Critical design issues in implementing a YBCO superconductor X-band narrow bandpass filter operating at 77 K

The implementation of a narrowband (0.5%) high-T/sub c/ superconducting filter operating at X-band and 77 K is discussed. The authors examine the effects of high-temperature superconductor (HTS) film thickness on the loss performance; kinetic and mutual inductance contributions to the center frequency drift with temperature; and nonlinearities associated with the generation of intermodulation distortion. It is concluded that, in order to design high-performance circuits with HTS materials, kinetic inductance effects and the generation of intermodulation products must be controlled. Film thickness and uniformity are key parameters to low-loss performance.<>