected to the input end and the output end by metal.

2. The resonant cavity according to claim 1, wherein the artificial microstructures attached to the two sides of each of the metamaterial sheets are respectively short-circuited by metal short-circuiting between the input end and the output end.

3. The resonant cavity according to claim 2, wherein the metal is in the form of a sheet, and the two side edges are respectively in contact with the artificial microstructure and the input end or the output end.

The resonator according to claim 3, wherein the thickness of the sheet metal is the same as the thickness of the artificial microstructure.

The resonant cavity according to claim 3, wherein the thickness of the sheet metal is greater than the thickness of the artificial microstructure.

6. The resonant cavity according to claim 3, wherein the metal piece is made of copper.

The resonant cavity according to any one of claims 1 to 6, wherein the artificial microstructure and the input end and the output end are each made of a conductive material.

The resonant cavity according to any one of claims 1 to 6, wherein a plurality of the artificial microstructures are arranged in a rectangular array on the surface of the substrate.

The resonant cavity according to any one of claims 1 to 6, wherein a plurality of the artificial microstructures are arranged in an annular array on the surface of the substrate.

The resonant cavity according to any one of claims 1 to 6, wherein the plurality of metamaterial sheets have a plurality of layers, and the plurality of metamaterial sheets are laminated integrally in a direction perpendicular to the surface thereof.

11. The resonant cavity of claim 10, wherein a plurality of said metamaterial sheets are integrally joined by mechanical bonding or bonding.

The resonant cavity according to any one of claims 1 to 6, wherein the substrate is made of ceramic, polytetrafluoroethylene, FR-4 material, ferroelectric material, ferromagnetic material or SiO ₂ .

The resonant cavity according to any one of claims 1 to 6, wherein the artificial microstructure is an isotropic structure having four branches, and any branch is rotated by 90 degrees around a center of rotation. After and adjacent branches The roads coincide.

The resonant cavity according to claim 13, wherein the branch is T-shaped or derived.

15. The resonant cavity of claim 13 wherein the branch is serpentine or spiral.

16. The resonant cavity according to claim 13, wherein the branch is a mixed shape of two or three of a T-shape, a serpentine shape, and a spiral shape.

The resonator according to any one of claims 1 to 6, wherein the artificial microstructure is an anisotropic structure.

18. The resonant cavity according to claim 16, wherein the artificial microstructure comprises five I-shapes, wherein one of the I-shapes is centered, and the remaining four I-shapes are smaller than the centered I-shape, and the rest Four I-forms are connected to the four endpoints of the centered I-form.

19. The resonant cavity of claim 16 wherein said artificial microstructure comprises two axisymmetric spirals.

A filter comprising at least one resonant cavity according to any of claims 1-19.