Abstract: A tuning head for use with a variable capacitor includes a coupler having a gap, a first optical fiber operatively coupled to the coupler, and a second optical fiber operatively coupled to the coupler. The first and second optical fibers are optically coupled across the gap when the gap is not obstructed. The tuning head further includes an obstruction member that is movable with respect to the coupler and is adapted to fit within the gap to selectively obstruct said optical coupling of said first and second optical fibers. A movement mechanism is also provided to create relative motion between said obstruction member and said coupler.

Abstract: A sealed variable capacitor assembly including a generally cylindrical metallic enclosure in which fixed and movable interleaving capacitor plate sets are contained, the movable set being varied by axial translation thereof by means of a leadscrew arrangement within a bellows which effects sealing while permitting the required axial translation of the movable plates. Spring fingers connected to the moving plate subassembly engage at least a portion of the inside surface of the metallic enclosure slidably. Accordingly, the RF current path from the movable plates largely bypasses the bellows permitting the latter to be of a relatively small diameter. The mounting of the fixed plate set is by means of a rigid feedthrough insulator mounted through the end-wall of the enclosure opposite the end from which the aforementioned lead-screw extends.

Abstract: A "fixed" vacuum capacitor assembly in which first and second sets of interleaved, substantially concentric, capacitor plates are held between opposing end-bell assemblies. A trimmer capacitor including third and fourth sets of capacitor plates, an axial leadscrew assembly and a vacuum sealed axially extendable bellows are emplaced substantially coaxially within the first and second capacitor plate assembly. The third and fourth capacitor plates are variably interleavable in accordance with the leadscrew setting and these third and fourth plate sets together with the leadscrew bellows assembly occupy substantially the same axial dimension, between the end-bell assemblies, as is occupied by the first and second plate sets.