Triangular Patch UWB Filter with a Band-Notched Characteristic

Since the US Federal Communications Commission (FCC) released the unlicensed use of the ultra-wideband (3.1-10.6 GHz) spectrum for indoor and hand-held systems in Feb-2002[1]. Recently, the development of new UWB filters has increased via different methods and structures [2]??[5]. In [2] an initial UWB filter is presented by mounting a microstrip line in a lossy composite substrate to attenuate the signal at high frequencies, and the reported insertion loss is higher than 6.0 dB. In [3] a novel microstrip UWB BPF has been constructed by using a circular ring resonator structure in cascade and the reported insertion loss is 0.58dB in the passband, integration of multiple-mode resonator (MMR) with two coupledlines for the UWB passband [4].