A New Directional Filter Design

摘要

An elliptic circuit for cascaded directional filters was proposed for designing miniature combiners with very wide bandwidth and very tight shape factors for wireless base station applications. A miniature combiner was designed based on the proposed elliptic circuits using ceramic resonators with unloaded quality factor of around 800. EM simulation with HFSS software proved the design concept. A prototype unit with a package size of 127 mm x 59 mm x 14 mm was built. The measured minimum channel isolation was more than 30 dB, and the maximum channel insertion loss was less than 0.8 dB.