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.

中文翻译：

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基于级联约瑟夫森结的 8-10GHz 低损耗镜像抑制 HTS 混频器

7.8–9.8-GHz 低损耗高 $T_{c}$ 这封信中介绍了超导 (HTS) 镜像抑制约瑟夫森结混频器。镜像抑制是使用低损耗镜像抑制滤波器和一对并联双模谐振器实现的。三个级联约瑟夫森结与阻抗匹配网络和带通/低通滤波器单片集成在单个芯片上，以实现低损耗和紧凑性。串联结阵列的实施增加了整体结等效阻抗，从而实现了更好的阻抗匹配。新型 HTS 混频器的测量结果显示，在所需频率内，转换损耗低至 5.5 dB，镜像抑制比超过 30 dB。所提出的级联结配置为 HTS 混频器设计中的阻抗匹配提供了一种新方法，并且所展示的混频器性能使其成为 $X$ -波段雷达系统。