# "Gap Effect" in Measurement of Large Permittivities (Correspondence)

About: This article is published in IEEE Transactions on Microwave Theory and Techniques.The article was published on 1966-08-01. It has received 32 citations till now. The article focuses on the topics: Reflection (physics).

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01 Jan 1990

197 citations

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TL;DR: In this article, an enhanced transmission reflection technique for the precise determination of the complex permittivity of dielectric materials partially filling the cross section of a rectangular waveguide is described.

Abstract: An enhanced transmission reflection technique for the precise determination of the complex permittivity of dielectric materials partially filling the cross section of a rectangular waveguide is described Dielectric properties are determined by an iterative procedure from two-port S-parameter measurements and a numerically generated propagation constant obtained from the analysis of a partially filled waveguide Convergence of the solution is ensured from perturbational approximations Unlike previous approaches, an uncertainty investigation is performed, taking into account all the parameters involved in the dielectric characterization Permittivity accuracy values are presented and, hence, an optimum measurement setup can be established Measurements of reference materials have been carried out to validate the method

87 citations

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01 Jan 2008

TL;DR: In this paper, a complex gyrator circuit of a Weakly Magnetized Junction Circulator (WMJC) is described, and the degree-2 Circulator Gap effects in Circulator Assemblies Suspended Planar Resonator Passband Frequencies of a Three-Port Junction in Immittance Plane Open Walls Spinwave Instability in Magnetic Insulators Frequency Doubling in Ferrites Second-Order Intermodulation in Magnetic insulators Temperature Stability of Magnetic Insulator Below the Kittel Line Third-Order intermodulation Products in Nonlinear Devices in Non Linear Devices

Abstract: This chapter contains sections titled: Complex Gyrator Circuit of Weakly Magnetized Junction Circulator Very Weakly Magnetized Gyromagnetic Resonator Weakly Magnetized Gyromagnetic Resonator Moderately Magnetized Gyromagnetic Resonator The Degree-2 Circulator Gap Effects in Circulator Assemblies Suspended Planar Resonator Passband Frequencies of a Three-Port Junction in Immittance Plane Open Walls Spinwave Instability in Magnetic Insulators Frequency Doubling in Ferrites Second-Order Intermodulation in Magnetic Insulators Temperature Stability of Magnetic Insulators Below the Kittel Line Third-Order Intermodulation Products in Nonlinear Devices

34 citations

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TL;DR: In this paper, the uncertainty of measurements of the complex permittivity epsilon /sub r/ and permeability mu /subr/ as a function of the normalized sample length l/ Lambda'due to the measured errors in the scattering coefficients S/sub 11/ and S/ sub 21/ is discussed.

Abstract: The uncertainty of measurements of the complex permittivity epsilon /sub r/ and permeability mu /sub r/ as a function of the normalized sample length l/ Lambda ' due to the measured errors in the scattering coefficients S/sub 11/ and S/sub 21/ is discussed. A simple analysis of epsilon /sub r/ and mu /sub r/ and some measured data are given, which allows one to determine the extent of l/ Lambda ' and maximum uncertainty of the combined total transmission-reflection method in application to radar absorber measurements. >

34 citations

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TL;DR: In this article, the relative dielectric constant er of high resistivity GaAs has been measured at 70.243 GHz as a function of temperature between 100 and 300°K.

Abstract: The relative dielectric constant er of high‐resistivity GaAs has been measured at 70.243 GHz as a function of temperature between 100 and 300°K. The measuring technique utilized a circular E field (TE°01) mode reflection‐coefficient bridge. Estimated relative and absolute accuracies of the measurements are ±0.2% and ±0.5%, respectively. The results are found to fit the equation er(T) = er(0){1 + αT} where er(0) = 12.73 ±.07 and α = (1.2 ± 0.1) × 10−4. At room temperature (295°K) the relative permittivity is er = 13.18 ±.07.

30 citations

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TL;DR: In this paper, the assumption that the material fills the waveguide uniformly was removed by treating the contact region with perturbation theory, and the results were found to be simply represented by a lumped-parameter equivalent circuit.

Abstract: Techniques employing rectangular waveguides to measure complex permittivity generally contain the tacit assumption that the material fills the waveguide uniformly. With semiconductors this assumption may be poorly satisfied near the waveguide walls due to (1) air gaps, (2) oxide layers, (3) potential barriers, and (4) distributed ``screening'' charges. The uniform‐filling assumption is removed in the present paper by treating the contact region with perturbation theory. The results are found to be simply represented by a lumped‐parameter equivalent circuit. Measurements performed on intrinsic germanium at 10.5 GHz agree well with the theory and indicate that unintentional air gaps and oxide layers dominate the measurements at high conductivities, even for ``tightly'' fitting samples.

49 citations

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TL;DR: In this article, the selection of a material suitable for use as a standard of dielectric properties at microwave frequencies is discussed, and tests are described which indicate that a glass and a glass ceramic are satisfactory for such standards.

Abstract: The selection of a material suitable for use as a standard of dielectric properties at microwave frequencies is discussed, and tests are described which indicate that a glass and a glass ceramic are satisfactory for such standards. The probable accuracy of measurement of the real part of the dielectric constant is estimated at ± 0.3 per cent. Loss measurements are discussed. A correction is developed for the error resulting from the small airgap often present around the sample in transmission-line measurements. The effects of humidity and temperature variations are examined, and preliminary results of measurements to 800°C are given.

30 citations