Ultra-wideband bandpass filter using novel CMRC with improved out-of-band performances

An improved multiple mode resonant (MMR) ultrawideband (UWB) bandpass filter is proposed using a novel rectangular slit compact microstrip resonant cell (CMRC). The CMRC is formed by perforating on the central section of the MMR, which make the both structures incorporate into one successfully. Combining the CMRC lowpass filter and slow wave characteristics, the filter has widened stopband characteristic and sharpened rejection skirts outside the UWB passband, and it has also compact size. A demonstration filter was designed, fabricated and measured. Good agreement between experimental and simulated results is achieved.