Microwave Properties of Liquid Phase Epitaxialy Grown YBa2Cu3Ox Films

YBa2Cu3Ox films were grown on MgO (100) substrates by liquid phase epitaxy. Their microwave properties were examined. A microstrip resonator at 10.8 GHz with a YBCO ground plane shows unloaded Q values of 14200 at 77 K and 23300 at 40 K, which correspond to surface resistance values of 650 μΩ and 400 μΩ, respectively. A microstrip four-pole band-pass filter, with a midband frequency of 10 GHz and a fractional bandwidth of 2% shows an insertion loss less than 0.2 dB and a return loss better than 15 dB at 77 K. The nonlinear behavior of this filter was studied by intermodulation distortion measurements. This filter shows relatively high power handling capabilities with a third-order intercept point of + 65 dBm at 77 K.