CN100541906C - Super-small resonant cavity - Google Patents

Abstract

Super-small resonant cavity, it relates to a kind of resonant cavity.For solve resonant cavity exist miniaturization the theoretical size limit and based on the miniaturization resonant cavity of three-dimensional anisotropic media can not processing and manufacturing under existing technical merit problem, the present invention includes a micron wave or millimeter wave resonant cavity (1), the negative magnetoconductivity medium (2) that in the chamber of micron wave or millimeter wave resonant cavity (1), has the leftward space of occupying, described negative magnetoconductivity medium (2) is the one dimension anisotropic media, and the width of resonant cavity (1) is less than 1/2nd operation wavelengths.It is according to the tunnel effect of electromagnetic wave in negative magnetoconductivity medium and the generation of negative dielectric constant dielectric interface, make the resonance frequency of resonant cavity be no longer dependent on the size of resonant cavity, and the first-selected one-dimentional structure of using of anisotropic media (negative dielectric constant dielectric and negative magnetoconductivity medium), be highly susceptible to making, under existing technical merit, just realized the purpose of the extra small resonant cavity of low-cost manufacturing.

Description

Super-small resonant cavity

Technical field

The present invention relates to a kind of resonant cavity, the resonant cavity of especially a kind of microminiature micron wave, millimeter wave.

Background technology

Anisotropic media is the artificial electromagnetic medium of a kind of novel periodic structure of phase late 1990s appearance, it has the dielectric constant of negative value and the magnetic permeability of negative value simultaneously, cause the electromagnetic electric field E that in this medium, propagates, magnetic field H and wave vector k three constitute left-handed system, rather than follow the right-hand rule of conventional medium, anisotropic media so it is otherwise known as.At present, along with people's going deep into to anisotropic media understanding, the connotation and extension of anisotropic media notion is all constantly enlarging, anisotropic media not only refers to the medium that has negative permittivity and negative magnetoconductivity simultaneously, and the special medium that has negative permittivity separately or have negative magnetoconductivity is separately also put under the category of anisotropic media.

Anisotropic media is because its unusual electromagnetic property at the beginning of it comes out, just has been considered to extremely application prospects.Nowadays, number of research projects is devoted to utilize the unusual electromagnetic property of anisotropic media to dwindle micron wave device volume or area occupied.At present, successfully designed based on the miniaturized patch antenna of anisotropic media, miniaturization directional coupler, miniaturization phase shifter etc. by different in the world research groups.Especially, Engheta pointed out to utilize the crossover of one dimension anisotropic media and generic media to construct a kind of miniaturization resonant cavity in 2002, and its length can be much smaller than the Semi-resonance wavelength, thereby realized dwindling the purpose of resonant cavity size.But imperfection very on this miniaturization resonant theory: it can only dwindle the length of resonant cavity, but can't dwindle the width of resonant cavity, causing the lower size limit of resonant cavity to be actually by housing width determines, make its theoretical limit that has a miniaturization, for further developing of research is provided with impassable obstacle.And 2006, the design theory of the another kind of miniaturization resonant cavity that professor Feng Yijun of Nanjing University proposes has remedied the theoretical defects of Engheta resonant cavity to a certain extent, its method is only to need that the one dimension anisotropic media in the Engheta resonant cavity is changed to three-dimensional anisotropic media and get final product.Though method is simple, but the operation principle with the Engheta resonant cavity has a great difference, the electromagnetic field regularity of distribution of inside cavity is also different, greatest differences on the also this just operation principle just makes the length that this novel resonant cavity miniaturization method not only can dwindle traditional resonant cavity, can also dwindle the width of resonant cavity, thereby realize theoretic breakthrough with respect to the Engheta resonant cavity.Yet, undeniablely be, still there is incomplete place in this resonant cavity: it requires is three-dimensional anisotropic media, and in fact from the present development level of anisotropic media, the three-dimensional anisotropic media of function admirable is difficult to be devised, three-dimensional anisotropic media design studies itself is exactly a hang-up of anisotropic media research field, so far still do not have a three-dimensional anisotropic media of being approved by the people to occur from calendar year 2001 first anisotropic media appearance, can find out that therefrom the design of three-dimensional anisotropic media has suitable difficulty yet.In such cases, though the Feng Shi resonant cavity is theoretical fairly perfect, be difficult to but realize that this is provided with obstacle for it further is applied undoubtedly, has also reduced the using value of itself.

Summary of the invention

There is the theoretical size limit of miniaturization and, the present invention proposes a kind of super-small resonant cavity in order to solve resonant cavity based on the problem that the miniaturization resonant cavity of three-dimensional anisotropic media can not processing and manufacturing under existing technical merit.

The technical solution adopted for the present invention to solve the technical problems is: super-small resonant cavity comprises a micron wave or millimeter wave resonant cavity, the negative magnetoconductivity medium that in the chamber of micron wave or millimeter wave resonant cavity, has the leftward space of occupying, described negative magnetoconductivity medium is the one dimension anisotropic media, and the width of resonant cavity is less than 1/2nd operation wavelengths; Described negative magnetoconductivity medium is to constitute among being embedded in non magnetic filler by the alternate grid of multilayer, and grid are sheet frames that have at least two fractures of being made by electric conducting material, and it is staggered mutually that the fracture of each grid is adjacent the fracture of grid.

The present invention is according to the tunnel effect of electromagnetic wave in negative magnetoconductivity medium and the generation of negative dielectric constant dielectric interface, make the resonance frequency of resonant cavity be no longer dependent on the size of resonant cavity, thereby the purpose that the resonant cavity volume is dwindled in realization, it should be noted that, the negative magnetoconductivity medium can be realized making under prior art, the first-selected one dimension of anisotropic media (negative dielectric constant dielectric and negative magnetoconductivity medium) that we use, be easier to low-cost the manufacturing.

The invention has the beneficial effects as follows, super-small resonant cavity is a principle of utilizing the tunnel effect that electromagnetic wave can take place at negative magnetoconductivity medium and negative dielectric constant dielectric interface, make the resonance frequency of resonant cavity be no longer dependent on the size of resonant cavity, and negative dielectric constant dielectric and negative magnetoconductivity medium that the present invention uses are first-selected one-dimentional structures, be highly susceptible to making, under existing technical merit, can realize the low-cost super-small resonant cavity of making, it can be applied to radio communication, the electronic circuit in micron wave field and device, the design of antenna miniaturization and manufacturing, application are very extensive.

Description of drawings

Fig. 1 is a volume rendering structure chart of the present invention, and Fig. 2 is the front view of negative magnetoconductivity medium among Fig. 1, and Fig. 3 is the A-A face cutaway view of multi-layer gate 3 among Fig. 2, and Fig. 4 is the cutaway view of bowing of Fig. 2, and Fig. 5 is an electromagnetism isoboles of the present invention.

Embodiment

Embodiment one: with reference to Fig. 1, present embodiment is the negative magnetoconductivity medium 2 that has the leftward space of occupying in the chamber of micron wave or millimeter wave resonant cavity 1.

Be used for determining that the theoretical derivation of above-mentioned design is as follows:

According to Theory of Electromagnetic Field, this super-small resonant cavity will have identical resonance characteristic with electromagnetism isoboles shown in Figure 5

Area I I describes resonant cavity and fills the generic media part among Fig. 5, and area I is described resonant cavity and filled negative magnetoconductivity medium part, and the gross thickness in two zones is much smaller than half operation wavelength.Suppose that there is a directions X current source in (Z=0) between I and II, its surface current density is J _s(x, y, z)=I ₀δ (z), then this current source is respectively at the electromagnetic field of area I and area I I generation

$E_1={\mathrm{Ae}}^{-j{k}_{1}z}+{\mathrm{Be}}^{j{k}_{1}z}$

$H_1=-\frac{A}{{\mathrm{\η}}_1}{e}^{-j{k}_{1}z}+\frac{B}{{\mathrm{\η}}_1}{e}^{j{k}_{1}z}$

(1)

${\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="C20071007177500081.png,C20071007177500085.png"\; state="\{\{state\}\}">E</figure-callout>}}_2={\mathrm{Ce}}^{j{k}_{2}z}+{\mathrm{De}}^{-j{k}_{2}z}$

${\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="C20071007177500081.png,C20071007177500085.png"\; state="\{\{state\}\}">H</figure-callout>}}_2=\frac{C}{{\mathrm{\&eta;}}_2}{e}^{j{k}_{2}z}-\frac{D}{{\mathrm{\&eta;}}_2}{e}^{-j{k}_{2}z}$

Wherein, E ₁, E ₂And H ₁, H ₂Be respectively area I, the electric field strength of II and magnetic field intensity; k ₁, k ₂And η ₁, η ₂Be respectively area I, the transmission of II and wave impedance; A, B, C, D is respectively area I, the electromagnetic field intensity coefficient of II, and they have following expression formula

$A=-\frac{I_0{Z}_{\mathrm{total}}}{1-e^{-j2k_1{d}_1}}$

$B=\frac{I_0{Z}_{\mathrm{total}}{e}^{-j2k_1{d}_1}}{1-e^{-j2k_1{d}_1}}$

(2)

$C=-\frac{I_0{Z}_{\mathrm{total}}}{1-e^{-j2k_2{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="C20071007177500081.png,C20071007177500085.png"\; state="\{\{state\}\}">d</figure-callout>}}_2}}$

$D=\frac{I_0{Z}_{\mathrm{total}}{e}^{-j2k_2{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="C20071007177500081.png,C20071007177500085.png"\; state="\{\{state\}\}">d</figure-callout>}}_2}}{1-e^{-j2k_2{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="C20071007177500081.png,C20071007177500085.png"\; state="\{\{state\}\}">d</figure-callout>}}_2}}$

Wherein, Z _TotalBe total input impedance of being looked to both sides by current source, it is by the input impedance Z of area I _{In, 1}Input impedance Z with area I I _In.2And even constitute, its expression formula is

$Z_{\mathrm{total}}=\frac{Z_{\mathrm{in},1}{Z}_{\mathrm{in},2}}{Z_{\mathrm{in},1}+Z_{\mathrm{in},2}}=\frac{{\mathrm{\&eta;}}_1{\mathrm{\&eta;}}_2(1-e^{-j2k_1{d}_1})(1-e^{-j2k_2{d}_2})}{{\mathrm{\&eta;}}_1(1-e^{-j2k_1{d}_1})(1+e^{-j2k_2{d}_2})+{\mathrm{\&eta;}}_2(1+e^{-j2k_1{d}_1})(1-e^{-j2k_2{d}_2})}---\left(3\right)$

Work as Z as can be seen by (1), (2) and (3) _{In, 1}+ Z _{In, 2}=0 o'clock, Z _Total-＞∞, it is infinitely great that the electromagnetic field intensity among area I and the II will be tending towards, and resonance effect promptly takes place, so Z _{In, 1}+ Z _{In, 2}=0 is called as condition of resonance.According to document, under the sub-wavelength condition, this condition of resonance has two classes to have separating of physical significance: i) work as η ₁, η ₂Symbol is identical, and k ₁And k ₂During opposite in sign, condition of resonance is met, especially, works as η ₁=η ₂And k ₁d ₁=-k ₂d ₂The time, according to (3) Z is arranged _{In, 1}+ Z _{In, 2}=0, such physical significance of separating representative be among area I and the area I I one be filled generic media another be filled anisotropic media, this theoretical foundation of Engheta sub-wavelength resonant cavity just as can be seen; Ii) work as k ₁, k ₂Symbol is identical, and η ₁And η ₂Condition of resonance is met, especially, works as η ₁=-η ₂And k ₁d ₁=k ₂d ₂The time, according to (3) Z is arranged _{In, 1}+ Z _{In, 2}=0.Below we will prove electromagnetism isoboles shown in Figure 2 and can satisfy the requirement that condition of resonance second class is separated fully.

In Fig. 2, for area I because μ ₁＜0, ε ₁＞0, so $k_1=\sqrt{{\mathrm{\&mu;}}_1{\mathrm{\&epsiv;}}_1}=j{\mathrm{\&alpha;}}_1,$ Wherein ${\mathrm{\&alpha;}}_1=\sqrt{\left|{\mathrm{\&mu;}}_1{\mathrm{\&epsiv;}}_1\right|}<0$ If (α ₁＞0, mean that energy transmits from the no source space of unlimited distance, has violated law of conservation of energy), at this moment, ${\mathrm{\&eta;}}_1=\frac{k_1}{{\mathrm{\&epsiv;}}_1}=j\frac{{\mathrm{\&alpha;}}_1}{{\mathrm{\&epsiv;}}_1}=j{X}_1,$ Wherein $X_1=\frac{{\mathrm{\&alpha;}}_1}{{\mathrm{\&epsiv;}}_1}>0;$ For area I I because μ ₂＞0, ε ₂＜0, so ${\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="C20071007177500081.png,C20071007177500085.png"\; state="\{\{state\}\}">k</figure-callout>}}_2=\sqrt{{\mathrm{\&mu;}}_2{\mathrm{\&epsiv;}}_2}=j{\mathrm{\&alpha;}}_2,$ Wherein ${\mathrm{\&alpha;}}_2=\sqrt{\left|{\mathrm{\&mu;}}_2{\mathrm{\&epsiv;}}_2\right|}<0$ If (α ₂＞0, mean that equally energy transmits from the no source space of unlimited distance, has violated law of conservation of energy), at this moment, ${\mathrm{\&eta;}}_2=\frac{{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="C20071007177500081.png,C20071007177500085.png"\; state="\{\{state\}\}">k</figure-callout>}}_2}{{\mathrm{\&epsiv;}}_2}=j\frac{{\mathrm{\&alpha;}}_2}{{\mathrm{\&epsiv;}}_2}=\mathrm{<figure-callout\; id="2"\; label="j\; X"\; filenames="C20071007177500081.png,C20071007177500085.png"\; state="\{\{state\}\}">j</figure-callout>}{X}_{}{}_2,$ Wherein ${\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="C20071007177500081.png,C20071007177500085.png"\; state="\{\{state\}\}">X</figure-callout>}}_2=\frac{{\mathrm{\&alpha;}}_2}{{\mathrm{\&epsiv;}}_2}<0.$ This shows that electromagnetism isoboles shown in Figure 2 satisfies the requirement that condition of resonance second class is separated, can produce resonance.As experiment, the volume that we have designed a basic mode resonance frequency is 10.3GHz has only 4.58 * 5.08 * 2.29mm ³Microminiature sub-wavelength resonant cavity, on the resonance frequency of 10.3GHz, produced expected effect, this super-small resonant cavity is far smaller than the minimum dimension value that traditional resonant cavity can reach, this explanation the present invention can implement.

Embodiment two: with reference to Fig. 2, Fig. 3 and Fig. 4, the difference of present embodiment and embodiment one is, negative magnetoconductivity medium 2 is to constitute among being embedded in non magnetic filler 4 by the alternate grid 3 of multilayer, grid 3 are sheet frames that have at least two fractures of being made by electric conducting material, it is staggered mutually that the fracture of each grid 3 is adjacent the fracture of grid 3, and other compositions are identical with embodiment one with annexation.Can produce one dimension negative magnetoconductivity on the fore-and-aft direction through testing this structure, and simple in structure, be easy to make.

Embodiment three: with reference to Fig. 2 and Fig. 4, the difference of present embodiment and embodiment one, two is, non magnetic filler 4 is Teflon materials, and other compositions are identical with embodiment one, two with annexation.The Teflon material has superior ageing resistace.

Claims (2)

1. super-small resonant cavity, it comprises a micron wave or millimeter wave resonant cavity (1), it is characterized in that: the negative magnetoconductivity medium (2) that in the chamber of micron wave or millimeter wave resonant cavity (1), has the leftward space of occupying, described negative magnetoconductivity medium (2) is the one dimension anisotropic media, and the width of resonant cavity (1) is less than 1/2nd operation wavelengths; Described negative magnetoconductivity medium (2) is to constitute among being embedded in non magnetic filler (4) by the alternate grid of multilayer (3), grid (3) are the sheet frames of being made by electric conducting material that has at least two fractures, and it is staggered mutually that the fracture of each grid (3) is adjacent the fracture of grid.

2. super-small resonant cavity according to claim 1, it is characterized in that: non magnetic filler (4) is the Teflon material.

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