Alternative Architectures for Narrowband Varactor-Tuned Bandpass Filters

摘要

A unique design approach for narrowband tunable bandpass filters is presented which focuses on engineering the tuned center-frequency dependence of the coupling coefficient between adjacent resonators. New architectures are presented and equations for the coupling coefficient are derived from energy expressions. A microstrip prototype with independentlytunable center frequency and bandwidth was built and tested and exhibits excellent performance.