Resonant Characteristics of Two Closely Arranged Split- Ring Resonators

In this paper, we present the analysis of a metamaterial-based bandpass filter designed using two split-ring resonators (SRRs) co-located with each other. The resonance was optimized by adjusting the orientations of the concentric metallic rings. The resonating reflection coefficients of the double-SRR filters are compared with those obtained from the single-SRR filter. Owing to the constructive or destructive interference of the neighbouring fields, the performance of the double-SRR filter may either be enhanced or degraded. Optimum performance is achieved when the splits of the outer rings are orientated towards the bottom strip. At the resonance frequency, the impedance of the structure with optimum performance is found to be 63.64 ohm which is reasonably close to the 50 ohm characteristic impedance of the microstrip transmission lines.