A 27-mW Ka-Band Complex Dielectric Sensor Chip With Readout and Reference Circuits Using 1.2-V Supply in 130-nm SiGe BiCMOS

The capability to sense the dielectric properties of liquids and tissues is valuable in many applications, because accurate assessment of the material composition can be made from the complex permittivity measurements. Laboratory-on-chip systems for continuous dielectric monitoring impose low-voltage and low-power operation on the circuits to enable long-term use without battery replacement. In addition, high level of integration is necessary to facilitate the implementation of 2-D sensor arrays. This letter presents the design and characterization of a SiGe BiCMOS capacitive sensing oscillator-based complex dielectric sensor chip at Ka -band operating with a supply voltage of $\mathrm {1.2 \, \text {V}}$ and consuming $\mathrm {27 \, \text {m} \text {W} }$ . The chip is integrated with readout circuits to provide simple dc outputs for easier processing and with reference circuits to serve as a tool to compensate for both the external and internal variations, which affect the sensor output. The experimental results show that different alcohols can be differentiated using the proposed sensor chip.