Plenary talk — Developments of HTS microwave passive and active devices and their applications in space and on ground

Summary form only given. Due to their very small surface resistance, high temperature superconductors (HTS) can be used to construct high performance microwave passive devices, e.g., filters with negligible insertion loss, very large out-of-band rejection, and extremely steep skirt slope. Moreover, by integrating the HTS filter and semiconductor pre-amplifier together with a cryo-cooler, the noise figure of the system can be further reduced. In the past ten years, various kinds of HTS filters have been designed and successfully applied in many fields. Aiming to satellite applications, an experimental HTS microwave receiver front end had been constructed and passed all the space qualification tests. The first Chinese space HTS subsystem was taken into space with a civilian experimental satellite for new technology (Shi Jian - 9) on October 14, 2012. Data received from this satellite show that the HTS filter is working on orbit perfectly. A space science research system with ultra-wide band HTS filter is also under development as a payload of Chinese first space laboratory (Tian Gong -2). Applications of HTS filters on the ground are also attractive. A demonstration HTS meteorological radar station was set up in Beijing and it showed great improvements in sensitivity and anti-interference ability in urban area wind profile measurements. HTS system was constructed for applications with high power handling requirements, e.g., TD-SCDMA system mobile base station. The HTS system showed very good results in reducing bit error rate for weak signals, strong enhancement in anti-interference and excellent compatibility in restricting spurious power of emitting signals. Improvements in video communications are also remarkable. More sophisticated Josephson junction based microwave active devices are less developed due to the rather challenging HTS Josephson junction technology. We have, however, recently made major progress in developing novel HTS monolithic microwave integrated circuit (MMIC) RF receiver front-end. The described monolithic HTS circuit consists of a HTS step-edge Josephson junction mixer, a 10-12 GHz HTS bandpass filter for RF input, a lowpass filter for IF output, and a resonator for local oscillator. All the HTS components are fabricated on a single 10 mm × 20 mm chip of YBCO film on MgO substrate. The monolithic frequency down-converter demonstrated superior performance in terms of conversion efficiency, dynamic range, linearity, and low power consumption. It operates stably from 20 K to 80 K with the best conversion loss less than 1 dB at 20 K.