Broadband electron paramagnetic resonance spectrometer from 1 to 15 GHz using metallic coplanar waveguide

We report a broadband electron paramagnetic resonance (EPR) spectrometer that operates continuously in the frequency range from 1 to 15 GHz. A broadband metallic coplanar waveguide is utilized as the probe. The system is capable of performing EPR measurements in both continuous wave and pulsed modes. Its performance has been tested with a sample, named 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl powder, at room temperature. In the continuous wave mode, the sensitivity of the spectrometer is estimated to be 3.3×10¹² spins/gaussHz at 13 GHz. In the pulsed mode, inversion recovery experiments were carried out to obtain the spin-lattice relaxation time of the sample.