A novel trap mechanism in coaxial-coupled waveguide filters

We propose here an unprecedentedly new design idea for coaxial-coupled cutoff-waveguide filters. Contrary to ordinary design approach, in which the coax-waveguide transition is utilized only as an impedance-invertor circuit, the proposed idea utilizes the transition as a structure that serves both as the impedance-invertor circuit and as the high-frequency-trap circuit. These new features have been derived theoretically anid verified by experiments that we took.