Planar SIR microwave bandpass filter using high-permittivity ceramics

High-permittivity dielectric ceramic materials have been applied in the fabrication of a planar stepped-impedance resonator (SIR) microwave bandpass filter. The input / output ports of the filter are formed with transmission lines directly tapped to the resonators. The admittance matrix for the equivalent circuit of the filter. has been derived and transformed to the scattering matrix to initially determine the required spec. Losses and other EM effects are taken into account to further modify the actual dimension of the designed filter. The designed structures are simulated using an IE3D simulator. Fabricated filters are measured by an HP8510B network analyzer: Sample results of the filter performances demonstrate responses in good agreement with the computer simulations. (C) 2000 John Wiley & Sons, Inc.