Microwave Chemical Sensing at Room Temperature Using an Overmoded Waveguide Design

Microwave spectrometers have unique advantages in the ability to determine high-resolution features that are specific to a given chemical. Very sharp lines which correspond to quantum states of the chemical allow for unique identification of the chemical. Recent advances have shown the possibility of room-temperature microwave spectroscopy analysis in which the data are collected in a short amount of time using broadband chirp pulse Fourier transform microwave (CP-FTMW) spectroscopy. In this paper, we explore the design of reduced-size spectrometers focusing on the reduction of the microwave analysis cell, where the chemical is analyzed at room temperature. Through optimization of the features of the test cell, it is shown that a much smaller analysis cell can be utilized. In combination with the established trends towards system on chip high-frequency devices, this technique demonstrates the possibility of a nonlaboratory-based implementation of a high-resolution sensor.