Critical Limitations in Low-Loss Narrow-Band HTSC Filter Design

Simulation and experimental results for 18 GHz central frequency and 1-2 % bandwidth YBCO/MgO microstrip bandpass filters are presented. The simulation has been carried out using recently developed HTSC microwave software, Vendik and Kollberg (1), comparing the results with commercially available software (Microwave and RF Design Systems (mds) from Hewlett Packard, and Microwave Harmnonica (MH) from Compact Software). Problems limiting narrow-band microstrip filter development at millimeter wavelengths are studied and discussed.