A NOVEL HTS FILTER WITH IMPROVED OUT-OF-BAND REJECTION BY INTRODUCING A QUARTER-WAVELENGTH SPIRAL STUB

摘要

A novel high temperature superconducting (HTS) filter with split-end stepped impedance resonators (SIR) is developed on MgO substrate. Spiral feedlines are used to meet the requirement of the external quality factor. A quarter-wavelength (λ/4) spiral stub is introduced at the input feedline to provide additional transmission zeros at the high frequency end, which can improve both the out-of-band rejection and band-edge steepness. The measured results at 70 K are in good agreement with the simulated ones.