Basic detection of x band electron spin resonance signal using stripline resonator

Abstract

In this work, the basic detection of electron spin resonance (ESR) signal by using stripline resonator was demonstrated. The signal was detected by using a basic homemade ESR setup, stripline resonator and a sample known as 2,2-diphenyl-1- picrylhydrazyl (DPPH). Two types of stripline resonators were designed, simulated and fabricated to detect ESR signals by varying externally applied static magnetic field strength or the microwave frequency. These respective designs were called as straight and U-shape design. The techniques used to fabricate the stripline resonators were ultraviolet (UV) lithography and milling by computer numerical controlled (CNC) machine. These resonators were named as UV,Mand U resonator, UV andMresonator have straight design while U resonator is a U-shape design. UV resonator has unloaded resonance frequency at 9.12 GHz and Q-factor is 88. M resonator has unloaded resonance frequency at 9.70 GHz and Q-factor is 70. U resonator has unloaded resonance frequency at 9.70GHz and Q-factor is 121. Using these resonators, the ESR signal was successfully detected from the DPPH. By fitting using Lorentzian equation to the ESR signal, the experimental g-factor was determined. U-shape resonator had the highest accuracy with g-factor of 2.017 or 0.66% difference with the theoretical value. Simulation and experimental results conclude that resonator with the higher microwave magnetic field gives a stronger signal.