Techniques for the Measurement of Complex Microwave Conductivity and the
01 Jan 1970-
About: The article was published on 1970-01-01 and is currently open access. It has received 17 citations till now.
Citations
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TL;DR: An overview of transmission/reflection-based methods for the electromagnetic characterisation of materials is presented in this article, which is applicable to conventional transmission reflection devices such as coaxial cables or waveguides.
Abstract: An overview of transmission/reflection-based methods for the electromagnetic characterisation of materials is presented. The paper initially describes the most popular approaches for the characterisation of bulk materials in terms of dielectric permittivity and magnetic permeability. Subsequently, the limitations and the methods aimed at removing the ambiguities deriving from the application of the classical Nicolson–Ross–Weir direct inversion are discussed. The second part of the paper is focused on the characterisation of partially conductive thin sheets in terms of surface impedance via waveguide setups. All the presented measurement techniques are applicable to conventional transmission reflection devices such as coaxial cables or waveguides.
92 citations
TL;DR: In this article, the use of the network analyzer to measure the dielectric properties of materials over a broad frequency range is described, with simple procedures for obtaining initial estimates and unambiguous solutions for the parameters.
Abstract: This paper outlines the use of the network analyzer to measure the dielectric properties of materials over a broad frequency range. The method described here is based on transmission techniques with simple procedures for obtaining initial estimates and unambiguous solutions for the dielectric parameters. A further feature is that this measurement technique provides a degree of self-checking for inconsistent results.
43 citations
TL;DR: A simple yet powerful method is proposed for removing the multiple solutions problem in the complex permittivity, ϵ, determination from measured transmission scattering parameter measurements of lossy materials by derived a one-variable objective function for fast evaluation.
Abstract: A simple yet powerful method is proposed for removing the multiple solutions problem in the complex permittivity, ϵ, determination from measured transmission scattering (S-) parameter measurements of lossy materials. The method uses amplitude-only measurements at two slightly separated frequencies to estimate an accurate initial guess. For this purpose, we derive a one-variable objective function for fast evaluation, which lends itself to measurement automation. The method provides an estimation for real and imaginary parts of the ϵ, which can be utilized as a measure for checking the correctness of initial ϵ estimate. The method is very useful for band-limited measurements. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 337–341, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24048
39 citations
TL;DR: In this paper, the cavity coupling factor in the absence of perturbation, together with the change in the reflected power and the cavity resonance frequency shift, are used for the determination of the material properties.
Abstract: Cavity perturbation techniques offer a very sensitive highly versatile means for studying the complex microwave conductivity of a bulk material. A knowledge of the cavity coupling factor in the absence of perturbation, together with the change in the reflected power and the cavity resonance frequency shift, are adequate for the determination of the material properties. This eliminates the need to determine the Q-factor change with perturbation which may lead to appreciable error, especially in the presence of mismatch loss. The measurement accuracy can also be improved by a proper choice of the cavity coupling factor prior to the perturbation.
22 citations
TL;DR: In this article, the uncertainties of conductivity σ and dielectric constant e of the short-circuited line (SCL) method due to the measured errors in the VSWR and the position of standing-wave minimum are studied.
Abstract: The uncertainties of conductivity σ and dielectric constant e of the short-circuited line (SCL) method due to the measured errors in the VSWR and the position of standing-wave minimum are studied. In order to cover most of the fast ion conductors, the range of σ from 10-4 to 1.0/(Ω-cm) is considered. The results of the analysis provide the order of accuracy one can achieve in these measurements. The effects of sample thickness, high conductivity, and negative dielectric constant upon uncertainty are examined. Measurements on a chlorobenzene sample are used to simulate this analysis. A relationship between σ, e, and operating frequency is derived which makes it possible to determine the limits of applicability of the SCL method.
18 citations
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62 citations
01 Jun 1964
TL;DR: In this article, an accurate reflection bridge technique for measuring microwave conductivity and permittivity is described, and measurements of n-type silicon and p-type germanium at 24 Gc and at temperatures between 77° and 300° Kelvin are presented and compared with theory.
Abstract: The conduction process in semiconductors exhibits effects associated with inertia of the carriers when the observation frequency is comparable to the reciprocal of the relaxation time for randomization of momenta. These effects can cause significant changes in the conductivity and permittivity of germanium and silicon measured at ordinary microwave frequencies and should become increasingly important as semiconductor devices are developed for ultra-microwave applications. The present paper derives equivalent circuits which illustrate inertial effects and discusses their temperature dependence. A highly accurate reflection bridge technique for measuring microwave conductivity and permittivity is then described. Finally, measurements of conductivity and permittivity of n-type silicon and p-type germanium at 24 Gc and at temperatures between 77° and 300° Kelvin are presented and compared with theory. At 77°, the inertial effects are found to be largest for the p-type germanium and cause the microwave conductivity to be less than the dc conductivity by a factor of one-half.
59 citations
TL;DR: In this article, the complex microwave conductivity of lightly-doped n and p-type silicon and genmanium was measured by observing the reflectivity of the circular T E01 mode at 48 GHz and were thus free of errors caused by the impedance of the waveguide.
Abstract: This paper presents measurements of the complex microwave conductivity of lightly‐doped n‐ and p‐type silicon and genmanium as functions of impurity concentration and of temperature between 77° and 300°K. The measurements were obtained by observing the reflectivity of the circular T E01 mode at 48 GHz and are thus free of errors caused by the impedance of the waveguide‐sample contact. Analysis utilized currently accepted scattering models including ionized impurity scattering, intravalley acoustic and optical mode scattering, and intervalley scattering. The results are used to investigate the temperature and doping dependence of the average relaxation time and the conductivity ``effective'' mass.
47 citations
TL;DR: In this paper, the authors used the TE01° mode of circular waveguide in a ''reflection coefficient bridge'' to eliminate the source of error caused by the impedance of the contact between the sample and the broad waveguide wall.
Abstract: Microwave conductivity of semiconductors determined from transmission or reflection of the dominant mode of rectangular waveguide may contain a significant error caused by the impedance of the contact between the sample and the broad waveguide wall. This error increases with increasing bulk conductivity. The present paper describes a technique which eliminates this source of error by utilizing the TE01° mode of circular waveguide in a ``reflection coefficient bridge.'' Measurements of intrinsic germanium at 48 GHz show no contact influence over the conductivity range between 2 and 2×103 mho/m. In contrast, the conductivity measured with a conventional rectangular waveguide transmission bridge saturates at about 50 mho/m.
34 citations