An ultra wideband microstrip bandpass filter with wide stopband using SIR and DGS

摘要

In this paper an ultra wideband microstrip Bandpass filter is proposed using stepped impedance resonators (SIR) and defected ground structures (DGS). This band-pass filter is designed to operate within the Ultra Wide Band frequency range from 4.0 GHz to 11.0 GHz with 7.0 GHZ bandwidth and centre frequency at 7.5 GHz. This prototype filter is designed on RT/Duroid 5880 substrate of thickness 0.787mm with dielectric constant 2.2. The filter is simulated and optimized using Zealand IE3D simulation software v14.0. The passband of the filter has five transmission poles. Insertion loss within the passband is better than -1.5dB and the return loss is kept less than -20dB and a total fractional bandwidth of 93.33% is obtained. The prototype built can be used in UWB communications or localization systems.