CN1120165A - Test method of non-metallic material microwave dielectric property and its application equipment - Google Patents

Abstract

In order to measure the microwave dielectric properties of non-metal material, a cut-off waveguide is especially designed, which couples via coupling hole with TE01n resonant cavity to constitute complex resonant cavity. Under the conditions that said cut-off waveguide contains or does not contain specimen, regulating piston makes resonance take place in the complex resonant cavity and two positions of piston and two Q factors of complex resonant cavity are recorded, which are put in a formula to find out the complex dielectric constant of the material. It is suitable for both low-dielectric-coefficient, low-loss material and high-dielectric-coefficient high-loss one.

Description

The method of testing of non-metallic material microwave dielectric properties and facilities and equipments thereof

The invention belongs to nonmetallic materials unit for electrical property parameters such as microwave complex dielectric constant, complex permeability method of testing and for implementing the custom-designed equipment of this method.

, mobile phone integrated, satellite communication, broadcasting, TV, radar, electronic countermeasure along with microwave, the application of microwave in worker, agricultural production process, the development in fields such as daily microwave and microwave biology, medical science, relate to from the semiconductor to the insulator, to nonmagnetic various types of materials, these material electric properties are widely different from magnetic.At present, press the material property difference, adopt the different measuring method of three classes: the Resonant-cavity Method that low-k, low-loss material is adopted various modes; High-k, low-loss material are adopted the dielectric resonant chamber method; The method that the magnetic or the nonmagnetic substance of lossy then adopted standing wave measurement line and microwave vector network analyzer.Therefore, required equipment and method of testing be more complicated all, use very inconvenient, the cost costliness.Thereby, require the cry of widely different method of energy measurement material electric property and equipment thereof more and more high.

The purpose of this invention is to provide a kind of method of testing and be to implement the custom-designed equipment of the method, can realize being applicable to simultaneously the measurement of the basic electromagnetic property of above-mentioned three class materials.

Before narration measuring method of the present invention, be illustrated as the organization plan of implementing this method equipment needed thereby earlier.This equipment comprises present widely used TE _O1nMode resonant cavity is the microwave frequency stabilization signal of 2-40GHZ by the 1 feed-in frequency of the microwave signal input port on this chamber, and its resonance signal is fed to resonance indicator from detectable signal delivery outlet 2.Design feature is at TE _O1nOne section cut-off waveguide 4 is installed on the cavity of mode resonant cavity 3, is laid measured material sample 5 (hereinafter to be referred as sample) in cut-off waveguide, cut-off waveguide is coupled to TE by coupling aperture 6 _O1nMode resonant cavity constitutes composite resonant cavity.Utilize TE _O1nThe high sensitivity of mould high Q resonant cavity is measured the material property in the cut-off waveguide.

The range of size of cut-off waveguide is as follows:

Cut-off waveguide length=25～50mm; Cut-off waveguide diameter and TE _O1nRatio=0.25 of mode resonant cavity cavity diameter～0.30; Coupling aperture equivalent area and TE _O1nThe ratio of mode resonant cavity cavity circular section=(3～5) * 10 ^-3

The drawing explanation:

Fig. 1 is the synoptic diagram of a kind of composite resonant cavity of designing of the present invention;

Fig. 2 is the synoptic diagram of the another kind of composite resonant cavity that designs of the present invention;

Fig. 3 is the A-A cut-open view of Fig. 1, Fig. 2.

Embodiment with reference to description of drawings present device scheme.

Example 1:

As shown in Figure 1, work as TE _O1nWhen microwave signal input port 1 on the cavity of mode resonant cavity 3 (hereinafter to be referred as cavity) and detectable signal delivery outlet 2 are located at cavity wall, one section copper cut-off waveguide 4 is fixed on the cavity top, coupling aperture 6 is located at the cut-off waveguide bottom, and measured material sample 5 is installed in the cut-off waveguide 4, TE _O1nThe tuning plunger 7 in chamber is mounted in the bottom of cavity.

Example 2:

As shown in Figure 2, when above-mentioned input port 1 and delivery outlet 2 were located at the cavity top, cut-off waveguide 4 freely was placed on the tuning plunger 7 of cavity bottom, and coupling aperture is located at the top of cut-off waveguide.

The coupling aperture shape is made up of four symmetrical strip holes (two ends in hole are arc), as shown in Figure 3

Measuring method of the present invention had both kept measuring at present the TE of low-k and low-loss material the best _O1nMode resonant cavity method measurement function is transformed again and expand, and sets up new method of testing, makes its electrical parameter or electromagnetics parameter of energy measurement high-k, low-loss material and absorbing material again.Promptly just can measure the widely different different materials of electric property with a kind of apparatus.

The principle of the inventive method: in the cut-off waveguide 4 that does not contain sample, except very little wall loss, do not have power to be absorbed, so it is actually net resistance by the impedance that coupling aperture 6 is incorporated into resonator cavity 3; Put into sample 5 when cut-off waveguide 4, part power is by absorption of sample, and sets up mirror field, produces a resistive component and reactance change.At this moment by the power reduction of coupling aperture 6 to cavity 3, resonator cavity produces the variation of corresponding Q factor reduction and resonance length.The size that sample leaves the distance of coupling aperture 6 of cut-off waveguide and coupling aperture 6 has determined the electric field vector in the sample 5, thereby has also determined the size of sample 5 power absorbed and reactance change.So to inserting the analysis of sample front and back resonator cavity 3 resonance behaviors in the cut-off waveguide 4, just can be about the information of measured material sample 5 electrical properties.

When in the cut-off waveguide during n.s., under certain angular frequency=2 π f conditions, the piston position reading L when recording resonance _oWith the Q factor Q _oWhen putting into thickness from coupling aperture S place and be the sample of d, above-mentioned analog value is L _f, Q _l, input impedance Z then _e=R _e+ jX _eTwo components be respectively:

Resistance $R_e={\left(\frac{{\mathrm{\λ}}_g}{{\mathrm{\λ}}_0}\right)}^2\frac{{\mathrm{\π}}^2{a}^2{\mathrm{f\μ}}_{0}l}{A}(\frac{1}{Q_i}-\frac{1}{Q_0}).....\left(1\right)$

Reactance $X_e=\frac{{\mathrm{\ω\μ}}_0}{{\mathrm{\α}}_0}-\frac{{\mathrm{\πa}}^2{\mathrm{\ω\μ}}_0}{A}(L_i-L_0)......\left(2\right)$

In the formula ${\mathrm{\α}}_0=\frac{2\mathrm{\π}}{{\mathrm{\λ}}_0}\sqrt{{\left(\frac{{\mathrm{\λ}}_0}{{\mathrm{\λ}}_c}\right)}^2-1},{\mathrm{\λ}}_c=2\mathrm{\πb}/3.832......\left(3\right)$ λ _c=cutoff wavelength; λ _g=waveguide wavelength; λ _o=free space wavelength; μ _o=permeability of vacuum; A=coupling aperture equivalent area; The 1=cavity length; A=resonator cavity radius; B=cut-off waveguide radius; α _oThe attenuation coefficient of=air interception waveguide; Angular frequency=2 π f (f is a frequency).

According to transmission line theory, can get the reflection coefficient ρ of air-medium interface _e=ρ _e'-j ρ _e" real part and imaginary part be: ${\mathrm{\ρ}}_e^{\′}=\frac{{{\mathrm{\α}}_0}^2({X_e}^2+{R_e}^2)-{\mathrm{\ω}}^2{{\mathrm{\μ}}_0}^2}{\exp (-2{\mathrm{\α}}_{0}S)[{R_e}^2{{\mathrm{\α}}_0}^2+{({\mathrm{\ω\μ}}_0+{\mathrm{\α}}_0{X}_e)}^2]}.....\left(4\right)$ ${\mathrm{\ρ}}_e^{\′\′}=\frac{2{\mathrm{\α}}_0{R}_e{\mathrm{\ω\μ}}_0}{\exp (-2{\mathrm{\α}}_{0}S)[{R_e}^2{{\mathrm{\α}}_0}^2+{({\mathrm{\ω\μ}}_0+{\mathrm{\α}}_0{X}_e)}^2]}.......\left(5\right)$

And the normalized impedance Z of air-medium interface (0)/Z ₁When this sample is arranged be: ${\left(\frac{Z\left(0\right)}{Z_1}\right)}_e=\frac{1+{\mathrm{\ρ}}_e}{1-{\mathrm{\ρ}}_e}=\frac{1+\frac{Z_1}{Z_1}\tanh 2\mathrm{\α}}{1+\frac{Z_1}{Z_2}\tanh 2\mathrm{\α}}......\left(6\right)$

Z in the formula ₁=j ω μ ₀/ α ₀, Z ₂=j ω μ ₀/ α; Tanh is the tangent of hyperbolic function; $\mathrm{\α}=j\frac{2\mathrm{\π}}{{\mathrm{\λ}}_0}\sqrt{{\mathrm{\ϵ}}_r-{\left(\frac{{\mathrm{\λ}}_0}{{\mathrm{\λ}}_c}\right)}^2}......\left(7\right)$ It is the multiple propagation factor that contains sample segments in the cut-off waveguide; ε _r=ε _r'-j ε _r"=ε _r' (1-jtan δ) is the relative complex permittivity of material; Here dielectric loss angle tangent tan δ=ε _r"/ε _r'.

Like this, with the complex reflection coefficient ρ that records _e, just can ask for the ε of nonmagnetic substance by process of iteration with computing machine _r' and tan δ.

For magnetic material, because of having $\mathrm{\α}=j\frac{2\mathrm{\π}}{{\mathrm{\λ}}_0}\sqrt{{\mathrm{\ϵ}}_r{\mathrm{\μ}}_r-{\left(\frac{{\mathrm{\λ}}_0}{{\mathrm{\λ}}_c}\right)}^2}......\left(8\right)$

Z ₂＝jωμ ₀μ _r/α (9) ${\mathrm{\μ}}_r=\left(\frac{\mathrm{\α}}{{\mathrm{\α}}_0}\right)/\left(\frac{Z_1}{Z_2}\right)......\left(10\right)$ μ in the formula _r=μ _r'-j μ _r" be the relative complex permeability of material.

So except that carrying out above-mentioned measurement, also the sample terminal short circuit will be measured once more piston reading L when obtaining to contain sample with above-mentioned same method step _kWith the Q factor Q _k, obtain R from formula (1)～(5) _k, X _kAnd ρ _k, obtain: ${\left(\frac{Z\left(0\right)}{Z_1}\right)}_k=\frac{1+{\mathrm{\ρ}}_k}{1-{\mathrm{\ρ}}_k}=\frac{Z_2}{Z_1}\tanh 2\mathrm{\α}.......\left(11\right)$

Find the solution the simultaneous equations that (6) and (11) are formed, ${\left(\frac{Z_1}{Z_2}\right)}^2=\frac{1+{\left(\frac{Z\left(0\right)}{Z_1}\right)}_k-{\left(\frac{Z\left(0\right)}{Z_1}\right)}_e}{{\left(\frac{Z\left(0\right)}{Z_1}\right)}_k{\left(\frac{Z\left(0\right)}{Z_1}\right)}_e}.....\left(12\right)$ Get α from formula (11) again, substitution formula (10) obtains plural μ _r, ask for ε from (8) formula again _r', promptly ${\mathrm{\ϵ}}_r=\frac{1}{{\mathrm{\μ}}_r}[{\left(\frac{{\mathrm{\λ}}_0}{{\mathrm{\λ}}_c}\right)}^2-\frac{{\mathrm{\α}}^2{\mathrm{\λ}}_0}{4{\mathrm{\π}}^2}].....\left(13\right)$

Method of testing of the present invention:

1. the equivalent area A of evaluation coupling aperture:

Under certain fixed frequency, in cut-off waveguide, do not contain and regulate resonator cavity under anything condition to resonance, piston reading L when reading resonance _oIn cut-off waveguide, put into the short circuit metal plate again, make it be close to coupling aperture 6, retune L _m, be calculated as follows A:

A＝πa ²α ₀(L _m-L ₀) (14)

2. to high-k (ε _rThe measurement of nonmagnetic substance＞10):

Microwave signal generator is adjusted to your required frequency, and when not containing sample in the cut-off waveguide, the piston of regulating composite resonant cavity is to resonance, and L takes reading _o, measure the Q factor Q _oPut into the sample that thickness is d in cut-off waveguide after, regulating piston recovery resonance records L again _i, Q _i, obtain R by formula (1), (2) _e, X _e, obtain ρ from formula (4), (5) _e=ρ _e'-j ρ _e", obtain the relative complex permittivity ε of material at last with Newton iteration method from formula (6), (7) _r=ε _r' (1-jtan δ).

When sample is close to coupling aperture (S=0), formula (4)～(7) obtain after merging simplification $\frac{X_e{\mathrm{\α}}_0-j{R}_e{\mathrm{\α}}_0}{{\mathrm{\ω\μ}}_0}=\frac{1+\sqrt{\frac{{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2-1}{{\mathrm{\ϵ}}_r-{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2}}\tan \frac{2\mathrm{\πd}}{{\mathrm{\λ}}_0}\sqrt{{\mathrm{\ϵ}}_r-{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2}}{1-\sqrt{\frac{{\mathrm{\ϵ}}_r-{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2}{{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2-1}}\tan \frac{2\mathrm{\πd}}{{\mathrm{\λ}}_0}\sqrt{{{\mathrm{\ϵ}}_r-({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2}}....\left(15\right)$

Can save intermediate parameters ρ like this _e, direct X from recording _eAnd R _eObtain plural ε by process of iteration _r

3. for the measurement of the lossy absorbing material of magnetic:

Microwave signal generator is adjusted to required frequency, when not containing sample in the cut-off waveguide, regulates composite resonant cavity to resonance, L takes reading _oWith measure the Q factor Q _oPut into the sample that thickness is d in cut-off waveguide after, regulating piston recovers resonance, records L _i, Q _iAgain the sample back is added the sheet metal short circuit, regulating piston recovers resonance once more, obtains L _kAnd Q _kWith Q _i, Q _oAnd L _i, L _oSubstitution formula (1), (2) get R _e, X _eAgain with L _kAnd Q _kSubstitute L _iAnd Q _iSubstitution formula (1), (2) obtain R _kAnd X _kTwo groups of R, X value substitution formula (4), (5) are got ρ _e=ρ _e'-j ρ _e" and ρ _k=ρ _k'-j ρ _k", its corresponding normalized impedance is ${\left(\frac{Z\left(0\right)}{Z_1}\right)}_i=\frac{1+{\mathrm{\ρ}}_i}{1-{\mathrm{\ρ}}_i}(i=e,k).....\left(15\right)$ Obtain Z from formula (12) ₁/ Z ₂

Then, can obtain multiple propagation factor α from formula (11).Just obtain the basic electromagnetic complex parameter ε of material so at last from formula (8), (10) and (13) _rμ _r, μ _rAnd ε _r

The advantage of the inventive method, except the widely different material of measurement performance, also have to sample cooperate with waveguide require low, promptly when sample diameter less than the cut-off waveguide diameter in 0.5mm the time, basically do not influence measurement result, unlike waveguide or coaxial test macro, sample must with their wringing fit.

Suitable frequency range of the present invention is 2～40GHz.

For understanding the inventive method result of use, under testing laboratory's condition, carry out practical operation, its result is as follows:

1. under 8～12GHz and 35GHz frequency condition, we are at the TE of internal diameter 2a=50mm _O1nBy Fig. 2 cut-off waveguide is installed on the single mode resonator cavity.The internal diameter 2b=15mm of cut-off waveguide, coupling aperture area A=6.03mm ², record material B aTi at frequency 9.375GHz ₄O ₉ε _r'=39.05, tan δ=0.69 * 10 ^-4

2. be 2～4GHz in frequency, we are at the TE of internal diameter 2a=180mm _O1nInstall cut-off waveguide by Fig. 1 on the chamber, internal diameter 2b=50mm, coupling aperture area A=120mm ², be that 4～8GHz is then at the TE of internal diameter 2a=120mm in frequency _O1nBy Fig. 1 cut-off waveguide internal diameter 2b=30mm, coupling aperture A=42mm are installed on the chamber ²Measurement contains the epoxy resin of carbonyl iron dust, and its result is: frequency f (GHz) ε _rμ _rμ _rε _r2.2 35.66-j12.30 2.99-j0.94 12.06-j0.352.8 30.67-j14.19 2.37-j1.13 12.86-j0.143.8 30.36-j14.67 2.41-j1.05 12.85-j0.515.1 25.40-j15.77 2.38-j1.29 11.02-j0.656.0 22.65-j16.57 2.02-j1.18 11.95-j1.257.1 21.13-j15.72 1.84-j1.23 11.92-j0.618.1 19.15-j15.12 1.62-j1.20 12.07-j0.37

Claims (7)

1. the method for testing of non-metallic material microwave dielectric properties is characterized in that, this method comprises the steps:

1) determines coupling aperture [6] equivalent area A

By the microwave signal of the given frequency of microwave signal mouth [1] feed-in, the tuning plunger [7] of regulating resonator cavity [3] makes resonator cavity reach resonance, tuning plunger position readings L when reading resonance _oIn cut-off waveguide [4], be adjacent to coupling aperture [6] and locate to be provided with a short circuit metal plate, readjust tuning plunger, read L _m, get coupling aperture equivalent area A by following formula:

A＝πa ²α ₀(L _m-L ₀) (14)

2) in cut-off waveguide [4], do not put into material sample [5], under given frequency, regulate tuning plunger and make composite resonant cavity reach resonance, write down tuning plunger position readings L this moment _o, and measure the Q factor values Q of composite resonant cavity _o

3) in cut-off waveguide, put into the material sample that thickness is d [5], regulate tuning plunger again, recover resonance and record corresponding L _iAnd Q _i

4) utilize by 2), 3) L that records of step _o, Q _oAnd L _i, Q _i, try to achieve the complex permittivity ε of material by formula _r

2. according to the method for testing of the non-metallic material microwave dielectric properties of claim 1, it is characterized in that for high-k (ε _r＞10) nonmagnetic substance comprises following method step:

1) with the L that measures _o, Q _oAnd L _i, Q _i, following two formulas of substitution are obtained resistance R _eWith reactance X _e: $R_e={\left(\frac{{\mathrm{\λ}}_g}{{\mathrm{\λ}}_0}\right)}^2\frac{{\mathrm{\π}}^2{a}^2{\mathrm{f\μ}}_{0}l}{A}(\frac{1}{Q_i}-\frac{1}{Q_0})......\left(1\right)$ $X_e=\frac{{\mathrm{\ω\μ}}_0}{{\mathrm{\α}}_0}-\frac{{\mathrm{\πa}}^2{\mathrm{\ω\μ}}_0}{A}(L_i-L_0).....\left(2\right)$ In the formula: ${\mathrm{\α}}_0=\frac{2\mathrm{\π}}{{\mathrm{\λ}}_0}\sqrt{{\left(\frac{{\mathrm{\λ}}_0}{{\mathrm{\λ}}_c}\right)}^2-1},{\mathrm{\λ}}_c=2b/3.832.....\left(3\right)$

2) from formula ${\mathrm{\ρ}}_e^{\′}=\frac{{{\mathrm{\α}}_0}^2({X_e}^2+{R_e}^2)-{\mathrm{\ω}}^2{{\mathrm{\μ}}_0}^2}{\exp (-2{\mathrm{\α}}_{0}S)[{R_e}^2{{\mathrm{\α}}_0}^2+{({\mathrm{\ω\μ}}_0+{\mathrm{\α}}_0{X}_e)}^2]}...\left(4\right)$ ${\mathrm{\ρ}}_e^{\′\′}=\frac{2{\mathrm{\α}}_0{R}_e{\mathrm{\ω\μ}}_0}{\exp (-2{\mathrm{\α}}_{0}S)[{R_e}^2{{\mathrm{\α}}_0}^2+{({\mathrm{\ω\μ}}_0+{\mathrm{\α}}_0{X}_e)}^2]}.....\left(5\right)$ Try to achieve the reflection coefficient ρ of air-medium interface _e=ρ _e'-j ρ _e" real part and imaginary part;

3) from formula ${\left(\frac{Z\left(0\right)}{Z_1}\right)}_e=\frac{1+{\mathrm{\ρ}}_e}{1-{\mathrm{\ρ}}_e}=\frac{1+\frac{Z_2}{Z_1}\tanh 2\mathrm{\α}}{1+\frac{Z_1}{Z_2}\tanh 2\mathrm{\α}}......\left(6\right)$ And formula $\mathrm{\α}=j\frac{2}{{\mathrm{\λ}}_0}\sqrt{{\mathrm{\ϵ}}_r-{\left(\frac{{\mathrm{\λ}}_0}{{\mathrm{\λ}}_c}\right)}^2}......\left(7\right)$

With the complex reflection coefficient ρ that records _eTry to achieve the complex permittivity of nonmagnetic substance by process of iteration with computing machine by formula (6)

When material sample is close to coupling aperture and is S=0, can be directly from formula $\frac{X_e{\mathrm{\α}}_0-j{R}_e{\mathrm{\α}}_0}{{\mathrm{\ω\μ}}_0}=\frac{1+\sqrt{\frac{{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2-1}{{\mathrm{\ϵ}}_r-{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2}}\tan \frac{2\mathrm{\πd}}{{\mathrm{\λ}}_0}\sqrt{{\mathrm{\ϵ}}_r-{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2}}{1-\sqrt{\frac{{\mathrm{\ϵ}}_r-{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2}{{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2-1}\tan \frac{2\mathrm{\πd}}{{\mathrm{\λ}}_0}\sqrt{{\mathrm{\ϵ}}_r-{({\mathrm{\λ}}_0/{\mathrm{\λ}}_c)}^2}}}...\left(15\right)$ Try to achieve complex permittivity ε by process of iteration _r

3. according to the test mode of the non-metallic material microwave dielectric properties of claim 1, it is characterized in that lossy absorbing material, comprise following method step for magnetic:

1) with the tuning Q that tries to achieve of above-mentioned same method _o, L _o, Q _iAnd L _i

2) add in the material sample back sheet metal short circuit retune L _kAnd Q _kValue is earlier with Q _i, Q _oAnd L _i, L _oSubstitution above-mentioned (1) formula (2) formula gets R _e, X _eAgain with L _kAnd Q _kSubstitute L _iAnd Q _iSubstitution (1) formula and (2) formula get R _kAnd X _k,, get ρ with above-mentioned two groups of R, X value difference substitution above-mentioned (4) formula and (5) formula _e=ρ _e'-j ρ _e" and ρ _k=ρ _k'-j ρ _k", its normalized impedance is ${\left(\frac{Z\left(0\right)}{Z_1}\right)}_i=\frac{1+{\mathrm{\ρ}}_i}{1-{\mathrm{\ρ}}_i}(i=e,k).....\left(16\right)$

By formula ${\left(\frac{Z_1}{Z_2}\right)}^2=\frac{1+{\left(\frac{Z\left(0\right)}{Z_1}\right)}_k-{\left(\frac{Z\left(0\right)}{Z_1}\right)}_e}{{\left(\frac{Z\left(0\right)}{Z_1}\right)}_k{\left(\frac{Z\left(0\right)}{Z_1}\right)}_e}......\left(12\right)$ Try to achieve Z ₁/ Z ₂

Again from formula ${\left(\frac{Z\left(0\right)}{Z_1}\right)}_k=\frac{1+{\mathrm{\ρ}}_k}{1-{\mathrm{\ρ}}_k}=\frac{Z_2}{Z_1}\tanh 2\mathrm{\α}.......\left(11\right)$ Obtain α; At last from following two formulas ${\mathrm{\μ}}_r=\left(\frac{\mathrm{\α}}{{\mathrm{\α}}_0}\right)/\left(\frac{Z_1}{Z_2}\right)........\left(10\right)$ ${\mathrm{\ϵ}}_r=\frac{1}{{\mathrm{\μ}}_r}[{\left(\frac{{\mathrm{\λ}}_0}{{\mathrm{\λ}}_c}\right)}^2-\frac{{\mathrm{\α}}^2{\mathrm{\λ}}_0}{4{\mathrm{\π}}^2}].....\left(13\right)$ Get μ respectively _rAnd ε _r

4. for implementing the equipment of the described non-metallic material microwave dielectric properties of claim 1 method of testing, comprise TE _O1nMode resonant cavity is 2-40GH by microwave signal input port [1] feed-in frequency ₂Microwave frequency stabilization signal, its resonance signal is fed to resonance indicator from detectable signal delivery outlet [2], it is characterized in that at TE _O1nOne section cut-off waveguide [4] is installed on the cavity of mode resonant cavity [3], is laid measured material sample [5] in cut-off waveguide, cut-off waveguide is coupled to TE by coupling aperture [6] _O1nMode resonant cavity constitutes composite resonant cavity.

5. equipment according to claim 4, it is characterized in that cut-off waveguide [4] range of size and be shaped as: cut-off waveguide length=25～50mm; Cut-off waveguide diameter: cavity diameter=0.25～0.30; Coupling aperture equivalent area: cavity circular section=(3～5) * 10 ^-3The coupling aperture shape is made up of the strip hole (two ends in hole are arc) of four symmetries.

6. according to claim 4 or 5 described equipment, it is characterized in that working as TE _O1nThe microwave signal input port [1] of mode resonant cavity [3] and detectable signal delivery outlet [2] are when being located at cavity wall, and cut-off waveguide [4] is fixed on the cavity top, and coupling aperture [6] is located at the bottom of cut-off waveguide [4].

7. according to claim 4 or 5 described equipment, it is characterized in that working as TE _O1nThe microwave signal input port [1] of mode resonant cavity [3] and detectable signal delivery outlet [2] are located at the top of cavity [3], and cut-off waveguide [4] freely is placed on the tuning plunger [7] of cavity bottom, and coupling aperture [6] is located at the top of cut-off waveguide.

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