Compact dual-mode filters for HTS satellite communication systems

Novel compact dual-mode narrow bandpass microstrip filters using degenerate modes in multizigzag arms of square loop resonators were analyzed as realized in superconducting 2- and 4-pole versions and found to have high performance, selectivity, and substantial size reduction, compared with current designs. A 2-pole copper filter, scaled nearly eight times larger to operate at a center frequency of 142 MHz and bandwidth of 1.4%, was fabricated, tested, and compared with the prediction of a CAD tool to validate predictions for other analyzed designs. The agreement was found to be good.