A 7.8–9.8-GHz low-loss high- $T_{c}$ superconducting (HTS) image-reject Josephson junction mixer is presented in this letter. Image rejection is achieved using low-loss image rejection filters and a pair of parallel… Click to show full abstract
A 7.8–9.8-GHz low-loss high-$T_{c}$ superconducting (HTS) image-reject Josephson junction mixer is presented in this letter. Image rejection is achieved using low-loss image rejection filters and a pair of parallel dual-mode resonators. Three cascaded Josephson junctions are monolithically integrated with impedance matching networks and bandpass/low-pass filters on a single chip for low loss and compactness. The implementation of series junction array increased the overall junction equivalent impedance, so that a better impedance matching is achieved. Measurement results of the novel HTS mixer showed a low conversion loss at 5.5 dB and an image-reject ratio over 30 dB within the desired frequency. The proposed cascaded junction configuration provides a new approach for impedance matching in HTS mixer designs, and the demonstrated mixer performance makes it an ideal candidate for $X$ -band radar systems.
