Qishao Zhang

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In this paper, the complex permittivity of low loss microwave dielectric disk is measured in broad frequency band by applying cylindrical cavity. The measurement frequency band covers 7-18 GHz by using only one cavity which works in multimode. The paper mainly discusses the design of the cavity, measurement theory and mode search method after the sample is(More)
An improved image type sapphire resonator was developed for accurate measurement of surface resistance of a single piece of high temperature superconductor thin film. The surface resistances of two DC Spurting Yttrium-Barium-Copper Oxide (YBCO) thin films were measured by TE011 mode of this resonator. TE012 mode of this resonator was also used in the(More)
Complex permittivity is one of the most important parameters of microwave dielectrics. When the dielectrics work in high temperature environments, the complex permittivity as a function of temperature should be measured while designing dielectrics and applying in microwave devices or radome. A test cavity used at temperature up to 1500degC is designed and(More)
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