Numerical estimation on intermodulation distortion of a high-temperature superconducting dual-band bandpass filter

This paper proposes a method that numerically estimates the intermodulation distortion (IMD) of a high-temperature superconducting (HTS) dual-band bandpass filter (DBPF) when two-tone signals are simultaneously input to each passband of the HTS-DBPF. The numerical estimation method is based on the third-order polynomial approximation of the input-output characteristics of the HTS-DBPF when a two-tone signal is input to each passband. To validate the proposed method, a 2.0-/3.5-GHz band HTS-DBPF is used to measure its IMD characteristics when two tones with a 30-kHz separation are individually and simultaneously input to each passband. The calculated and measured results confirm that the proposed method can be applied to estimate the IMD characteristics.