A Novel Miniaturized Benchtop EPR Spectrometer Based on Sideband Detection Using a Software-Defined Radio

This paper presents a novel design and validation of a compact bench-top Electron Paramagnetic Resonance (EPR) spectrometer based on a software defined radio (SDR) platform. The miniaturization of traditional EPR systems is achieved by bespoke design of system components including an electromagnet, microwave resonant cavity with modulation coil and adjustable coupling, and an innovative microwave source and detection architecture using a software-defined radio. The proposed system demonstrates the capability to perform X-band EPR spectroscopy with a high signal-to-noise ratio. Preliminary test results using DPPH (2,2-Diphenyl-1-picrylhydrazyl) as a standard sample show successful detection and analysis of EPR spectra, confirming the system's efficacy.