21.4 A microfluidic-CMOS platform with 3D capacitive sensor and fully integrated transceiver IC for palmtop dielectric spectroscopy

Quantitative measurement of the complex relative dielectric permittivity (ε
_r
) of a material vs. frequency (i.e., dielectric spectroscopy, or DS) is a powerful monitoring technique that extracts key information on molecular characteristics of the material-under-test (MUT) via its interactions with electromagnetic waves in a broad frequency range. Despite its potential as a label-free, nondestructive, real-time and fully electrical monitoring modality for myriad applications, including structural biology, fermentation monitoring for alcoholic beverages, food safety control and clinical diagnostics, DS is still underutilized as an analytic tool in scientific research or clinical settings. This is due to the dearth of an autonomous, small-sized, low-power and portable instrument to conduct MHz-to-GHz DS measurements without requiring a microwave probe station, benchtop vector network analyzer (VNA) equipment, or large (100's of ml) sample volume.