A Novel Ultra-Wideband (UWB) Bandpass Filter (BPF) With Pairs of Transmission Zeroes

A novel, compact, and highly selective ultra-wideband bandpass filter was developed on a microstrip line and presented in this letter for use in wireless communication applications. The basic filter is composed of five short-circuited stubs separated by nonredundant connecting lines that contribute to the filter selectivity as well. In addition, a cross-coupling between the feed lines (input and output) was introduced which generated new pairs of attenuation poles at each side of the passband. As a result, the filter exhibited extremely sharp rejection skirts around the target passband without the need for increasing the number of transmission line sections. The filter was successfully designed, simulated, and fabricated. The theoretical, EM-simulated, and experimental performance is presented in this work where excellent agreement between them was obtained