Uwb Bpf using Quad Section Stepped Impedance Resonator

Abstract

Ultra wide band (UWB) frequency range is from 3.1 to 10.6 GHz with a bandwidth of 7.5 GHz. UWB bandpass filter(BPF) is an essential component of any UWB communication system. Design of UWB BPF with extremely high bandwidth is a challenge task. In this paper a simple method is developed for the design of UWB BPF. A quad section stepped impedance resonator (QSSIR) is used as the basic element of the filter. QSSIR has four impedance sections connected in cascade. Ultra wide bandwidth is realized by appropriately selecting impedance ratio and electrical length ratio of the SIR. Two transmission zeros are introduced in the insertion loss response by folding the QSSIR. Designed filter has bandwidth extending from 3.73 to 9.93 GHz with a fractional band width (FBW) of 91% and center frequency 6.83 GHz. There are five transmission poles in the obtained frequency response. Simulation is performed using ANSOFT HFSS. Designed filter was fabricated using FR4 substrate. Test results are found to be in good agreement with simulations. Proposed filter has a simple planar structure. Fabrication is easy. It can be used in UWB systems as band pass filter