A Rudimentary X band CW-EPR Spectrometer Based on FPGA


  • Wei Siang Eow Universiti Teknologi Malaysia
  • Yung Szen Yap Universiti Teknologi Malaysia




Electron Paramagnetic Resonance, Resonator, EPR Spectrometer


A rudimentary Electron Paramagnetic Resonance (EPR) spectrometer is design using a field programmable gate array (FPGA) equipped with two digital-to-analog (DAC) and two analog-to-digital (ADC) channels.  The single stage heterodyne setup operates at X band frequencies and is used to detect EPR signals from 2,2-diphenyl-1-picrylhydrazyl (DPPH) in a loop-gap resonator.  We design the loop gap resonator with 3 loops 2 gaps for high field homogeneity and moderate Q-factor. The resonator is coupled capacitively to the coaxial cable and is designed to have an unloaded resonant frequency of 8.856 GHz with a Q-factor of 646.0 when critically coupled. The loaded resonant frequency is reported to be 8.668 GHz with a Q-factor of 615.8. Using this setup, EPR signal is successfully detected at 311.4 mT and 8.688 GHz with an experimental g-factor of 1.99450.0012, which is very near to the standard value for DPPH.


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