A CMOS 160GHz Integrated Permittivity Sensor with Resolution of 0.05% Δεr

This paper presents a high-resolution permittivity sensor at 160GHz in 28nm CMOS. It incorporates a THz high Q silicon whispering gallery mode resonator sensor that boosts the system's permittivity sensitivity. Multifold noise reduction techniques are adopted. A novel complementary BPSK signaling suppresses the common mode noise and the low frequency noise from within the system and the environment. Transmitter (TX) local oscillator (LO) feedforward that injection-locks the receiver (RX) mitigates the TX phase noise. The sensing system achieves the best permittivity sensing resolution of 0.05%
$\Delta\varepsilon_{r}$
among the state-of-the-art permittivity sensors within 14us of integration time and 54mW power consumption.