A Rotational Planar Circular Split Ring Resonator Sensor for Angle Rotation Detection Applications

This paper introduces a planar circular split ring resonator (CSRR) coupled to microstrip transmission line (TL) for rotation angle sensing applications. For each rotation angle, the CSRR acts as a stop-band filter that absorbs the signal flow through the TL. The CSRR sensor introduces a resonance frequency at 4.13 GHz with a − 10 dB bandwidth of 370 MHz. High attenuation coefficient of 40 dB is achieved with reflection magnitude of 0.17 dB. A parametric study on the effect of each CSRR design parameters on the performance of the sensor is introduced. Mathematical modelling of the variations of resonant frequency with different design parameters are derived and verified. The performance of the proposed sensor for rotation angle detection is investigated. A five-elements equivalent circuit model is prepared to represent the inductive and capacitive coupling of the CSRR and TL. The sensing behaviour of the CSRR sensor placed on object with different materials is introduced. The particle swarm optimization (PSO) is employed to find the optimal values of the equivalent circuit elements at different rotation angles.