A 5-to-8-GHz Wideband Miniaturized Dielectric Spectroscopy Chip With $I/Q$ Mismatch Calibration in 65-nm CMOS

This paper presents a fully integrated broadband biosensor chip for miniaturized dielectric spectroscopy (DS). The proposed biosensor chip consists of wideband exciting signal source and high sensitivity receiver. The exciting signal source consists of a wideband phase-locked loop (PLL) and output drivers. The wideband receiver is composed of low noise amplifier, mixer, and output buffers. The proposed receiver with in-phase (<inline-formula> <tex-math notation="LaTeX">${I}$ </tex-math></inline-formula>) and quadrature-phase (<inline-formula> <tex-math notation="LaTeX">${Q}$ </tex-math></inline-formula>) signals mismatch calibration measures the frequency-dependent S21 magnitude and phase of a microfluidic dielectric sensor. The DS system implements a modified frequency response analysis by converting the biosensor response signal from the RF excitation frequency to low frequency using a passive mixer. Dielectric measurements results of ethanol with the proposed biosensor chip in the range of 5–8 GHz are in excellent agreement (error <1%) with theoretical values. The chip is fabricated in 65-nm CMOS process. The total power consumption is 18 mW with 1.2-V supply.