17 research outputs found
Precise microwave characterization of MgO substrates for HTS circuits with superconducting post dielectric resonator
Accurate data of complex permittivity of dielectric substrates are needed for
efficient design of HTS microwave planar circuits. We have tested MgO
substrates from three different manufacturing batches using a dielectric
resonator with superconducting parts recently developed for precise microwave
characterization of laminar dielectrics at cryogenic temperatures. The
measurement fixture has been fabricated using a SrLaAlO3 post dielectric
resonator with DyBa2Cu3O7 end plates and silver-plated copper sidewalls to
achieve the resolution of loss tangent measurements of 2 {\times} 10-6. The
tested MgO substrates exhibited the average relative permittivity of 9.63 and
tan {\delta} from 3.7 {\times} 10-7 to 2 {\times} 10-5 at frequency of 10.5 GHz
in the temperature range from 14 to 80 K.Comment: 6 pages, 8 figures, 3 table
Comparing unloaded Q-factor of a high-Q dielectric resonator measured using the transmission mode and reflection mode methods involving S-parameters circle fitting
A comparative study of unloaded Q-factor measurements of a TE011 mode sapphire dielectric resonator with unloaded Q-factor value of 731,000 at a frequency of 10 GHz and temperature of 65 K using two best Q-factor measurement methods are presented. The transmission (TMQF) and reflection methods are based on relevant multifrequency S-parameter measurements and circle-fitting procedures to compute the unloaded Q-factor of the resonator. For accurate comparison of the methods, a delay compensation procedure (introduced in the TMQF technique to remove delay due to noncalibrated cables) has been applied also to the reflection data