Computer modeling of microwave stripline resonators for non-invasive sensing

Microwave stripline resonators of rectangular and double rectangular shapes for non-invasive sensing have been designed and investigated experimentally and numerically. The resonator of single rectangular shape has had a resonance at about $4.32\ GHz$ for S$_{21}$ and the resonator of double rectangular shape has had resonances at about $3.5\ GH$z for S$_{21}$ and $5.85\ GHz$ for S$_{11}$. The simulation results for the sensitivity of the single rectangular and double rectangular resonators were $-0.023\ dB/(mg/dL)$ (glucose concentration) and $0.0143\ dB/(mg/dL)$ (NaCl concentration), respectively. The electromagnetic field distribution of the resonators was visualized and compared using computer simulation software HFSS. The obtained data have shown the accuracy of resonators as a non-invasive sensor for biophysical applications.