METHOD AND A DEVICE FOR MEASURING DIELECTRIC CHARACTERISTICS OF MATERIAL BODIES

• US 20100001747A1
• Filed: 08/07/2009
• Published: 01/07/2010
• Est. Priority Date: 02/14/2007
• Status: Active Grant

• Current Assignee: JOINT-STOCK COMPANY 'HIGH TECH'
• Original Assignee: JOINT-STOCK COMPANY 'HIGH TECH'
• Inventors: Turkovskyi, Ivan I.
• Granted Patent: US 7,868,627 B2
• Time in Patent Office: Days
• US Class Current: 324/702
• CPC Class Codes: G01N 22/00 Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more G01N3/00 - G01N17/00, G01N24/00 take precedence
• CPC Class Codes: G01R 27/06 Measuring reflection coefficients; Measuring standing-wave ratio

Abstract

The inventive method for measuring dielectric characteristics of material bodies consists in generating a microwave signal, in dividing said signal into reference and sounding signals, in irradiating a body with the microwave signal when a waveguide probe contacts a tested material, in receiving the reflected, reference and total signals and in detecting said signals. The irradiation is carried out by means of a waveguide wave, the propagation number of which in the free space of the waveguide probe, which is filled with a prism-shaped dielectric insert,—“[εk²]^0.5” is selected within a range from 1.0 to 1.07 the propagation number of the waveguide wave “[εk²−(mπ/b)²+(nπ/a)²]^0.5”, where ε is the specific inductive capacitivity of the material; a and b are the length and the width of the cross-section of a rectangular waveguide; m and n are integer numbers representing the indexes of propagation modes in the dielectric-filled waveguide and k is the propagation number of a used millimeter radiation for an empty free space k=2πv/c, where v is frequency and c is a speed of light in vacuum. A device for carrying out said method is also disclosed.

Claims

1-3. -3. (canceled)

4. A method for measuring dielectric characteristics of materials, comprising:

generating a super high frequency (SHF) signal,

dividing the SHF signal into a reference signal and a probe signal,

contacting the material with a rectangular waveguide comprising a prism-shaped dielectric insert,

irradiating the material with the SHF signal through the waveguide with a wave having a wave number in the free space of the waveguide with the prism-shaped dielectric insert equal to [ε

·

k²]^0.5 and selected between 1 times and 1.07 times the longitudinal wave number of the waveguide wave, [ε

·

k²−

(mπ

/b)²+(nπ

/a)²]^0.5,

receiving a reflected signal, a reference signal, and a combined signal, and

detecting the reflected signal, the reference signal, and the combined signal,

where ε

is a relative dielectric permittivity of the insert;

where a and b are a length and a width of the cross-section of the waveguide;

where m and n are integers and are orders of propagating modes in the dielectric-filled waveguide; and

where k is a wave number of millimeter-wavelength radiation for empty free space equal to k=2π

v/c, where v is the radiation frequency, and c is the speed of light in vacuum.

5. The method according to claim 4, further comprising tuning of phase difference between the reflected and the reference signals using a short-circuit waveguide, for example through contact of the end-face of the waveguide probe with a polished metal mirror.

6. The method according to claim 5, wherein the tuning of the phase difference between the reflected and the reference signals comprises contacting an end-face of the waveguide with a polished metal mirror.

7. A device for measuring dielectric characteristics of materials, comprising:

a super high frequency (SHF) generator comprising a first output,

a power splitter comprising an input, a first output, and a second output,

a first breaker comprising an output, a first input, and a second input,

a second breaker comprising an output, a first input, and a second input,

a circulator comprising an input, a first output, and a second output,

a rectangular waveguide probe,

a dielectric prism mounted within a cavity of a terminal section of the waveguide probe;

a summator comprising an output, a first input, and a second input,

a quadratic detector comprising an input and an output,

an amplifier for signals at a modulation frequency,

a synchronous detector comprising a first output,

an analog-to-digital converter (ADC), and

a visualization device,

wherein the first output of the SHF generator is connected with the input of the power splitter,

wherein the first output of the power splitter is connected with the first input of the first breaker,

wherein the second output of the power splitter is connected with the first input of the second breaker,

wherein the second input of the first breaker is connected with the first output of the synchronous detector,

wherein the second input of the second breaker is connected with the first output of the synchronous detector,

wherein the output of the first breaker is connected with the input of the circulator,

wherein the first output of the circulator is connected with the waveguide probe,

wherein the second output of the circulator is connected with the first input of the summator,

wherein the second input of the summator is connected with the output of the second breaker,

wherein the output of the summator is connected with the input of the quadratic detector,

wherein the output of the summator is serially connected with the amplifier, the synchronous detector, the ADC, and the visualization device,

wherein arc sin([ε

·

k²−

(mπ

/b)²−

(nπ

/a)²]^0.5/[ε

·

k²]^0.5)−

(2h+1)·

β

<

arc sin(1/√

ε

),

where ε

is the relative dielectric permittivity of the material of the prism,

where a and b are a length and a width of a cross-section of the waveguide probe,

where β

is an inclination angle of a face of the dielectric prism to an axis of the waveguide probe,

where m and n are integers and are orders of propagating modes of the dielectric-filled waveguide,

where h is an integer greater than zero,

where k is a wave number of millimeter-wavelength radiation for empty free space equal to k=2π

v/c, where v is the radiation frequency, and c is the speed of light in vacuum.