Mode-splitting Phenomena and Enhanced Notch Depth in Microstrip Transmission Line Loaded with Two Similar Square-shaped Split Ring Resonators

An ideal notch filter in microwave regime is proposed using a microstrip line (MTL) which can be loaded with two optimally coupled non-adjacent similar squareshaped split ring resonators (S-SRRs). The S-SRRs, each having a single split-gap in the vertical arm, are placed on opposite sides of the microstrip line. Also, centre-to-centre distance between the S-SRRs along the strip line is assumed to be equal to the side-length of a ring. An enhanced notch depth (transmittance of about -65dB) is observed at optimal coupling positions of SRRs with MTL when the split rings are placed asymmetrically with respect to the INPUT/OUTPUT ports. Also, a mode-splitting phenomenon with resonance shifting in MTL is observed with relatively adjacent positions of this type of two split ring resonators.