An Automatically Tunable Cavity Resonator System

A tunable cavity resonator is described that uses a feedback control system to alter its resonant characteristics in response to changes in its environment, without changing the physical dimensions of the resonator. Tuning wires inserted into the cavity are connected or disconnected to the cavity wall under the control of a binary algorithm that searches for desirable operating states from among a very large number of possible switch configurations. The ability of the cavity to be tuned in response to changes in either cavity loading or resonator size is investigated using simulations, and the feasibility of the system is thereby demonstrated. Measurements made using a laboratory prototype show that the cavity may be automatically tuned in response to changes in the properties of the materials within the cavity.