Precise Measurement for Temperature Dependence of Dielectric Rod Materials Using an Image-Type Resonator Method

Yoshinori KOGAMI  Yoshio KOBAYASHI  Masayuki KATOH  

IEICE TRANSACTIONS on Electronics   Vol.E77-C   No.6   pp.888-893
Publication Date: 1994/06/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Measurement Techniques for Microwave/Millimeter Wave)
dielectric rod resonator,  dielectric material,  temperature dependence,  measurement,  

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An image type resonator method is proposed as a method to evaluate precisely the temperature dependence of dielectric material. At first, the temperature coefficients of the resonant frequencies, TCf are measured separately using the shielded dielectric resonators of three types; that is a parallel plate type, and an image type, and a MIC type resonator. Secondly, an intrinsic temperature coefficient of the resonant frequency TCf0, which is defined as the temperature coefficient of a resonant frequency when all the stored energy is confined inside a dielectric, is estimated from these measured TCf. Actually, the TCf0 values of a sapphire and (Zr・Sn) TiO4 rod are estimated from the TCf values measured for the resonators of three types. As a result, for the parallel plate type, the precision of TCf0 is about 0.1 ppm/. For the image and MIC types, the errors of about 0.5 ppm/ in the TCf0 values arise from the errors in the linear expansion coefficients of the resonators, rather than from the experimental errors in TCf. Then, another image type resonator is designed to estimate TCf0 within error of 0.1 ppm/. In this design, dimensions of the shielding cavity is determined to reduce the influence of the errors in the linear expansion coefficients on precision of the TCf0 estimation. Finally, for a (Zr・Sn) TiO4 ceramic rod, a TCf0 value estimated from TCf measured for the image type resonator is obtained with accuracy of about0.1 ppm/.