Air dielectric variable capacitor utilizing a stator formed as part of

Abstract

A new low profile miniaturized air dielectric variable capacitor for use in hybrid circuits. A very cost effective, low priced variable capacitor that combines precision with a low profile is disclosed for use in hybrid circuits and other applications where space requirements are tight. The new capacitor uses a unique design to achieve an extremely low profile, less than 0.127 inches, for varying capacitive ranges. The new design is achieved by creating the stator as part of the circuit layout or design. The stator is actually formed on the surface of the substrate by a thick film metallization or by copper etching and one or many capacitors can be formed as part of the circuit layout. Thereafter, a metallic conductive housing, internally threaded, is positioned over the stator. Internal to the housing is an externally threaded rotor having an adjusting knob or screw extending through the housing. With a thread density of one hundred twenty-eight turns per inch on the housing and the rotor, four complete revolutions can be achieved for purposes of adjustability of the capacitance. With housings of diameters varying between less than a quarter of an inch to a half inch tunable capacitive ranges can be achieved between one and nine picofarads. Because the design of the capacitor is leadless extremely high frequencies can be utilized up to those in the gigahertz range.