Abstract: A negative resistance generator includes first and second terminals; first and second inductors connected in series between the terminals; and a semiconductor amplifying device having a first control electrode connected to the first terminal and a first active electrode connected to the second terminal and a second active electrode connected to the junction of the inductors. When employed in an active filter resonator a first variable capacitor is interconnected with the inductors for setting the resonant frequency of the resonator. The resonators may be combined in an active filter with a transmission line where each of the resonators is interconnected to the line by decreasing resistance from the input to the output in order to balance the rf currents to which the resonators are subjected.

Abstract: A thin film structure is provided with the capability of low-power laser tuning and trimming. Trim windows in a plated ground plane are incorporated to allow automated tuning procedures using relatively low-power lasers. The trim windows are conductive, but the heavier layer of plated copper is omitted from those areas, leaving only the titanium/evaporated copper/ gold layers. The method can also provide for areas of bare substrate if desired.

Abstract: Stripline filters and the like have one or more elongated resonator conductors positioned on a dielectric substrate which is backed by a ground plane conductor, with the response frequency being dependent primarily on the length of the resonator. A wide apron conductor is connected to the grounded end of the resonator and to the ground planes. The resonator and apron can be formed by use of a mask such that errors in alignment of the mask do not change the length of the resonator or the point of connection to the grounding apron. The apron, because of its width, has low transmission line impedance to the ground plane which is not changed by changes in configuration or position of the mask, so that it effectively grounds the resonator at the end thereof connected to the apron. A second dielectric substrate backed by a ground plane conductor may be placed on the resonator conductor.

Abstract: Stripline filters and the like have one or more elongated resonator conductors positioned on a dielectric substrate which is backed by a ground plane conductor, with the response frequency being dependent primarily on the length of the resonator. A wide apron conductor is connected to the grounded end of the resonator and to the ground planes. The resonator and apron can be formed by use of a mask such that errors in alignment of the mask do not change the length of the resonator or the point of connection to the grounding apron. The apron, because of its width, has low transmission line impedance to the ground plane which is not changed by changes in configuration or position of the mask, so that it effectively grounds the resonator at the end thereof connected to the apron. A second dielectric substrate backed by a ground plane conductor may be placed on the resonator conductor.