Eigen-mode analysis of a novel three-mode microstrip/slot-line resonator and the development of a compact bandpass filter with multiple transmission zeros and wide stopband property

Summary form only given, as follows. A novel three-mode resonator is proposed, which consists of a parallel-coupled microstrip-line resonator embedded with a slotline resonator. Resonance properties of these three modes are analyzed by using an electromagnetic simulator. Four transmission zeros are produced because of multi-paths between input/output lines formed by the three modes and the source-load coupling. A circuit model is proposed and a compact bandpass filter with sharp skirt property and a wide stopband is developed.