Abstract: An RF tuneable resonator wherein RF energy is applied to a helical coil and he resonant frequency of the resonator is varied by utilizing a pair of axially moveable dielectric cylinders. One dielectric cylinder surrounds the helical coil and the other dielectric cylinder is positioned within the coil. Both dielectric cylinders are individually actuated along the axis of the coil.

Abstract: At least three pairs of opposing electrodes on the two major faces of a poelectric or electrostrictive transducer element having a gap which is adapted to change in response to selected control voltages applied across the three pairs of electrodes. The pairs of electrodes are electrically insulated from one another and one pair of electrodes covers substantially one half of the major faces across from the gap, while the other two pairs of electrodes are disposed on the major faces of the transducer adjacent the gap and respectively covering substantially quarter sector portions of the transducer surface. By the mechanical bonding of electrical switch contacts for example to the opposing end faces at the gap, switch actuation is provided by the application of control voltages across all three pairs of electrodes, causing the gap to diminish and thereafter shorting the pairs of electrodes or applying a reverse control voltage to widen the gap.