Application of high T/sub c/ superconductors as frequency selective surfaces: experiment and theory

The use of YBa/sub 2/Cu/sub 3/O/sub 7-x/ and Tl/sub 2/CaBa/sub 2/Cu/sub 2/O/sub 8/ high-temperature superconducting thin films to fabricate frequency selective surfaces (FSS) at millimeter-wave frequencies (75-110 GHz) is discussed. An analytical/numerical model was applied, using a Floquet expansion and the method of moments, to analyze bandstop superconducting frequency selective surfaces. Experimental results were compared with the model, and showed agreement with resonant frequency prediction with an accuracy of better than 1%. The use of the superconducting frequency selective surfaces as quasi-optical millimeter-wave bandpass filters was also demonstrated.<
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