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Open Coaxial Resonator Type Microwave Dielectormeter
PATENT No.3691812
 A system component used a network analyzer |
 A system component used a synthesized sweep oscillator |
The technical article regarding the measurement principle of this system was presented in the IEEE Microwave Theory and Techniques.
R. Inoue, et al., "Data Analysis of the Extraction of Dielectric Properties From Insulating Substrates Utilizing the Evanescent Perturbation Method",IEEE Trans. Microwave Theory Tech., vol. 54,no. 2, pp. 522-532, Feb. 2006.
Features
- ■ Measurement using an evanescent mode of an open coaxial resonator
- If a sample material is placed on the probe, an evanescent electrical field leaks from the probe tip into the sample material. This electrical field changes with the dielectric properties of the material, which in turn changes the resonant frequency and the Q factor of the whole cavity. The dielectric properties are then calculated from the changed resonance.
- ■ Simple, accurate and non-destructive measurement
- The open resonator enables the easy placement of the sample, and a fast, accurate measurement of its dielectric properties.
- ■ Stable measurement
- A firm contact between sample and probe is obtained with a vacuum attachment.
Specification(Provisional Figures)
| Frequency | 0.8 to 18GHz |
|---|---|
| Frequency Point | 5 discrete frequency points or 1 point can be chosen |
| Measuring range | ε: 1-15 tanδ: 0.001-0.1 |
| Measurement Accuracy | ε: ±1% tanδ: ±5% |
| Sample shape | Arbitrary if there is a flat surface (A dimension of more than 10mm x 10mm x 0.5mm are required.) |
FAQ
- ■The general of the system
- 1. What is the open coaxial resonator type microwave dielectrometer?
- 2. What are the system components of the synthesized sweep oscillator type and the network analyzer type?
- 3. What is the difference between this system and the conventional system?
- 4. What is the tool to measure?
- 5. What is the measurement principle using this probe?
- 6. How good is the accuracy and what is important for accurate measurements?
- ■The general of the system
- 1. What is the open coaxial resonator type microwave dielectrometer?
The open coaxial resonator type microwave dielectrometer is the system which measures dielectric properties at microwave frequencies. This system has 2 types, which use either a synthesized sweep oscillator (an alternative to a network analyzer) or a network analyzer.
- 2. What are the system components of the synthesized sweep oscillator type and the network analyzer type?
The synthesized sweep oscillator type consists of an oscillator, which includes a microwave signal generator and a detector, a measurement probe, a customized software, and accessories. This is a low cost type because it does not have expensive measurement devices. The network analyzer type sets up with your network analyzer to use. It consists of a measurement probe, a customized software, and accessories.
(*Please see the movie titled "2.System Components" on the top page.)- 3. What is the difference between this system and the conventional system?
The strongest point of the microwave dielectrometer is its ease of use. This system enables fast and non-destructive measurement of dielectric materials, becasue the probe can handle materials of any shapes as long as there is one flat surface. In addition, the microwave dielectrometer has highly accurate measurement software. By simply placing the material on the surface of the probe, and following an easy step-by-step operation of the software wizard, the measurement is achieved complex dielectric properties very accurately and very simply. (*Please see the movies titled "1.AET Microwave Dielectrometer" and "4.Actual Measurement" on the top page.)
- 4. What is the tool to measure?
The tool to measure is a unique measurement probe called a "coaxial resonator". The measurement can be chosen at a five-point simultaneous measurement mode or single-frequency measurement mode.
Type1: 0.8/2.45/4.2/5.8/7.6GHz Type2: 1/3/5/7/9GHz
Type3: 2/6/10/14/18GHz
Choose the specific frequency from the "frequency setting" list.The probe can handle materials of any shapes as long as there is one flat surface. The measurement is achieved by simply placing the material on the surface of the probe. It is suitable to measure for various solid-state samples such as plastics, ceramics, various resin, liquid crystal polymer, connector, glass, and others.
(*Please see the movie titled "3.Open Coaxial Probe" on the top page.)- 5. What is the measurement principle using this probe?
If a sample material is placed on the probe, the evanecent electrical field leaks from the probe tip into the sample material. This electrical field changs with the dielectric properties of the material, which in turn changes the resonant frequency and the Q factor of the whole cavity. The dielectric properties (εr, tanδ）are then calculated from the changed resonance.
The result of 5-points simultaneous measurement
(*Please see the movie titled "3.Open Coaxial Probe" on the top page.)- 6. How good is the accuracy and what is important for accurate measurements?
The random error of the epsilon is estimated to be less than 1%, and the error of the tangent delta is less than 5%. The absolute accuracy will be confirmed by the reference materials. Two different materials are used as references. By calculating the relative difference between the measurement results of the references and a sample material, external error sources (eg.room temperature) are eliminated. Most important for accurate measurements is a firm contact between the sample material and the surface of the coaxial probe. Only a tiny gap might significantly change measurement results. Microwave Dielectrometer has a vacuum absorption attachment equipped on the probe tip. The sample contacts with the probe firmly and the stable and accurate measurement is possible.
(*Please see the movie titled "1.AET Microwave Dielectrometer" on the top page.)
- ■Materials to be tested
- 1.What are the requirements for the sample material?
The materials to be tested are required to have at least one flat and smooth surface (larger than 10mm x 10mm). The sample shape is arbitary and the sample dimension should be larger than 10mm x 10mm x 0.5mm. To measure thin film materials, the film have to be stacked to get a total thickness greater than 0.5mm.
- 2. What are the limitations of the dielectric properties?
This system can measure relative dielectric constants from 1 to 15, and the loss tangent from 0.001 to 0.1.
- 3. What is the reason of the limitation of the properties?
The evanecent field does not penetrate deep enough into high epsilon materials, which makes an accurate measurement of the dielectric constant difficult. For small loss tangent, the total loss of the probe is relatively higher than the conventional cavity resonator because of the leakage of the evanecent field. This is the main reason for the difficulty of measuring very small dielectric losses. We recommend the resonant cavity type microwave dielectrometer for the measurement of the sample with high epsilon and very small dielectric losses.
- 4. Is it possible to measure anisotropic materials?
The evanecent field vector is not uniform. Thus, the anisotropic properties can not be measured.
- 5. Is it possible to try sample measurements?
Yes. Please send your sample materials. We will send you the measurement results.
contact：info@aetjapan.com
- ■System Option
- 1 What are the reference materials?
Microwave Dielectormeter uses the two different reference materials with well known dielectric properties. By calibrating the measurement parameters with these materials, this system achives a quantitative accuracy. We use the two single crystals of SiO2 and MgO as the reference materials.
- 2. Which network analyzers can be used for the microwave dielectrometer?
Agilent technology PNA series, ENA series, 872x series, ANRITSU 37000 and Rohde & Schwarz network analyzers. If you have any other network analyzers, please contact us.