Asia-Pacific Microwave Conference (APMC)
Characterization of a Quasi-Optical NbN Superconducting HEB Mixer at 300 GHz
W. Miao, Ling Jiang, Yi Luo, Z.H. Lin, Qi Yao, S. C. Shi
Abstract
In this paper, we present the performance of a quasi-optical NbN superconducting HEB (hot-electron bolometer) mixer cryogenically cooled by a 4-K close-cycled refrigerator. The variation of resistance of the NbN HEB mixer with respect to temperature is examined at first. Its receiver noise temperature and conversion gain are measured at different dc bias voltages and LO pumping levels. The lowest receiver noise temperature is 1400 K (with no corrections), and reduced to about 358 K after eliminating the quasi-optical losses. The stability of IF output power of this HEB mixer is also discussed.