Parasitic coupled line for notch implementation in UWB BPFs

A compact microstrip ultra-wideband (UWB) bandpass filter (BPF) with a narrow notched band in the UWB passband is presented, for use in wireless communication applications. The narrow notched band was introduced by using a new technique which involves embedding a parasitic coupled line to the UWB BPF, in order to reject any undesired existing radio signal which may interfere with the determined UWB passband. The notched band can be easily generated and set at any desired frequency and can be controlled by varying the length and the width of parasitic coupled line. The design is successfully realized in theory and verified by electromagnetic (EM) simulation and the experiment.