UWB dual notch implementation using folded bi-section stepped impedance resonator

Abstract

This paper proposes a method for dual notch implementation in ultra wideband (UWB) using a simple stepped impedance resonator (SIR). The impedance ratio and electrical length ratio of a bi-section stepped impedance resonator (BSIR) are optimized to have the transmission zeros in the UWB. The high impedance section is folded producing multipath leading to the formation of notches. Transmission zero frequencies are at which the differential phase becomes equal to 180°. Simulations are carried out using ANSOFT HFSS and are fabricated using conventional FR4 PCB board. Prototype developed is tested and the obtained results are used to validate the simulations. Designed filter can be transformed into bandpass filter (BPF) in UWB by enhancing the widths of lower and upper rejection bands.