Abstract: An inhomogeneous ceramic dielectric microwave RF TEM resonator filter having a plurality of unplated notches in the ceramic for enhancing direct inter-resonator coupling. The filter is implemented without the lumped coupling capacitors which are typically associated with each resonator of a TEM resonator filter. Furthermore, the launching resonators which are typically used to couple in and out of the filter are eliminated by using coaxial probe capacitors inserted in each of the end resonators. The non-end resonators can be made to look as long as the end resonators, with probes therein, by including a conductor pad disposed upon the block top surface and connecting the internal plating of the non-end resonators.

Abstract: A low-loss bandpass microwave filter is disclosed which enables filter size reduction in the frequency range of 1-5 GHz. The filter includes a main ceramic body member which is notched or drilled and coated over all exposed surfaces except for opposite end portions. Coupling terminals are attached to the opposite end portions to provide microwave input and output coupling to the filter.

Abstract: An improved coaxial K inverter is disclosed for use in forming coaxial microwave filters. A filter including a K inverter may be constructed using at least one resonator including a conductor terminated at one end by an apertured plate and coaxially surrounded by a dielectric material. The resonator may be enclosed in a conductive housing electrically coupled to the apertured plate and capacitively coupled at the other end of the conductor to an input terminal for receiving microwave energy. A second conductor terminated at one end in a second apertured plate is positioned within the housing such that the apertured plates are adjacent one another forming a K inverter. The other end of the second conductor is capacitively coupled to an output terminal forming the electrical output from the filter.