Abstract: Based on the process of signal transmission and detection of the continuous wave electron paramagnetic resonance (CW-EPR) system, a simulation model of signal transmission, modulation, and detection of the CW-EPR system is constructed by the Simulink platform. The model covers the signal source simulation, modulation, detection by the Schottky diode detector, and demodulation process based on a lock-in amplifier. Based on the model, the spectral signal variation process of DMPO samples under modulation amplitude and modulation phase variations is evaluated. The simulation results show that for different modulation amplitudes and modulation phases, the simulation results of the wave spectrum signals are consistent with the actual measurements. Therefore, the simulation model of CW-EPR signal transmission and detection established in this paper provides theoretical support for the in-depth understanding of the CW-EPR phenomenon, the optimization of experimental parameters, and the guidance of CW-EPR experiments, and it can be used as a reference for the design and optimization of the EPR system in the subsequent research.

Key words: continuous wave electron paramagnetic resonance, system simulation, spectrum signal processing and detection, Simulink