Design of Wideband Lumped Crossovers With Resonator-Loaded Window Shape Structure

摘要

This letter presents a wideband lumped crossover based on the resonator-loaded window shape structure. To enhance both the matching bandwidth and the isolation of the adjacent ports, four shunt LC resonators are mounted at each port junction of the window-shaped topology. Based on the even-odd mode theory, every lumped element of the designed crossover could be derived according to the transmission conditions at the operating frequency. Two additional reflection zeros are introduced for the enhancement of the matching bandwidth, while one additional transmission zero is generated to improve the isolation. Finally, a prototype of the proposed wideband crossover is designed and fabricated at 1.0 GHz. The measured results show that the fractional bandwidth of 15-dB isolation is 32.5% and the 15-dB matching bandwidth (return loss) is 49%.