One-Bit Measurements in Microwave Resonators

Microwave resonators are used to measure the dielectric constant of a material when feeding the microwave cavity with radio-frequency (RF) signals. Usually, the readout system is based on complex frequency-domain instrumentation or RF receivers. Results by Carbone et al. (2023) show how to sense RF signals in the time-domain by means of a low-complexity system to estimate the impedance of a microwave resonator. The method is based on the conversion of the resonator output signal using a high-speed analog comparator. It uses the comparator binary output to estimate the full-resolution signal carrying information about the resonator frequency response function. This article extends those results by illustrating a new measurement method that includes the possibility to account for hysteresis in the used analog comparator. Results are also extended to include not only signal sensing but also to produce actual measurement results based on fitting one-bit data processed by the presented algorithm to the Lorentzian function modeling the cavity frequency response function. Experiments are used to validate assumptions under various experimental settings.