CN106053956A - Material dielectric constant testing system and testing method based on same - Google Patents

Abstract

The invention relates to the technical field of microwave testing, and particularly relates to a material dielectric constant testing system and a testing method based on the same. The material dielectric constant testing system comprises a coaxial resonant cavity and a control system, wherein the coaxial resonant cavity comprises a cavity body and a probe reaching out of the cavity body; the control system is used for providing microwave input signals for the coaxial resonant cavity, the probe forms an electromagnetic field outside the cavity body, and a to-be-tested sample changes microwave output signals for the coaxial resonant cavity through interference with the electromagnetic field; and the control system analyzes and calculates the microwave output signals before and after the to-be-tested sample is placed to obtain the dielectric constant of the to-be-tested sample. The material dielectric constant testing system has the advantages that the data processing is simple; the testing efficiency is high; and the probe reaching out of the cavity body carried out scanning-type detection on the to-be-tested sample, and the testing speed is quick. The invention also provides a testing method based on the above material dielectric constant testing system. The testing efficiency is high, and the testing speed is quick.

Description

Material dielectric constant test system and method for testing based on this test system

[technical field]

The present invention relates to microwave testing field, be specifically related to a kind of material dielectric constant test system and based on this survey The method of testing of test system.

[background technology]

Dielectric constant is the electromagnetic parameter that material is important, and during by materials application to microwave technical field, dielectric constant is to comment The Main Basis of its performance of valency, therefore tests significant to material dielectric constant.

At present, the method for testing to material dielectric constant mainly has network parameter method of testing resonant cavity method of testing.Network Parameter testing method includes Transmission line method, free-space Method etc., and its measurement sensitivity is relatively low, is mainly used in high loss microwave material Test.Resonant-cavity Method has highly sensitive advantage, can the test of high loss microwave material, can be used for low-loss microwave material The test of material.

But utilize the dielectric constant of Resonant-cavity Method test material, operate time-consuming test speed slow, it is impossible to meet test need Ask.

[summary of the invention]

For overcoming the slow technical problem of current material dielectric constant test speed, the invention provides a kind of test speed fast Material dielectric constant test system and method for testing based on this test system.

The present invention solves the scheme of technical problem and is to provide a kind of material dielectric constant test system, including coaxial resonant cavity And control system；Described coaxial resonant cavity includes cavity and stretches out the probe of cavity；Described control system is used for providing the most humorous Shake the microwave input signal in chamber, and described probe forms electromagnetic field outside described cavity, and testing sample is by doing this electromagnetic field Disturb thus change the microwave output signal of described coaxial resonant cavity；Described control system is additionally operable to analyze the microwave of coaxial resonant cavity Output signal；Described control system is to be measured by being analyzed the microwave output signal placed before and after testing sample being calculated The dielectric constant of sample.

Preferably, described cavity is circle ring column, and the exradius of this circle ring column is (3-5) with the ratio of inner circle radius: 1。

Preferably, described material dielectric constant test system also includes that data base, described data base are that coaxial resonant cavity is empty Data acquisition system during cavity-like state.

Preferably, described material dielectric constant test system also includes actuator and sample mounting table, and described sample is placed Platform is used for placing sample；Described actuator can regulate described sample mounting table and the position of described coaxial resonant cavity.

Preferably, described actuator control described coaxial resonant cavity be axially moveable, described sample mounting table with axially Move in vertical plane.

Preferably, the height adjustable of described cavity, the height of described cavity is more than circle ring column exradius and annulus post Internal radius of circle sum.

Preferably, in described cavity, the one end near described probe arranges dielectric layer, the shape of dielectric layer and cavity phase Join；Described dielectric layer is prepared by white stone, and its dielectric constant is more than 1, in the height of described dielectric layer and the circle ring column of cavity Radius of circle ratio be (1.5-2.5): 1.

Preferably, described coaxial resonant cavity includes the coupling mechanism being connected with control system, described coupling mechanism include to A few coupling ring, the radius of described coupling ring is (0.5-1) with the ratio of the circle ring column inner circle radius of cavity: 1.

The present invention also provides for a kind of method of testing based on above-mentioned material dielectric constant test system, comprises the following steps: Resonant frequency during acquisition coaxial resonant cavity cavity and quality factor；Place sample；Carry out sweep check, after obtaining placing sample The resonant frequency of coaxial resonant cavity and quality factor；The resonant frequency before and after sample and quality factor is placed according to coaxial resonant cavity Calculate the dielectric constant of sample.

Preferably, resonant frequency and quality factor during described coaxial resonant cavity cavity are obtained by a data base, set up Described data base comprises the following steps: record chamber length and medium layer information；Carry out sweep check obtain resonant frequency and quality because of Number；Record resonant frequency and quality factor；Resonant frequency sweep check obtained and quality factor carry out record, and with remembered The chamber length of record is corresponding with medium layer information；Regulation chamber length or replacing dielectric layer；Repeat abovementioned steps and store data.

Compared with prior art, a kind of material dielectric constant test system that the present invention provides, it includes coaxial resonant cavity And control system.Described coaxial resonant cavity includes cavity and stretches out the probe of cavity；Described control system is used for providing the most humorous Shake the microwave input signal in chamber, and described probe forms electromagnetic field outside described cavity, and testing sample is by doing this electromagnetic field Disturb thus change the microwave output signal of described coaxial resonant cavity；Described control system is additionally operable to analyze the microwave of coaxial resonant cavity Output signal；Analytical calculation before and after described microwave output signal is changed by described control system by testing sample obtains to be measured The dielectric constant of sample.This material dielectric constant test system only needs to test resonant frequency and the quality factor of coaxial resonant cavity, Then calculated the dielectric constant that i.e. can get sample by two formula, data process simple, and testing efficiency is high.And this material Dielectric constant test system is scanned formula by the probe of coaxial resonant cavity and detects, and only testing sample need to be positioned over probe and exist In the outer electromagnetic field formed of cavity.Can be mobile coaxial resonant cavity thus drive probe so that testing sample is positioned at In the electromagnetic field that probe is formed；Can certainly directly change testing sample so that it is be positioned in the electromagnetic field that probe is formed. Owing to testing sample is positioned at outside the cavity of coaxial resonant cavity, simple operation is quick, is effectively improved test speed, can be at short notice Test a large amount of sample, it is possible to achieve material high flux is tested.

The present invention also provides for a kind of method of testing based on above-mentioned material dielectric constant test system, has testing sample Dielectric constant testing efficiency high, the advantage that test speed is fast.

[accompanying drawing explanation]

Fig. 1 is the structural representation of the coaxial resonant cavity of material dielectric constant of the present invention test system.

Fig. 2 is the cross-sectional schematic of A-A in Fig. 1.

Fig. 3 is the enlarged diagram in B portion in Fig. 2.

Fig. 4 is the structural representation of coaxial resonant cavity in some preferred embodiments of the invention.

Fig. 5 is coaxial resonant cavity difference outer conductor radius and the inner wire radius of material dielectric constant of the present invention test system Ratio coaxial resonant cavity harmonic wave affected schematic diagram.

Fig. 6 is the humorous of the material dielectric constant of the present invention test coaxial resonant cavity first-harmonic of system, 3 order harmonicses and 5 order harmonicses The change schematic diagram that vibration frequency increases with the ratio of outer conductor radius with inner wire radius.

Fig. 7 is the material dielectric constant of the present invention test coaxial resonant cavity first-harmonic of system, 3 order harmonicses and the product of 5 order harmonicses The change schematic diagram that prime factor increases with the ratio of outer conductor radius with inner wire radius.

Fig. 8 is that the coaxial resonant cavity difference inner wire radius of material dielectric constant of the present invention test system is to coaxial resonant cavity Harmonic wave affect schematic diagram.

Fig. 9 is that the coaxial resonant cavity different cavity length of material dielectric constant of the present invention test system is to coaxial resonant cavity harmonic wave Affect schematic diagram.

Figure 10 is that the coaxial resonant cavity different medium layer height of material dielectric constant of the present invention test system is to coaxial resonance Chamber harmonic wave affect schematic diagram.

Figure 11 is that the resonant frequency of the coaxial resonant cavity first-harmonic of material dielectric constant of the present invention test system is with medium floor height The change schematic diagram that degree increases.

Figure 12 is that the quality factor of the coaxial resonant cavity first-harmonic of material dielectric constant of the present invention test system are with medium floor height The change schematic diagram that degree increases.

Figure 13 is that the coaxial resonant cavity difference coupling ring radius of material dielectric constant of the present invention test system is to coaxial resonance Chamber harmonic wave affect schematic diagram.

Figure 14 is the schematic diagram of the coaxial resonant cavity equivalent circuit of material dielectric constant of the present invention test system.

Figure 15 is the structural representation of material dielectric constant of the present invention test system.

Figure 16 is the control principle schematic diagram of material dielectric constant of the present invention test system.

Figure 17 is the structural representation of the sample of material dielectric constant of the present invention test system.

Figure 18 is the schematic flow sheet setting up data base of material dielectric constant of the present invention test system.

Figure 19 is the schematic flow sheet of material dielectric constant method of testing of the present invention.

[detailed description of the invention]

In order to make the purpose of the present invention, technical scheme and advantage are clearer, below in conjunction with accompanying drawing and embodiment, The present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, It is not intended to limit the present invention.

First embodiment of the invention provides a kind of coaxial resonant cavity 10

Shown in Fig. 1, Fig. 2, described coaxial resonant cavity 10, including coupling mechanism 14 and cavity 19.Described coupling mechanism 14 excitation of microwave and couplings in the cavity 19, i.e. input microwave in cavity 19 and form agitating of cavity 19, and to chamber In body 19, microwave signal turnover couples and exports.Described coaxial resonant cavity 10 also includes the probe 113 stretching out cavity 19, described spy Pin 113 is coaxially disposed with described cavity 19.By the incentive action of coupling mechanism 14, form electromagnetic field in cavity 19, by setting Put described probe 113, the electromagnetic field that a field intensity is concentrated very much, the electric field of this electromagnetic field can be formed at the needle point of probe 113 Line 115 is distributed the most as shown in Figure 3.

Described cavity 19 is in circle ring column, and the exradius of this circle ring column is (3-5) with the ratio of inner circle radius: 1.Work as circle The exradius of ring cylinder is (3-5) with the ratio of inner circle radius: when 1, the high-order harmonic wave of described coaxial resonant cavity 10, as humorous in three rank The neighbouring clutter of ripple and five order harmonicses is few, and high-order harmonic wave has higher quality factor.And the resonant frequency of high-order harmonic wave is bright Aobvious higher than first-harmonic, as the resonant frequency of three order harmonicses and five order harmonicses is about three times and five times of the resonant frequency of first-harmonic, therefore On the basis of need not reduce coaxial resonant cavity size, by controlling exradius and the circle of the circle ring column of described cavity 19 The ratio of the inner circle radius of ring cylinder is (3-5): 1, can be effectively improved resonant frequency.Wherein, optimum is described cavity 19 annulus The exradius of cylinder is 4:1 with the ratio of inner circle radius, on the premise of ensureing high quality factor, obtains the same of high resonant frequency Axle resonator cavity 10.

The height adjustable of described cavity 19, the long h in chamber of the most described coaxial resonant cavity 10 is adjustable.High by regulation cavity 19 Degree, namely adjusts the long h in chamber, can change the resonant frequency of described coaxial resonant cavity 10, and the long h in described chamber gets over small bore coaxial cable resonator cavity 10 Resonant frequency the highest.When therefore regulating the height of cavity 19, the resonant frequency of coaxial resonant cavity 10 changes the most therewith, its change Scope is the resonant frequency range of described coaxial resonant cavity 10.Owing to controlling the cylindrical half of the circle ring column of described cavity 19 Footpath is (3-5) with the ratio of the inner circle radius of circle ring column: 1, and the resonant frequency of coaxial resonant cavity 10 is high, therefore this coaxial resonant cavity The resonant frequency range width of 10.And by regulating the height of cavity 19, the resonant frequency of coaxial resonant cavity 10 is at described resonance Frequency range consecutive variations, therefore can quickly adjust institute by changing the height of cavity 19 in described resonant frequency range State the resonant frequency of coaxial resonant cavity 10.

Concrete, as shown in Figures 1 and 2, in described cavity 19, the slide block that can move along cavity 19 axial direction is set 124.It is axially moveable slide block 124, the long h in chamber, simple in construction can be changed.Preferably, described coaxial resonant cavity 10 wraps further Including the adjusting part for moving slide block 124, described adjusting part includes the expansion link 22 being connected with slide block 124 and controls to stretch The flexible actuator 21 of contracting bar 22.The telescopic band movable slider 124 of described expansion link 22 in axial direction moves, thus it is long to change chamber H, so arranges and can regulate the long h in chamber fast and accurately.But the long h in chamber the least time, in the microwave signal of output, clutter is many, to high-order The interference of harmonic wave is big, it is preferable that the long h in chamber of coaxial resonant cavity 10 is more than exradius and the inner circle half of described cavity 19 annulus post Footpath sum.

Preferably, described coaxial resonant cavity 10 farther includes the most sheathed inner wire 11 and outer conductor 12, described interior Conductor 11 includes cylinder body 111, and it is away from one end of slide block 124, namely the end face bottom cavity 19 forms one Individual tip, offers a hole 125 bottom described cavity 19, described tip is stretched out from this hole 125 and i.e. formed probe 113 cavity.Institute The outer wall stating inner wire 11 i.e. forms the internal circular surfaces of described cavity 19 circle ring column.Described outer conductor 12 is ducted body, in it Wall i.e. forms the outer round surface of described cavity 19 circle ring column.Namely the inwall of the outer wall of described inner wire 11 and outer conductor 12 it Between form described cavity 19.By arranging independence and the inner wire 11 being coaxially disposed and outer conductor 12, can be the most internal Conductor 11 and outer conductor 12 are replaced respectively, thus change exradius and the inner circle radius of described cavity 19 circle ring column. As shown in Figure 2, the radius of described inner wire main body 111 is the radius a of inner wire 11, and the radius a of inner wire 11 is The circle ring column inner circle radius of described cavity 19.Preferably, arranged between described inner wire main body 111 and described probe 113 The section of crossing 112, the setting of described changeover portion 112 can ensure that the junction microwave propagation of inner wire main body 111 and described probe 113 Stable.Concrete, described changeover portion 112 be the frustum of a cone, end face that this frustum of a cone area is bigger and the end face of inner wire main body 111 It is connected, the end face that area is less arranges described probe 113.Simple in construction, microwave propagation good stability are so set.In described Conductor 11 can be integrated；Can also be Split type structure, as detachable in probe 113, can be replaced.

The shape of described outer conductor 12 can be any one in the shapes such as square, cuboid or cylinder, at this not Restricted.Only need to meet its hollow space is cylinder so that form circle between inwall and inner wire 11 outer wall of outer conductor 12 The cavity 19 of ring cylinder.

Preferably, as shown in fig. 1, described outer conductor 12 in hollow circular cylinder, one end of described outer conductor 12, i.e. cavity 19 open tops form an opening 121, and the other end i.e. cavity 19 bottom lock forms a blind end 123.It is to say, it is described Outer conductor 12 includes cylindrical outer wall 122, opening 121 and a blind end 123.Described slide block 124 be arranged on described outside In conductor 12, can move axially along outer conductor 12, the shape of described slide block 124 matches with cylindrical outer wall 122, i.e. to described Opening 121 is formed to be closed.Described inner wire main body 111 stretches out described slide block 124, on slide block 124 away from one end of probe 113 Offer the through hole (not shown) stretched out for described inner wire main body 111.The radius of described cylindrical outer wall 122 is outer conductor The radius b of 12, and the radius b of outer conductor 12 is the circle ring column exradius of described cavity 19.

Refer to Fig. 4, it is preferable that the opening 121 of described outer conductor 12 is provided with the first end cap 17, and described actuator 21 is solid It is scheduled on the first end cap 17, the stability in the large of described coaxial resonant cavity 10 can be improved by arranging the first end cap 17.Preferably, As it is shown on figure 3, described blind end 123 is embedded with shading ring 126 at hole 125, described shading ring 126 is around probe 113.Preferably , described shading ring 126 is made up of white stone, and shield effectiveness is good.

In the cavity 19 of described coaxial resonant cavity 10 provided by the present invention, coupling mechanism 14 microwave encouraged is with letter Single TEM ripple (Transverse Electric and Magnetic Field) circulation way is propagated.Described coupling machine Structure 14 can be coupling probe, coupling ring or coupling aperture.Wherein, coupling probe is electric coupling；Coupling ring is magnetic coupling；Coupling Hole is diffraction coupling, and different according to coupling aperture position, the coupled modes of coupling aperture can be single electric coupling or magnetic coupling, also Can be electricity, magnetic coupling exists simultaneously.

Preferably, described coupling mechanism 14 is coupling ring, and coupled modes are single magnetic coupling, and microwave is at coaxial resonant cavity In 10, the analysis of transmission is simpler.So strong near magnetic field, slide block 124 one end in cavity 19 and electric field is the most weak, micro-in cavity 19 Ripple is with the circulation way of TEM through 1/4 all after date, and magnetic field becomes the most weak and electric field reaches the strongest.Therefore by mobile slide block 124, i.e. change the long h in chamber so that the long h in chamber is in cavity 19 the 1/4 of microwave wavelength, and such microwave arrives the blind end of outer conductor 12 Just past 1/4 cycle when 123, electric field reaches the strongest, and is drawn outside described cavity 19 by probe 113 to form forceful electric power , the electric field intensity of this highfield can reach 10kV/cm.

Further, the present invention some preferably in embodiment, described coupling ring be arranged on described slide block 124 towards On the side of cavity 19, the side of described slide block 124 opposing coupler ring arranging joint 15, described joint 15 is used for connecting microwave Signal generation device (not shown) or microwave signal receiving device (not shown).That is microwave signal generator is by connecing 15 input the first microwave signal to coupling ring, utilize the magnetic coupling interaction of coupling ring to be converted to the second microwave signal and at cavity Transmission in 19, carries out coupling finally by coupling ring and forms the 3rd microwave signal output to a microwave signal receiver.Single Coupling ring can complete described first microwave signal to the conversion of described second microwave signal and transmission and described second microwave signal To conversion and the transmission of described 3rd microwave signal, the most described coupling ring can be one, it is also possible to is multiple.

In other preferred embodiment of the present invention, described coupling ring includes along described coaxial resonant cavity 10 axisymmetrical The first coupling ring 141 and the second coupling ring 142 arranged, is respectively used to input and the output of microwave signal, i.e. by the first coupling Cyclization 141 inputs coaxial resonant cavity 10, and resonant microwave signal produced by coaxial resonant cavity 10 is defeated by the second coupling ring 142 Go out.Agitate and coupling effect in being so effectively improved coaxial resonant cavity 10.As shown in Figure 2, the radius of described coupling ring is C, it is preferable that for avoiding the appearance of clutter in microwave signal, and ensure higher quality factor, described coupling ring radius and cavity The ratio of the circle ring column inner circle radius of 19, namely coupling ring radius is (0.5-1) with the ratio of inner wire 11 radius: 1, i.e. c/a For (0.5-1): 1.Optimum, the radius of described coupling ring is 0.5 with the ratio of inner wire radius, i.e. c/a=0.5.

Preferably, as shown in Figure 4, in described cavity 19, one end of close described probe 113 arranges dielectric layer 16, dielectric layer The shape of 16 matches with cavity 19, and described dielectric layer 16 is prepared by inorganic material, and the dielectric constant of this dielectric layer 16 is more than 1. The resonant frequency of coaxial resonant cavity 10 can be reduced by filled media layer 16, widen the resonant frequency of coaxial resonant cavity 10 further Scope.

For can reduce the resonant frequency of coaxial resonant cavity 10 by arranging dielectric layer 16, its principle is:

In coaxial resonant cavity 10, the microwave wavelength of transmission can be represented by velocity of wave and resonant frequency:

λ=v/f (1)

Wherein λ is wavelength, and v is velocity of wave, and f is resonant frequency.

Pass through wavelength during dielectric layer 16 during microwave transmission constant, then can get:

v₁/f₁=v₂/f₂ (2)

Wherein v₁、v₂For the velocity of wave forward and backward by dielectric layer 16, f₁、f₂For by the resonant frequency before and after dielectric layer 16. And by before dielectric layer 16, microwave transmits in atmosphere, v₁Can be represented by light velocity c；After dielectric layer 16, microwave is at dielectric layer Transmitting in 16, its velocity of wave is represented by:

v₂=c/n (3)

Wherein, n is refractive index.Owing to dielectric layer 16 is inorganic material, refractive index is represented by:

$n=\sqrt{{\mathrm{\μ\ϵ}}_1}---\left(4\right)$

Wherein, μ is the pcrmeability of dielectric layer 16, ε₁Dielectric constant for dielectric layer 16.Dielectric layer 16 is inorganic material, its Pcrmeability is approximately equal to 1, so taking μ=1.

Therefore, can obtain:

$f_2/f_1=1/\sqrt{{\mathrm{\ϵ}}_1}---\left(5\right)$

Owing to the dielectric constant of dielectric layer 16 is more than 1, i.e. DIELECTRIC CONSTANT ε₁More than 1, so f₂/f₁Less than 1, i.e. f₂It is less than f₁, reduce resonant frequency.

Preferably, as shown in Figure 4, the blind end 123 of described outer conductor 12 is dismountable second end cap 18, the most more Change dielectric layer 16, different resonant frequency range can be obtained.Preferably, described dielectric layer 16 is prepared by white stone, white stone Dielectric loss is little, it is ensured that obtain the coaxial resonant cavity 10 of higher figure of merit, as shown in Figure 5, the height of dielectric layer 16 For d.

Preferably, the height of dielectric layer 16 and the circle ring column inner circle radius of cavity 19, the namely height of dielectric layer 16 With inner wire 11 radius ratio be (1.5-2.5): 1, i.e. d/a are 1.5-2.5, so can effectively reduce the same of resonant frequency Time, it is ensured that higher quality factor.Wherein, optimum is the height circle ring column inner circle radius with cavity 19 of dielectric layer 16 Ratio be 2, i.e. d/a=2.

Hereinafter, using emulation testing, described emulation testing includes microwave signal test, resonant frequency test, quality factor Tests etc., verify restriction parameter concrete in coaxial resonant cavity 10 described above.

Coaxial resonant cavity 10 described above is verified.

1, the ratio of outer conductor 12 radius and the inner wire 11 radius impact on coaxial resonant cavity 10 harmonic wave

The ratio of described outer conductor 12 radius b and inner wire 11 radius a is n, and the coaxial resonant cavity 10 that n takes different value enters Row emulation testing, its result is as shown in Fig. 5, Fig. 6 and Fig. 7.

In Fig. 5, (a) is microwave signal curve during n=2.5, and spike is the resonance frequency that coaxial resonant cavity 10 screens Rate, and the peak shape of spike is the sharpest, shows that quality factor are the highest, recessed is then the frequency range being filtered off, and wherein R1, R2, R3 are respectively For first-harmonic, 3 order harmonicses and 5 order harmonicses；In Fig. 5, (b) is microwave signal curve during n=3.5；Micro-when (c) is n=5 in Fig. 5 Ripple signal curve；In Fig. 5, (c) is microwave signal curve during n=6.It can be seen that first-harmonic, 3 rank in microwave signal curve are humorous Involving 5 order harmonicses and be respectively formed spike, as n=2.5, the spike formed is more slow, shows that quality factor are relatively low, and as n=6 Clutter showed increased, the spike being formed required harmonic wave and first-harmonic, 3 order harmonicses and 5 order harmonicses forms interference.The most excellent Selection of land, the ratio n of outer conductor 12 radius b and inner wire 11 radius a takes 3.5 and 5.

Fig. 6 is the variation diagram that the resonant frequency of first-harmonic, 3 order harmonicses and 5 order harmonicses increases with n, wherein F1 correspondence first-harmonic, F2 Corresponding 3 order harmonicses, corresponding 5 order harmonicses of F3.It can be seen that facing to the increase of n, resonant frequency reduces therewith.Fig. 7 is first-harmonic, 3 rank The variation diagram that the quality factor of harmonic wave and 5 order harmonicses increase with n, wherein Q1 correspondence first-harmonic, corresponding 3 order harmonicses of Q2, corresponding 5 rank of Q3 Harmonic wave.It can be seen that along with the increase of outer conductor 12 radius b Yu the ratio n of inner wire 11 radius a, quality factor increase therewith.

Thus it is guaranteed that while quality factor are higher, obtain high resonant frequency, outer conductor 12 radius and inner wire 11 radius Ratio n preferably in the range of 3-5, optimum value is 4.

2, inner wire 11 radius impact on coaxial resonant cavity 10 harmonic wave

The coaxial resonant cavity 10 of different inner wire 11 radiuses is carried out emulation testing, and its result is as shown in Figure 8.

In Fig. 8, (a) is microwave signal curve during inner wire 11 radius a=2mm, and (b) is inner wire 11 radius a=3mm Time microwave signal curve, (c) is microwave signal curve during inner wire 11 radius a=4mm, and (d) is inner wire 11 radius a= Microwave signal curve during 5mm.

It can be seen that when inner wire 11 radius a is 2mm, first-harmonic, 3 order harmonicses and 5 order harmonicses form the peak shape of spike Good, quality factor are high, and clutter is minimum.And it is bent to contrast microwave signal corresponding when inner wire 11 radius a is 3mm, 4mm and 5mm Line, it is known that, the peak shape that its first-harmonic, 3 order harmonicses and 5 order harmonicses form spike is poor, and quality factor are relatively low, and clutter is more.

Therefore, for obtaining higher quality factor, inner wire 11 radius optimum is 2mm.

3, the chamber length impact on coaxial resonant cavity 10 harmonic wave

The regulation long h in chamber also carries out emulation testing to coaxial resonant cavity 10, and its result is as shown in Figure 9.

In Fig. 9, (a) is microwave signal curve during the long h=10mm in chamber, and (b) is that microwave signal during the long h=17mm in chamber is bent Line, (c) is microwave signal curve during the long h=24mm in chamber, and (d) is microwave signal curve during the long h=30mm in chamber.Can be seen that During the long h=10mm in chamber, form interference between spike, and along with the increase of the long h in chamber, resonant frequency reduces, the peak of formed spike Shape is good.

Concrete, when the scope of chamber length adjusts between 21-35mm, the resonant frequency of first-harmonic becomes between 2GHz-4GHz Change, the resonant frequency of 3 order harmonicses is to change between 6GHz-12GHz, and the resonant frequency of 5 order harmonicses is to become between 10GHz-20GHz Change.Therefore, when between chamber length is in the range of 21-35mm, the resonant frequency range of this corresponding coaxial resonant cavity 10 is 2GHz- 20GHz。

4, the height of dielectric layer 16 impact on coaxial resonant cavity 10 harmonic wave

To the coaxial resonant cavity 10 before arranging dielectric layer 16 and arrange differing heights dielectric layer 16 coaxial resonant cavity 10 and carry out Emulation testing, its result is as shown in figs. 10-12.

In Figure 10, (a) is the microwave signal curve of d=0mm, and (b) is the microwave signal curve of d=3mm, and (c) is d=9mm Microwave signal curve, (d) is the microwave signal curve of d=15mm.As seen from Figure 10, less as dielectric layer 16 height d Time, the higher clutter of resonant frequency is less；When dielectric layer 16 height d is bigger, resonant frequency is relatively low and clutter is more.

Figure 11 is the resonant frequency curve with dielectric layer 16 height change of first-harmonic, can find out intuitively, coaxial resonance The resonant frequency in chamber 10 reduces with the increase of dielectric layer 16 height.Figure 12 is the quality factor of first-harmonic are with dielectric layer 16 height The curve of change, be can be shown that by Figure 12 the quality factor of resonator cavity reduce with the increase of dielectric layer 16 height.

Therefore, from Figure 10-12 it can be seen that be the purpose reducing resonant frequency, and ensure higher quality factor, Dielectric layer 16 is highly preferred for 5mm.In this embodiment, used medium layer 16 is prepared by white stone, if selecting other material system Standby, need accordingly to adjust dielectric layer 16 height.

Visible in the present invention preferably embodiment, as material selection white stone and the dielectric layer 16 height d of dielectric layer 16 During for 5mm, the resonant frequency range of this coaxial resonant cavity 10 is 1GHz-20GHz.

5, the coupling ring radius impact on coaxial resonant cavity 10 harmonic wave

In coaxial resonant cavity 10, two coupling rings are set along axisymmetrical, the coaxial resonant cavity to different coupling ring radiuses 10 carry out emulation testing, and its result is as shown in figure 13.

In Figure 13, C1 is the microwave signal curve of coupling ring radius c=0.5mm, and C2 is the microwave of coupling ring radius c=1mm Signal curve, C2 is the microwave signal curve of c=1.5mm, and C4 is the microwave signal curve of c=2mm.

As seen from Figure 13, the change of coupling ring radius c on resonant frequency almost without impact.However as coupling ring half The reduction of footpath c, quality factor improve therewith.But when coupling ring radius c is 0.5, clutter occurs near first-harmonic.

Therefore, for ensureing higher quality factor and avoiding the appearance of clutter, it is preferable that coupling ring radius c is 1mm.

To sum up, the concrete structure for coaxial resonant cavity 10 carries out verifying and determining the embodiment of optimum.Concrete, interior Conductor 11 radius a is 2mm, and outer conductor 12 radius b is 8mm, and the range of accommodation of the long h in chamber is 21-35mm, and dielectric layer 16 is by white stone Preparing and height d is 5mm, coupling ring is provided with two and its radius is 1mm.The resonant frequency range of described coaxial resonant cavity 10 is 1GHz-20GHz, and quality factor are high.

Above-mentioned coaxial resonant cavity 10 is used for material dielectric constant test system 100, Microwave Nondestructive Testing device, wave filter and micro- Ripple sterilizing unit.

Concrete, second embodiment of the invention provides a kind of material dielectric constant test system 100

When the cavity 19 of coaxial resonant cavity 10 is constant, coaxial resonant cavity 10 have its fixing resonant frequency and quality because of Number, after placing sample, its resonant frequency and quality factor change, by the resonant frequency before and after change and quality factor Can calculate the electromagnetic properties such as the dielectric constant of sample, dielectric loss, electrical conductivity, pcrmeability, its medium dielectric constant microwave medium is particularly Important.

The test philosophy of 2.1 material dielectric constant test systems 100

The equivalent circuit of described coaxial resonant cavity 10 is RLC series circuit, i.e. such as part in dotted line frame in the left side in Figure 14, with Resonant frequency and the quality factor of axle resonator cavity 10 are represented by:

F=(LC)^-1/2/2π (6)

Q=(L/C)^1/2/R (7)

Wherein, f is resonant frequency, and Q is quality factor, and L is inductance, and C is electric capacity, and R is resistance.And electric capacity C is with the most humorous Shake chamber 10 cavity 19 size be correlated with, therefore also indicate that the radius of inner wire 11, the radius of outer conductor 12 and chamber length all can affect The resonant frequency of coaxial resonant cavity 10 and quality factor.The most in general, the side of reduction coaxial resonant cavity volume is generally used Formula, to obtain the coaxial resonant cavity 10 of high resonant frequency.

As shown in Figure 15, placing sample 31 at the needle point of described probe 113, sample 31 is positioned at the needle point of probe 113 In the electromagnetic field that place is formed, to the electromagnetic field formed is formed interference.In general, sample 31 is positioned at probe 113 place Axis on, and and probe 113 syringe needle between distance less than 3 μm, to ensure that sample 31 is positioned at the needle point place shape of probe 113 In the electromagnetic field become.

Due to the interference of sample 31, the equivalent circuit of coaxial resonant cavity 10 then becomes RLC equivalence in parallel from RLC series circuit Circuit, as shown in dotted line frame whole in Figure 14, its circuit introduced is i.e. such as part in the right dotted line frame in Figure 14.Therefore sample is placed After product, the electric capacity C and resistance R of equivalent circuit all change, resonant frequency f of coaxial resonant cavity 10 and quality factor q also phase That answers changes.

The electromagnetism of coaxial resonant cavity 10 resonant frequency f caused by sample 31 and the change of quality factor q and sample 31 Character is correlated with, and can be derived by perturbation theory.Perturbation is divided into two kinds, and one is slightly changed for whole chamber medium dielectric constant microwave medium, and two is chamber The change of dielectric constant is had and other Region Mediums do not change in the least region.Field amount before and after perturbation meets Mike respectively This Wei Fangcheng and boundary condition.

For having before perturbation:

$\begin{array}{c}\▿\×{\stackrel{\→}{E}}_0=-{\mathrm{j\ω}}_0{\mathrm{\μ}}_0{\stackrel{\→}{H}}_0---\left(8\right)\\ \▿\×{\stackrel{\→}{H}}_0={\mathrm{j\ω}}_0{\mathrm{\ϵ}}_0{\stackrel{\→}{E}}_0---\left(9\right)\\ \stackrel{\→}{n}\×{\stackrel{\→}{E}}_0=0---\left(10\right)\end{array}$

Wherein,For the electric field in coaxial resonant cavity before perturbation 10,For the magnetic field in coaxial resonant cavity before perturbation 10, ω₀For the resonant frequency in coaxial resonant cavity before perturbation 10, μ₀For the pcrmeability in coaxial resonant cavity before perturbation 10, ε₀For perturbation Dielectric constant in front coaxial resonant cavity 10,For the unit normal vector in coaxial resonant cavity 10.

For having after perturbation:

$\begin{array}{c}\▿\×{\stackrel{\→}{E}}_0=-j\mathrm{\ω}(\mathrm{\μ}+\mathrm{\Δ}\mathrm{\μ})\stackrel{\→}{H}---\left(11\right)\\ \▿\×\stackrel{\→}{H}=j\mathrm{\ω}(\mathrm{\ϵ}+\mathrm{\Δ}\mathrm{\ϵ})\stackrel{\→}{E}---\left(12\right)\\ \stackrel{\→}{n}\×\stackrel{\→}{E}=0---\left(13\right)\end{array}$

Wherein,For the electric field in coaxial resonant cavity after perturbation 10,For the magnetic field in coaxial resonant cavity after perturbation 10, ω For the resonant frequency in coaxial resonant cavity after perturbation 10, Δ μ is the incremental permeability that perturbation introduces, and Δ ε is Jie that perturbation introduces Electric constant increment.

Derivation is similar to cavity wall perturbation situation, can obtain:

$\frac{\mathrm{\ω}-{\mathrm{\ω}}_0}{{\mathrm{\ω}}_0}=-\frac{{\∫}_{\mathrm{\Δ}V}\left(\mathrm{\Δ}\mathrm{\ϵ}\right|E_0{|}^2+\mathrm{\Δ}\mathrm{\μ}\left|H_0{|}^2\right)dV}{{\∫}_V\left({\mathrm{\ϵ}}_0\right|E_0{|}^2+{\mathrm{\μ}}_0\left|H_0{|}^2\right)dV}=-\frac{{\∫}_{\mathrm{\Δ}V}\left(\mathrm{\Δ}\mathrm{\ϵ}\right|E_0{|}^2+\mathrm{\Δ}\mathrm{\μ}\left|H_0{|}^2\right)dV}{4W}---\left(14\right)$

Can be used to be calculated DIELECTRIC CONSTANT ε by above formula_rAnd magnetic permeability μ_r。

For lossy dielectric, above formula is still set up, but dielectric constant and resonant frequency are intended to bring into plural form:

μ=μ₀Δ μ=0 (15)

ε=ε₀(ε′-jε″) (16)

$\begin{array}{c}{\mathrm{\ω}}_0^{\′}={\mathrm{\ω}}_0+j\frac{{\mathrm{\ω}}_0}{2Q_0}---\left(17\right)\\ {\mathrm{\ω}}^{\′}=\mathrm{\ω}+j\frac{\mathrm{\ω}}{2Q}---\left(18\right)\end{array}$

Wherein, μ is the pcrmeability after perturbation in coaxial resonant cavity 10, and ε is that the dielectric in coaxial resonant cavity 10 is normal after perturbation Number, the real part that ε ' is DIELECTRIC CONSTANT ε, ε is " for the imaginary part of DIELECTRIC CONSTANT ε, Q₀For the quality in coaxial resonant cavity before perturbation 10 because of Number, Q is the quality factor after perturbation in coaxial resonant cavity 10.

Above formula is divided into two:

I.e. obtain dielectric constant and resonant frequency, the relation of quality factor.Visible, lossy dielectric real part causes resonant frequency Skew, imaginary part causes cavity quality factor to change.Therefore, before and after perturbation, namely sample 31 is for coaxial resonant cavity 10 Before and after carrying out perturbation, measured resonant frequency and quality factor, utilize formula (20), formula (21) that institute's test sample product can be calculated The dielectric constant of 31.

The concrete structure of 2.2 material dielectric constant test systems 100

Shown in Figure 15, Figure 16 and Fig. 1, this material dielectric constant test system 100 includes described coaxial resonant cavity 10 And control system 60, described control system 60 can complete the input of microwave signal, export and analyze.Described coaxial resonant cavity 10 Resonant frequency is the test frequency of described material dielectric constant test system；The resonant frequency range of coaxial resonant cavity 10 is The test scope of described material dielectric constant test system；When the quality factor of described coaxial resonant cavity 10 are high and clutter is few, institute The test accuracy stating material dielectric constant test system is high.

Preferably, described control system 60 includes that Network Analyzer 40 and computer 50, described Network Analyzer 40 can be used In microwave signal input, export and analyze, microwave signal generating means that Network Analyzer 40 is the most described above or Microwave signal receiver；Described computer 50 can be used for providing man machine operation interface and controlling Network Analyzer 40, and logarithm According to carrying out being calculated the dielectric constant of material of being measured and monitored the growth of standing timber.

Concrete, described coaxial resonant cavity 10 is connected with Network Analyzer 40, described Network Analyzer 40 and computer 50 It is connected, controls Network Analyzer 40 by computer 50, and obtain data and the result that Network Analyzer 40 is analyzed.Due to The resonant frequency range width of described coaxial resonant cavity 10, the most described test system has the advantage of test wide frequency range, and Carried out the test of sample 31 by probe 113, test speed is fast.

Preferably, described material dielectric constant test system 100 also includes actuator 20, can regulate coaxial resonant cavity 10 Position between resonant frequency and coaxial resonant cavity 10 and sample 31.Described actuator 20 is controlled by computer 50, actuator 20 can be connected by cable with computer 50, it would however also be possible to employ radio connection, connect such as wireless network or bluetooth connects Connect.Concrete, described actuator 20 includes the first actuator 201, and the first actuator 201 is connected with actuator 21, can pass through Change the resonant frequency of chamber length regulation coaxial resonant cavity 10；Described actuator 20 farther includes the second actuator 202, and second adjusts Joint device 202 is connected with sample mounting table 30, can move print mounting table 30, thus adjust the position between sample 31 and probe 113 Put.

Preferably, the second actuator 202 is connected with movable block 23, and described movable block 23 can drive coaxial resonant cavity 10 along axle To movement, z-axis moves the most as shown in Figure 14.And described sample mounting table 30 is moving in axially vertical plane, i.e. exist Move along x-axis, y-axis on x/y plane.So can guarantee that position adjustment between coaxial resonant cavity 10 and sample 31 rapidity and Accuracy.

Preferably, as shown in figure 17, described sample 31 can be combined sample, including some subsamples 32.Described subsample 32 array arrangements, by mobile example mounting table 30, make different subsamples 32 be positioned at the electricity formed at the needle point of probe 113 In magnetic field.So can quickly all subsamples 32 be tested, it is achieved material high flux is tested.And the dielectric due to material Frequency when constant and test is closely related, say, that at different frequencies, is tested the dielectric of the subsample 32 obtained Constant is the most different.Therefore use the coaxial resonant cavity 10 provided in embodiment one, the frequency model of 1-20GHz can be covered comprehensively Enclose, it is provided that more comprehensive and accurate test data, be suitable for the screening operation of lot of materials.

From formula (20), formula (21), need to utilize during calculating the resonant frequency of coaxial resonant cavity 10 before perturbation and quality because of Number.Owing to the resonant frequency under coaxial resonant cavity 10 cavity and quality factor are fixed value, it is preferred that described dielectric material When constant test system 100 also includes the cavity state that data base, described data base are coaxial resonant cavity 10, i.e. do not place sample Carry out the data acquisition system before perturbation.I.e. when coaxial resonant cavity 10 different cavity length, different medium layer 16 and dielectric layer 16 height, institute is right First-harmonic, 3 order harmonicses and the resonant frequency of 5 order harmonicses answered and quality factor.Resonance after the most directly sample 32 is placed in test Frequency and quality factor, resonant frequency and quality factor under cavity state then directly transfer from data base, can be effective Accelerate test speed, improve testing efficiency.

Additionally, due to the dielectric constant of material is different under different frequency, need when material is tested to consider that it is used On the way, and pointedly material dielectric constant under a certain specific frequency is tested.Therefore data base can be utilized, it is simple to resonance The quick setting of chamber resonant frequency, can test targetedly, improve testing efficiency.

Set up the flow chart of data base as shown in figure 18, comprise the following steps:

Step S1: record chamber length and medium layer information.I.e. by current chamber length and medium layer information under computer recording, Medium layer information is dielectric layer material and height thereof.

Step S2: carry out sweep check and obtain resonant frequency and quality factor.Carry out frequency sweep by Network Analyzer to obtain First-harmonic, 3 order harmonicses and the resonant frequency of 5 order harmonicses and quality factor, measured information is sent to calculate by Network Analyzer Machine.

Step S3: resonant frequency sweep check obtained and quality factor carry out record, and with the chamber length recorded and Medium layer information is corresponding.Resonant frequency measured by step S2 and quality factor are carried out record, and and step by i.e. computer The chamber length that S1 is recorded is corresponding with medium layer information.

Step S4: regulation chamber length or replacing dielectric layer.Chamber length and dielectric layer to coaxial resonant cavity are adjusted, to carry out The test of next group.

Step S5: repeat step S1-S4 and store data.I.e. repeat the above steps store data, the data stored When being different cavity length, different medium layer material and dielectric layer height, corresponding first-harmonic, 3 order harmonicses and the resonance of 5 order harmonicses All data of gained are carried out storing and i.e. form described data base by frequency and quality factor.

2.3 method of testings based on material dielectric constant test system 100

Should comprise the following steps based on the method for testing of material dielectric constant test system 100:

Step T1: resonant frequency during acquisition coaxial resonant cavity cavity and quality factor.I.e. obtain before placing sample coaxial The resonant frequency of resonator cavity and quality factor, it includes first-harmonic, 3 order harmonicses and the resonant frequency of 5 order harmonicses and quality factor.

When described material dielectric constant test system includes described data base, computer is according to current chamber length and medium Layer information, computer can the resonant frequency of coaxial resonant cavity and quality factor under extracting directly cavity state, improve survey further Examination speed and testing efficiency；Coaxial resonant cavity under cavity state can certainly be carried out sweep check, obtain resonant frequency And quality factor.

Step T2: place sample.Will put to the probe of coaxial resonant cavity by sample so that it is be positioned at the needle point place of probe In the electromagnetic field formed.If combined sample, by computer transmission regulating command to actuator, by actuator by difference Sample moves to the needle point of probe, and is positioned in the electromagnetic field formed at needle point.So can quickly and orderly to all sons Sample is tested.

Step T3: carry out sweep check, obtains placing resonant frequency and the quality factor of coaxial resonant cavity after sample.The most logical Cross Network Analyzer to carry out frequency sweep and obtain first-harmonic, 3 order harmonicses and the resonant frequency of 5 order harmonicses and quality factor, Network Analyzer Measured information is sent to computer.

Step T4: the dielectric placing the resonant frequency before and after sample and quality factor calculating sample according to coaxial resonant cavity is normal Number.Namely utilize resonant frequency and the quality factor of coaxial resonant cavity under the cavity state that step T1 obtains, and step T3 is surveyed Try resonant frequency and the quality factor obtained, be calculated the dielectric constant of sample by formula (20), formula (21).

When needing the dielectric constant testing sample under multiple frequency, this method of testing also includes step T5: adjust chamber long Or replacing dielectric layer.In general, adjust chamber length more convenient quickly, and change dielectric layer and be further intended to reduce resonance frequency Rate.After completing step T5, repeat step T1-T4, so can obtain the dielectric constant of sample under different frequency.Certainly need to measure Under assigned frequency during the dielectric constant of sample, chamber length when data base only need to be utilized to obtain this assigned frequency and medium layer information, The information obtained according to data base adjusts chamber length or changes dielectric layer, carries out step T1-T4 and i.e. can obtain sample under this assigned frequency The dielectric constant of product.

Described material dielectric constant test system 100 and method of testing have the advantage that

(1) this material dielectric constant test system 100 and method of testing only need to test the resonant frequency of coaxial resonant cavity 10 And quality factor, the dielectric constant that i.e. can get sample is then calculated by two formula, data process simple, testing efficiency High.

(2) this material dielectric constant test system 100 and method of testing are swept by the probe 113 of coaxial resonant cavity 10 Retouch formula detection, testing sample only need to be positioned over probe in the outer electromagnetic field formed of cavity.Can be mobile coaxial Resonator cavity thus drive probe so that testing sample is positioned in the electromagnetic field that probe is formed；Can certainly directly change and treat Test sample product so that it is be positioned in the electromagnetic field that probe is formed.Owing to testing sample is positioned at outside the cavity of coaxial resonant cavity, operation is just Prompt quick, it is effectively improved test speed, a large amount of sample can be tested at short notice, it is possible to achieve material high flux is tested.

Preferably, described cavity is circle ring column, and the exradius of this circle ring column is (3-5) with the ratio of inner circle radius: 1.When the exradius of circle ring column is (3-5) with the ratio of inner circle radius: when 1, the high-order harmonic wave of described coaxial resonant cavity, such as three The neighbouring clutter of order harmonics and five order harmonicses is few, and high-order harmonic wave has higher quality factor, can guarantee that the accuracy of test. And the resonant frequency of high-order harmonic wave is about the resonance of first-harmonic apparently higher than first-harmonic, the such as resonant frequency of three order harmonicses and five order harmonicses Three times of frequency and five times.

Therefore, this material dielectric constant test system 100 and method of testing test the most i.e. can get sample under three frequencies The dielectric constant of product 31, specifically first-harmonic, 3 order harmonicses and the test result of three frequency test points corresponding to 5 order harmonicses.This Sample not only improves testing efficiency, and test point is distributed more widely, just can substantially understand institute in the range of test through once test The situation of change of test sample product 31 dielectric constant.

Preferably, when described material dielectric constant test system 100 farther includes described data base, described dielectric material Constant test system 100 and method of testing, can improve test speed and testing efficiency further.

Preferably, cavity 19 height adjustable of described coaxial resonant cavity 10, the height of described cavity 19 is more than described cavity The exradius of 19 annulus posts and inner circle radius sum.When regulating the height of cavity 19, the resonant frequency of coaxial resonant cavity 10 is also Changing therewith, its excursion is the resonant frequency range of described coaxial resonant cavity 10.When being therefore changed without testing sample 31, By regulation cavity 19 height, can record in this resonant frequency range, Jie corresponding to the described each resonant frequency of testing sample 31 Electric constant.That is can grasp the testing sample 31 concrete numerical value with frequency change dielectric constant, it is simple to judge the most comprehensively This testing sample 31 application in microwave technical field.And control described cavity 19 circle ring column exradius with The ratio of the inner circle radius of circle ring column is (3-5): 1, the resonant frequency of coaxial resonant cavity 10 is high, therefore this coaxial resonant cavity 10 Resonant frequency range width.And exradius and the inner circle half of described cavity 19 annulus post it is more than by controlling the height of cavity 19 Footpath sum, it is to avoid clutter occurs, it is ensured that test accuracy near high-order harmonic wave.

This material dielectric constant test system 100 and method testing scope are the resonant frequency of coaxial resonant cavity 10 Scope, and the resonant frequency range width of this coaxial resonant cavity 10, therefore this material dielectric constant test system 100 and the survey of method Examination scope is big.

Therefore, described material dielectric constant test system 100 and method have that testing efficiency is high, speed fast, test scope Big and that test accuracy is high advantage, is suitable for high flux test.

Specifically, third embodiment of the invention provides a kind of Microwave Nondestructive Testing device

The present invention also provides for a kind of Microwave Nondestructive Testing device, and it uses the coaxial resonant cavity that the present invention provides.Utilize described same Axle resonator cavity, places sample at the needle point of its probe, test speed is fast.Sample can change coaxial resonance with the interaction of needle point The resonant frequency in chamber and quality factor, can complete detection by the resonant frequency of coaxial resonant cavity and the change of quality factor. And due to microwave good directionality, run through dielectric material ability strong, but can not penetrating metal and the preferable material of electric conductivity. Whether the inside that therefore can detect sample is damaged, and by measurement data, obtains the image of institute's test sample product internal structure, test Result accuracy is good.

The structure of the test system of Microwave Nondestructive Testing can be identical with material dielectric constant test system 100 in embodiment two, Only because principle is different, computer processing data and the process of calculating are inconsistent, the test that the most only computer is carried Software is different.

Specifically, fourth embodiment of the invention provides a kind of wave filter

The present invention also provides for a kind of wave filter, and it uses the coaxial resonant cavity 10 that the present invention provides.Described wave filter utilizes The effect of described coaxial resonant cavity 10 frequency-selecting realizes filtering, and the mid frequency of this wave filter is the resonance frequency of coaxial resonant cavity 10 Rate, its bandwidth is then determined by quality factor.Due to the resonant frequency range width of described coaxial resonant cavity 10, therefore there is frequency model Enclose wide advantage.Long also by regulation chamber, change resonant frequency and the quality factor of coaxial resonant cavity 10, and then adjust filtering The mid frequency of device and bandwidth so that described wave filter has adjustability.Additionally, be also with in embodiment two data set up Storehouse, according to the reality demand to filter effect, by changing chamber length and dielectric layer resonant frequency and the bandwidth i.e. to this wave filter Accurately regulate.

Specifically, fifth embodiment of the invention provides a kind of microwave sterilizer

The present invention also provides for a kind of microwave sterilizer, and it uses the coaxial resonant cavity 10 that the present invention provides.Institute of the present invention There is provided and highfield at probe 113 needle point of coaxial resonant cavity 10, can be formed, utilize the highfield formed to can be used for sterilizing.

The principle of described microwave sterilizer is: apply electromagnetic field on cell membrane, when electromagnetic field intensity reaches kV/cm Magnitude, and the persistent period is between delicate and millisecond, i.e. duration ranges be 1-1000 delicate time, cell membrane electrical conductivity can be changed, Meanwhile, cell membrane there will be micropore, has been temporarily lost with its barrier function, so that inner material leaks, macromole is inhaled Receipts amount increases, here it is cell membrane " electroporation " phenomenon.According to applying the size of electric field intensity and can be divided into again action time can Inverse electroporation and irreversible electroporation.This phenomenon belongs to a kind of biophysical phenomena, and its advantage effective percentage is high, without remaining poison Property, parameter are easy to control etc..

Concrete, coaxial resonant cavity 10 provided by the present invention, when using coupling ring 14 to be magnetically coupled, micro-in cavity 19 Ripple is with the circulation way of TEM through 1/4 all after date, and magnetic field becomes the most weak and electric field reaches the strongest.I.e. by mobile slide block 124, namely change chamber long so that the 1/4 of the microwave signal wavelength of a length of input in chamber, or change the microwave signal of input Wavelength so that it is wavelength is 4 times of chamber length, all enables to blind end 123 electric field of outer conductor 12 and reaches the strongest, and by visiting Pin 113 is drawn and is formed highfield outside chamber, and its electric field intensity can reach 10kV/cm, and bactericidal effect is good.

Compared with prior art, a kind of material dielectric constant test system provided by the present invention, it includes coaxial resonance Chamber and control system；Described coaxial resonant cavity includes cavity and stretches out the probe of cavity；Described control system is used for providing coaxial The microwave input signal of resonator cavity, described probe forms electromagnetic field outside described cavity, and testing sample is by this electromagnetic field Disturb thus change the microwave output signal of described coaxial resonant cavity；Described control system is additionally operable to analyze the micro-of coaxial resonant cavity Wave output signal；Described control system is treated by being analyzed being calculated to the microwave output signal before and after placement testing sample The dielectric constant of test sample product.This material dielectric constant test system only need to test the resonant frequency of coaxial resonant cavity and quality because of Number, then calculates the dielectric constant that i.e. can get sample by two formula, and data process simple, and testing efficiency is high.And should Material dielectric constant test system is scanned formula by the probe of coaxial resonant cavity and detects, and only testing sample need to be positioned over spy Pin is in the outer electromagnetic field formed of cavity.Can be mobile coaxial resonant cavity thus drive probe so that testing sample It is positioned in the electromagnetic field that probe is formed；Can certainly directly change testing sample so that it is be positioned at the electromagnetism that probe is formed In Chang.Owing to testing sample is positioned at outside the cavity of coaxial resonant cavity, simple operation is quick, is effectively improved test speed, can be short The a large amount of sample of time build-in test, it is possible to achieve material high flux is tested.

Further, described cavity is circle ring column, and the exradius of this circle ring column is (3-with the ratio of inner circle radius 5): 1.When the exradius of circle ring column is (3-5) with the ratio of inner circle radius: when 1, the high-order harmonic wave of described coaxial resonant cavity, Neighbouring clutter such as three order harmonicses and five order harmonicses is few, and high-order harmonic wave has higher quality factor, can guarantee that the standard of test Really property.And the resonant frequency of high-order harmonic wave is about first-harmonic apparently higher than first-harmonic, the resonant frequency such as three order harmonicses and five order harmonicses Three times and five times of resonant frequency.Therefore, under this material dielectric constant test system and test the most i.e. can get three frequencies The dielectric constant of sample, specifically first-harmonic, 3 order harmonicses and the test result of three frequency test points corresponding to 5 order harmonicses.This Sample not only improves testing efficiency, and test point is distributed more widely, just can substantially understand institute in the range of test through once test Survey the situation of change of sample permittivity.

Further, described material dielectric constant test system also includes that data base, described data base are coaxial resonance Data acquisition system during the cavity state of chamber, can improve test speed and testing efficiency further.

Further, described material dielectric constant test system also includes actuator and sample mounting table, described sample Mounting table is used for placing sample；Described actuator can quickly regulate described sample mounting table and the position of described coaxial resonant cavity, When testing with realization many groups sample, probe can be made quickly to determine with the position of testing sample, it is thus possible to improve material further The test speed of material dielectric constant test system.

Further, described actuator control described coaxial resonant cavity be axially moveable, described sample mounting table with Move in axially vertical plane.So can regulate the position between coaxial resonant cavity and sample quickly and accurately, it is ensured that material The rapidity of dielectric constant test system and accuracy.

Further, the height adjustable of described cavity, the height of described cavity is more than circle ring column exradius and circle Ring cylinder inner circle radius sum.When regulating the height of cavity, the resonant frequency of coaxial resonant cavity changes the most therewith, its excursion It is the resonant frequency range of described coaxial resonant cavity.When being therefore changed without testing sample, by regulation housing depth, can record Dielectric constant in this resonant frequency range, corresponding to each resonant frequency of described testing sample.That is can slap the most comprehensively Hold the testing sample concrete numerical value with frequency change dielectric constant, it is simple to judge this testing sample answering in microwave technical field With.And the exradius of circle ring column controlling described cavity is (3-5) with the ratio of the inner circle radius of circle ring column: 1, with The resonant frequency of axle resonator cavity is high, the therefore resonant frequency range width of this coaxial resonant cavity.And by controlling the height of cavity Exradius and inner circle radius sum more than described cavity annulus post, it is to avoid clutter occurs, it is ensured that test near high-order harmonic wave Accuracy.

Further, in described cavity, the one end near described probe arranges dielectric layer, the shape of dielectric layer and cavity Match；Described dielectric layer is prepared by white stone, and its dielectric constant is more than 1, the height of described dielectric layer and the annulus post of cavity Internal radius of circle ratio be (1.5-2.5): 1.The resonant frequency of coaxial resonant cavity can be reduced, further by arranging dielectric layer Widen the resonant frequency range of coaxial resonant cavity, i.e. widen the test scope of material dielectric constant test system.And given an account of Matter layer is prepared by white stone, the circle ring column inner circle radius of the height of dielectric layer and cavity ratio be (1.5-2.5): 1, so While effectively reducing resonant frequency, it is ensured that higher quality factor, namely widen material dielectric constant test system While test scope, it is ensured that test accuracy.

Further, described coaxial resonant cavity includes the coupling mechanism being connected with control system, described coupling mechanism bag Including at least one coupling ring, the radius of described coupling ring is (0.5-1) with the ratio of the circle ring column inner circle radius of cavity: 1.So energy Avoid the appearance of clutter in microwave signal, and ensure higher quality factor, namely ensure material dielectric constant test system Test accuracy.

Compared with prior art, the present invention also provides for a kind of test side based on above-mentioned material dielectric constant test system Method, comprises the following steps: resonant frequency during acquisition coaxial resonant cavity cavity and quality factor；Place sample；Carry out frequency sweep survey Examination, obtains placing resonant frequency and the quality factor of coaxial resonant cavity after sample；Before and after placing sample according to coaxial resonant cavity Resonant frequency and quality factor calculate the dielectric constant of sample.This material dielectric constant method of testing step is few, data process letter List and sample replacing are quick and convenient fast, therefore have the advantage that test speed is fast, testing efficiency is high.

Further, the step of resonant frequency during described acquisition coaxial resonant cavity cavity and quality factor is entered One step simplifies, i.e. resonant frequency and quality factor are obtained by a data base, and described data base is coaxial resonant cavity cavity state Time data acquisition system.So the testing time be can effectively reduce, test speed and testing efficiency improved further.

The foregoing is only presently preferred embodiments of the present invention, not in order to limit the present invention, all former in the present invention Any amendment made within then, within equivalent and improvement etc. all should comprise protection scope of the present invention.

Claims (10)

1. a material dielectric constant test system, including coaxial resonant cavity and control system；It is characterized in that: described the most humorous The chamber that shakes includes cavity and stretch out the probe of cavity；Described control system is for providing the microwave input signal of coaxial resonant cavity, institute Stating probe and form electromagnetic field outside described cavity, testing sample is by the interference to this electromagnetic field thus changes described coaxial resonance The microwave output signal in chamber；Described control system is additionally operable to analyze the microwave output signal of coaxial resonant cavity；Described control system By the microwave output signal before and after placement testing sample is analyzed being calculated the dielectric constant of testing sample.

2. material dielectric constant tests system as claimed in claim 1, it is characterised in that: described material dielectric constant test system Also include that actuator and sample mounting table, described sample mounting table are used for placing sample；Described actuator can regulate described sample Mounting table and the position of described coaxial resonant cavity.

3. material dielectric constant tests system as claimed in claim 2, it is characterised in that: described actuator controls described the most humorous The chamber that shakes is axially moveable, and described sample mounting table is moving in axially vertical plane.

4. material dielectric constant tests system as claimed in claim 1, it is characterised in that: described material dielectric constant test system Also include that data base, described data base are data acquisition system during coaxial resonant cavity cavity state.

5. material dielectric constant test system as according to any one of claim 1-4, it is characterised in that: described cavity is annulus Cylinder, the exradius of this circle ring column is (3-5) with the ratio of inner circle radius: 1.

6. material dielectric constant tests system as claimed in claim 5, it is characterised in that: the height adjustable of described cavity, described The height of cavity is more than circle ring column exradius and circle ring column inner circle radius sum.

7. material dielectric constant tests system as claimed in claim 5, it is characterised in that: near described probe in described cavity One end arranges dielectric layer, and the shape of dielectric layer matches with cavity；Described dielectric layer is prepared by white stone, and its dielectric constant is more than 1, the circle ring column inner circle radius of the height of described dielectric layer and cavity ratio be (1.5-2.5): 1.

8. material dielectric constant tests system as claimed in claim 5, it is characterised in that: described coaxial resonant cavity includes and controls The coupling mechanism that system is connected, described coupling mechanism includes at least one coupling ring, the radius of described coupling ring and the annulus of cavity The ratio of cylinder inner circle radius is (0.5-1): 1.

9. one kind based on material dielectric constant described in claim 1 test system method of testing, it is characterised in that: include with Lower step: resonant frequency during acquisition coaxial resonant cavity cavity and quality factor；Place sample；Carry out sweep check, put Put resonant frequency and the quality factor of coaxial resonant cavity after sample；According to coaxial resonant cavity place the resonant frequency before and after sample and Quality factor calculate the dielectric constant of sample.

10. material dielectric constant tests system as claimed in claim 9, it is characterised in that: during described coaxial resonant cavity cavity Resonant frequency and quality factor are obtained by a data base, set up described data base and comprise the following steps: record chamber length and medium Layer information；Carry out sweep check and obtain resonant frequency and quality factor；Record resonant frequency and quality factor；Sweep check is obtained To resonant frequency and quality factor carry out record, and corresponding with the chamber length recorded and medium layer information；Regulation chamber length or Change dielectric layer；Repeat abovementioned steps and store data.