Design of a superconducting UWB bandpass filter with tunable notch band

By studying the principles of ultra-wideband (UWB) and band-stop, a novel band-pass filter with adjustable band-stop characteristics is proposed. The filter achieves 3.1-10.6 GHz UWB bandpass characteristics through an improved multi-mode resonator. An L-shape λ/2 notch resonator loaded with a 2-bit reconfigurable interdigital capacitor (IDC) array is coupled to the multiple-mode resonator and generates a tunable notch band to reject any undesired signal that may interfere with the UWB passband. By connecting the IDC to the ground or not, the capacitance of each IDC and the corresponding notch frequency can be adjusted. After design and optimization, the final size of the superconducting filter is 20.0 mm × 6.9 mm, and the test results and simulation results are highly consistent.