A triangular UWB bandpass filter with wide out-of-band rejection

A triangular shape for a ultra-wideband bandpass filter is presented and experimentally confirmed. The proposed structure can be roughly allocated in range of the 3.1 - 10.6 GHz UWB band. Because of including the interdigital feed lines and stubs at port positions, the wide-rejection stopband is higher than 20 dB in the band 10.8 to 32.8 GHz which is simply adjusting the lengths of them. Meanwhile, the value of compact size, good insertion and return loss and flat group delay can produce from the filter prototype.