High-dielectric constant stripline band-pass filters

High-dielectric constant (K=38) stripline was employed to realize selective bandpass filters. Seven-pole, gap-coupled filters centered at 6.0 and 8.0 GHz were designed for 140-MHz 3-dB bandwidths. The unloaded Q, choice of operating impedance, and the role played by higher order modes has been both analytically and experimentally considered. It has been found that experiment and theory are in good agreement, and allow the present results to be used in predicting performance levels for use in future designs. Miniaturization of high-performance filters has been demonstrated. Such filters are expected to find application in frequency multiplexers as well as in individual circuits, particularly with MMIC (microwave monolithic integrated circuit)-based systems.<>