JPS6022306B2 - Complex permittivity measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylindrical compact resonator with a cylindrical TEo, . There are some related to measurement devices used to determine dielectric constant and dielectric loss using modes.

The compound dielectric constant here refers to the dielectric constant.
This is the complex representation. A dielectric resonator is a cylindrical dielectric block whose axial length is equal to an integral multiple of a half wavelength of the frequency of electromagnetic waves, and which extends from both axial ends of the dielectric cylinder 2. It is a metal short circuit,
In order to propagate electromagnetic waves inside a dielectric block, they are usually coupled by magnetic field coupling. The electromagnetic waves in the dielectric part that are coupled by magnetic field coupling will be affected by the inherent permittivity of the dielectric flock.If the dielectric block is forged, for example, there is a large gap in the air, the electromagnetic waves will be reflected at the interface. It becomes a resonator, and many resonance modes are established depending on the coupling state. Among them, the cylinders TEo, . Coleman has already made it clear that permittivity and dielectric loss can be easily and accurately measured by utilizing the fact that the mode has only a circumferential component as an electric field component and the axial component is zero at the top and bottom surfaces of the sample. It was announced by Mr. triple. I.

Em. T. Vol. 8, P402 (1962)] Exact solutions can be easily obtained for the electromagnetic field equations inside and outside the cylindrical sample, the filling factor of the sample is close to 1 and the sensitivity is good, and this is caused by the air gap between the dielectric material and the shorting conductor. It currently holds a firm position as a method for measuring complex permittivity because there is no measurement error. However, this type of existing measuring device has a structure in which the input/output coupling part is fixed, making it impossible to freely change the degree of coupling and adjust the input/output power of the dielectric resonator to an appropriate level. There was a lack of ease and credibility. In order to eliminate such drawbacks, the present invention provides a first connecting portion.
The present invention provides an Enomoto dielectric constant measuring device in which the structure shown in the figure makes the coupling antenna movable, thereby making measurement extremely easy.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a cross-sectional view of a coupling section including a moving coupling antenna. 1 is a coupling antenna, one end of which is connected to the inner conductor of a coaxial cable indicated by 2, and the other end thereof to an outer conductor indicated by 4.

The outer diameter of the outer conductor 4 is thicker at a portion indicated by 5 than at other portions, and a groove 6 and a stopper 7 form an antenna 1 and a coaxial cable [consisting of an inner conductor 2, an outer conductor 4, and a Teflon 3]. ] is prevented from rotating. The antenna 1 can be moved in the horizontal direction in the drawing by rotating a rotary part 9 that engages and connects a threaded part 8 cut on the outside of the outer conductor 4. 10 is connected to metal plate terminals (14, 16 in FIG. 2) forming the dielectric resonator shown in FIG. 2, and serves as a guide for rotation of 9.

FIG. 2 shows a complex dielectric constant measuring device according to the present invention.

That is, this device consists of a dielectric cylinder 11 sandwiched between parallel metal plates 12 and 13 (the following conditions are required when determining the dimensions of the dielectric cylinder: the length in the axial direction is cut off by the TE dish mode). The space under the shell must be larger than the medium wavelength of the sample (because TEo mode resonance occurs when the sample is inserted, the space must be larger than the medium wavelength of the sample). The resonator, the metal plate terminals 14, 15, and the input/output coupling part [movable parts 16, 17 and coupling antennas 16', 16'] 7' shown in FIG. The cage length is the horizontal length of the parallel metal plates 12 and 13, and the inner loop of the tip is 4.80. 12
and 13 should theoretically have infinite width, but in reality they are limited to a finite size by 14 and 15.

However, by making the distance between 11 and 14 (or 15) more than twice the axial length of the cylindrical power transfer body 11, 1
The error due to 2 and 13 having finite sizes is eliminated. An embodiment of the present invention will be described below with reference to FIG.
The measurement sample is a barium titanate-based sintered body with an outer diameter of 10.7
1. A cylindrical piece with a length of 5.23 mm in the axial direction (corresponding to army 8 in Fig. 3) is used.

This material is placed in the center between the parallel metal plates 12 and j3 in FIG. Then, the coupling antenna wings 6', 17' move parallel to the parallel metal plates 12, 13, thereby coupling the electromagnetic fields of the external waveguide and the resonator. Coupling is measured as insertion loss (IL), which indicates the degree of coupling. As a result, IL
The relationship between (dB) and the distance from the coupling antennas 16', 17' to the material was approximately as follows. That is, the distance is i. 0, 1.3 1.7, 2.0 and 2.2 aside IL was 5, 1 stop 2Q 30 and 4 old respectively.

Figure 3 shows the degree of IL and Q when the degree of coupling is varied and measured by the complex dielectric constant measuring device according to the present invention.
An example of (QL) is shown below. Actual measured load Q (Q
L) and no-load Q (Q.

) is measured using this device as a transmission type resonator, and it is well known that ``At that time, if one half of the common logarithm of the ratio of the input power to the output power at resonance is expressed as IL.

In Figure 3, IL=2 is Q from the measured value of QL in the old time.

Seek that Q. The curve calculated using m formula and IL is 5
The actual measured values of QL for various values of B of ~4 are shown. The actual measured values and the calculated curve of equation '1' are in good agreement, and this shows that using the measuring device according to the present invention allows measurements to be made with the optimum degree of coupling to obtain output power convenient for measurement, making the measurement extremely easy. Systemically well measured. Figure 3 18'Mago' = 38. Fu÷=1.6xlo-4 material, 19'mago'=4o. &÷=1.5x cape material, 2 this amount'=46.
7,÷=4. The measurement results for the material of skin o-3 are shown.

When the above materials were measured using the method using the device of the present invention and when the antenna using the device of the present invention was fixed, each sample was subjected to 5 sub-measurements and compared. 20 (string) soil 0%, s
'=38.5±0.3%, please'-1.6×10-4±5
%, measurement time = 5.1 days, 19 materials IL = 20
(Ship) ±0%, 0.4%, ÷=1.5
xlo-4±6%, measurement time required, 20 materials are IL
= 20 (ship) officer 0%, 0% = 46.70 o. 5%, ÷=
4.5xlo-3%, measurement time required 5.19 days.

In the method of fixing the antenna, the material of 18 is IL = 20 ships) 1%, total ±〇. 35%, ÷=1.6±10%
, Measurement time required Mother's day, 19 materials are 1; 20 details) Soil 1
, 2%, go' = side seal. 42%, ÷-1.5×10-4×
12%, measurement time 6.1 days, 20 materials IL = 2
0 (calm) soil 1.5%, 0 = 46.7 ± 0.53%, ヱ ÷ = 4.5 x lo - 3 ± 8%, and the required time for measurement is 6.

From the above results, it can be said that the measuring method using the apparatus of the present invention has a small measurement error, a large saving in working time, and has great industrial merits.

Regardless of the structure of the above embodiments, even if the shape of the antenna changes, the plane of the antenna is kept perpendicular to the axis of the dielectric cylinder and is moved in the longitudinal direction of the dielectric cylinder. It is easy to think that the present invention is effective as long as it is a mechanism that makes it possible to make the excitation magnetic wave intensity of the dielectric resonator a desired intensity.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a coupling part with a moving antenna part;
The figure is a perspective view showing an embodiment of the Double Hata dielectric constant measuring device according to the present invention, and FIG. 3 is a diagram showing that measurements are performed correctly when the degree of coupling is changed. 1... Coupled antenna, 2... Internal conductor, 3
...Teflon, 4...External conductor, 6.
...Groove, 7...Stopper, 8...Screw part, 9...Rotating part, 11...Dielectric cylinder, 12
7 13... Metal plate, 14, 15... Metal plate terminal, 16, 17... Input/output coupling part, 16', 17'
・・・・・・Coupled antenna. O figure 2 figure O 3 figure

Claims (1)

[Claims] 1. In an apparatus for measuring the complex dielectric constant of the material of a dielectric resonator by measuring the resonant frequency and Q value of a cylindrical dielectric resonator, the coupling part with the external measurement circuit is equipped with a rotation mechanism, and the rotation mechanism is connected to the coupling part. It is possible to continuously move the surface of the loop-shaped antenna constituting the dielectric cylinder in the radial direction of the dielectric cylinder while keeping it perpendicular to the axis of the dielectric cylinder, thereby reducing the excitation electromagnetic wave intensity of the dielectric resonator. A complex dielectric constant measuring device characterized in that it is possible to obtain a desired intensity.