Superconductor/nonlinear-dielectric bilayers for tunable and adaptive microwave devices

We have designed, fabricated and characterized electrically tunable and adaptive microwave devices using coplanar waveguide (CPW) structures which incorporate bilayers of superconducting YBa2Cu3O7-x and nonlinear dielectric SrTiO3 on 1 cm x 1 cm x 0.5 mm LaAlO3 substrates. The microwave devices include voltage-tunable phase shifters and delay lines, voltage-tunable mixers, and voltage-tunable and adaptive bandpass filters. Under de voltage bias, these compact CPW devices exhibit more than 360 degrees relative phase shift at 2 GHz, more than 30 dB tunability in mixed microwave power between 0.7 GHz and 5.9 GHz, and fine-tunable symmetric filter profile at around 2.5 GHz with less than 2% bandwidth and more than 15% adaptive range.