A 1.4 THz Quasi-optical NbN Superconducting HEB Mixer Developed for the DATE5 Telescope
2015-05-07Fig1. Measured near-field amplitude (left) and phase (right) distributions at 850 GHz. Note that the signal source is 500 mm away from the HEB mixer
In order to characterize the performance of this superconducting HEB mixer, a series of experiments have been performed in Millimeter and Sub-Millimeter Lab of Purple Mountain Observatory. The double-sideband receiver noise temperature was measured by Kangmin ZHOU and Wei MIAO, and is 600 K at 1.3 THz which can be as low as 300 K with the optical losses corrected. The intrinsic frequency response of the HEB mixer was measured by Kangmin ZHOU and Shaoliang LI, it shows a high coupling efficiency in the frequency range of 0.8~1.5 THz, in good agreement with the simulated coupling efficiency of the twin-slot antenna. The far-field beam pattern of the HEB mixer, measured by Kangmin ZHOU, Zheng LOU and Jie HU, agrees well with the simulated one. The coupling efficiency between the measured beam pattern and a fundamental-mode Gaussian beam is 0.98 and 0.995 in E-plane and H-plane, respectively.
All the results of our measurements have been published by IEEE Transactions on Applied Superconductivity, for a little more insight into this research see: