Title :
Equivalent-circuit representation and explanation of attenuation poles of a dual-mode dielectric-resonator bandpass filter
Author :
Awai, Ikuo ; Kundu, Arun C. ; Yamashita, Takeharu
Author_Institution :
Dept. of Electr. & Electron. Eng., Yamaguchi Univ., Ube, Japan
fDate :
12/1/1998 12:00:00 AM
Abstract :
A λ/4 rectangular-waveguide resonator of square cross section filled with high-permittivity ceramics has two degenerate lowest modes. A dual-mode bandpass filter based on this structure is studied, focusing on the attenuation poles at both sides of the passband. It is described how to achieve capacitive and inductive coupling between dominant modes of a resonator of square cross section. An equivalent-circuit model is proposed, including mode coupling, excitation from the external circuit, and direct coupling between input/output (I/O) electrodes. Equivalent-circuit parameters are measured and their validity is verified using simulated results. Appearance and annihilation of the attenuation poles are successfully explained by the proposed model, and attenuation pole frequencies are controlled by shifting the I/O electrode transversely
Keywords :
band-pass filters; dielectric resonator filters; dielectric-loaded waveguides; equivalent circuits; microwave filters; passive filters; poles and zeros; waveguide filters; I/O electrode transverse shifting; attenuation pole frequencies control; attenuation poles; capacitive coupling; degenerate lowest modes; dielectric-resonator bandpass filter; dominant modes; dual-mode DR bandpass filter; equivalent circuit representation; equivalent-circuit model; equivalent-circuit parameters; high-permittivity ceramics; inductive coupling; mode coupling; rectangular-waveguide resonator; square cross section; Attenuation; Band pass filters; Coupling circuits; Dielectrics; Electrodes; Equivalent circuits; Finite difference methods; Passband; Resonant frequency; Time domain analysis;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
