DNA sensing based on single element planar double split-ring resonator

In this paper, a feasibility of using double split ring resonator (DSRR) having negative permeability as a biosensor has been demonstrated. The compact DSRR has been excited by a microstrip transmission line, and the DNA hybridization in which single-stranded deoxyribonucleic acid (ss-DNA) is coupled with a complementary deoxyribonucleic acid (c-DNA), it is recognized with change in S₂₁ resonant frequency. When ss-DNA is immobilized onto gold (Au) surface and then is coupled with c-DNA, the resonant frequency has been changed by Deltaf_ss-DNA=20 MHz and Deltaf_{hybridization}=60 MHz for two cases. It is clear that DSRR can be utilized as a DNA sensing element at microwave regime.