High-sensitivity HTS receiver module with hermetic thermal insulation waveguides

We have proposed a high-sensitivity high-Tc superconducting (HTS) receiver module with hermetic thermal insulation waveguides. The hermetic thermal insulation waveguide consists of two silver-plated aluminum oxide waveguides and copper wall. The waveguide with a gap between the aluminum oxide waveguides realizes thermal insulation between room temperature and low temperature. And the hermetic waveguide is connected to a vacuum flange to seal the vacuum chamber. This waveguide operates in the 3 GHz band and the dimension of this wavegide is 6.9 × 26.1 mm, one-third of the size of a conventional hollow metallic waveguide. The waveguide realizes an insertion loss of 0.4 dB and thermal conductivity 1/10 that of 2.2φ semi-rigid coaxial copper cable. The HTS receiver module is composed of the developed waveguides, an HTS filter, a cryogenic low-noise amplifier (LNA), and a limiter. The HTS receiver module realized low thermal noise of 60 K.