A Miniaturized 3-10GHz Dual-Comb Spectroscopy System for Chemical Detection

This paper presents a miniaturized dual-comb spectroscopy (DCS) system in ultra-wideband (UWB) frequency range. In this system, two comb generators produce UWB frequency combs with slightly different repetition frequencies. One of the frequency combs is passed through a microstrip sensor loaded by a material under test (MUT) and then is combined with the other comb. After that, the combination experiences second order nonlinearity by a diode detector. Consequently, the effect of MUT in the UWB is downconverted to the baseband. Successful detection of MUTs including air, ethanol, and methanol according to the output magnitude is demonstrated in this paper.