Quasistatic Resonators Based Triple-Mode Notched Microstrip Bandpass Filter

Abstract

This article discusses new approach for design and development of triple-mode notched microstrip bandpass filter based on quasistatic resonators(QR). The proposed approach is composed of two Quasistatic resonant elements; Horizontal plane Split ring resonator (HP-SRR), Vertical plane split ring resonator (VP-SRR) and a single asymmetric step impedance resonator (A-SIR) with parallel coupled feed structure. An additional attenuation pole realized by VP-SRR in desired passband, tunes the dual-mode response to triple mode and enhances the 3dB bandwidth without changing the dimensions of basic the filter cell. The HP-SRR realizes a notch at WiMAX band (IEEE 802.11a lower band) in the desired passband. Further by changing the impedance of VP-SRR and HP-SRR both the location of additional attenuation pole frequency and notch band can be controlled. The proposed approach results in compact, notched wideband, filter design.