Compact Ultra-Wideband Bandpass Filter With Improved Upper Stopband Using Open/Shorted Stubs

A compact ultra-wideband (UWB) bandpass filter with improved upper stopband using open/shorted stubs is proposed in this letter. Seven transmission zeros in the upper stopband can be realized by different open/shorted stubs. The bandwidth of the UWB bandpass filter can be adjusted easily by changing the characteristic impedance of the open/shorted stubs. A UWB bandpass filter with 3-dB fractional bandwidth of 123% (0.5-1.9 GHz) is fabricated and measured. Good agreement can be observed between simulated and measured performances.