A Coplanar Stripline Ultra-Wideband Bandpass Filter With Notch Band

In this letter, a design of a compact coplanar stripline ultra-wideband bandpass filter with a narrow rejection band is reported. The filter characteristic is obtained by using stepped impedance open-circuited series stubs. It is shown that the rejection band can be placed at a desired frequency by tuning the width of the high impedance section of the series stub. Full-wave simulated and experimental results of a filter prototype are presented.