用外差混频和直接检波方法测量亚毫米波连续波源的频谱

摘要

It is of particular interest to characterize the frequency spectrum of signal sources at submillimeter wavelengths.The heterodyne-mixing and direct-detection (Fourier transform spectrometer, FTS) methods were introduced to measure the frequency spectrum of a submillimeter CW source (phase-locked and tunable from 460-520 GHz). A 500-GHz superconductor-insulator-superconductor (SIS) tunnel junction was employed as a mixer for the former method but a direct detector for the latter. The measurement results are compared.%在亚毫米波频段,表征信号源的频谱特性是一项重要工作.用外差混频和直接检波(傅里叶变换频谱仪,FTS)两种方法测量一个亚毫米波连续波源(采用锁相技术且可在460～520GHz范围内调频)的频谱.500～GHz频段超导SIS隧道结在外差混频方法里用作混频器,而在直接检波方法里作为直接检波器.并对两种方法得到的结果进行了比较.