Development of laser-controlled high temperature superconducting microwave variable attenuator with low loss and attenuation step

This paper proposes new a laser-controlled superconducting microwave variable attenuator which can be used in high- temperature superconducting (HTS) subsystem of satellites. The design process and experimental results are analyzed. Low microwave surface resistance and excellent laser response characteristics of HTS film are contributed to the favorable properties of this attenuator. A transition metal and a transparent material are adopted in the structure of HTS attenuator to ensure the grounded capability and the laser position on substrate. The results show that this attenuator, which is 12 mm×8 mm×0.5 mm and works at low temperature, can be used alone or integrated into HTS system to decrease system volume and weight. Insertion loss of this attenuator is about 0.2 dB, whose magnitud