Highly Selective, Multilayer wideband Bandpass Filter

This paper presents a new wideband, low-loss and sharp rejection Band pass filter which is implemented by using broadside coupled lines and stepped-impedance open circuit stubs. It is demonstrated that using stepped impedance open stub, controllable transmission zeroes are attainable. Transmission line model for proposed structure is introduced and detailed analysis is investigated. The goals of broad pass band and sharp rejection are achieved by choosing the impedances of transmission lines properly. Designed filter operates in 2-6 GHz with low insertion loss (less than 1dB) and high rejection in out of frequency band. The theoretically predicted performance is in good agreement with experimental results.