Development of a 22 GHz receiver for Yamaguchi 32-m radio telescope

我们研制了22 GHz的制冷低噪声接收机，这是东亚VLBI网络的一个重要观测频率。22 GHz接收机由一个冷却偏振器、两个同时接收双极化的低噪声放大器、混频器和两个放大器以及后端组成。采用独特的小孔噪声注入校准系统。这个孔也用来烘干波导。低噪声放大器的噪声温度约为25K，由于偏振器也是用低噪声放大器冷却的，因此接收噪声温度低于45K。

We have developed a cooled low-noise receiver at 22 GHz, which is an important observational frequency of the East-Asian VLBI Network. The 22 GHz receiver is composed of a cooled-polarizer, two Low Noise Amplifiers (LNA) for receiving dual polarization simultaneously, mixers and two amplifiers, and back-end. A unique calibration system using a small hole for noise injection is adopted. This hole is also used for drying the waveguide. The noise temperature of the LNA is about 25 K. Since the polarizer is also cooled with the LNAs, the receiver noise temperature of below 45 K was achieved.