Control of Attenuation Pole Frequencies and Miniaturization of a Two-Pole λ/4 Tem-Mode Planar Dielectric Waveguide Bandpass Filter

Theoretical explanation for the appearance of attenuation poles at the both sides of the passband of a two-pole λ/4 TEM-mode planar dielectric waveguide bandpass filter is lucidly described with equivalent circuit representation. Control of the appeared attenuation poles is described theoretically and justified by experimental result. Keeping the electrical performance of the BPF almost unchanged, the miniaturization technology with increased mechanical strength of the planar BPF structure is proposed and verified by experiment.