Design of high performance hts filter at 183 MHz

A compact eight-pole high temperature superconducting(HTS)filter with a 2 MHz bandwidth at 183 MHz is developed on a 2-inch MgO substrate.The measured response of the filter shows a high performance without any tuning.We use a compact half-wavelength spiral resonator in the design process.The linewidth of the resonator is 80μm,and the gap between tracks is 80μm.The fabrication process was carefully carried out,and the untuned measured results of the filter show a high performance.The passband insertion loss is less than 0.27 dB,and the return loss is better than 13.8 dB.The measurement of the untuned HTS filter connected with a low noise amplifier(LNA)shows an excellent performance with return loss better than 15.8 dB and power gain 20.7±0.08 dB.