Broadband Spectroscopy of Materials with an Integrated Comb-Based Millimeter-Wave Detector

A miniaturized broadband spectroscopic sensor using a fully integrated millimeter-wave detector is presented. The detector chip generates a frequency comb with a tunable spacing as a reference to downconvert received signals. By tuning the comb spacing, the detector can detect frequency tones from 50 GHz to 155 GHz with a resolution only limited to the linewidth of comb tones. A spectroscopy setup including the detector and four sheets made of different materials is implemented to characterize the frequency response of materials in this frequency range.

Broadband spectroscopy of four objects made of different materials is demonstrated from 50 GHz to 155 GHz with a fully integrated comb-based mm-wave detector. It is shown that each object exhibits a unique response which can help us in identifying unknown objects using mm-wave frequency combs.