Dr. Jim Browning
A magnetron is a vacuum device that uses the interaction of electrons and an electric field to generate microwaves. Magnetrons are often used for radar systems. Current magnetrons create electrons by heating a tungsten wire to the point that it emits electrons. These systems waste large amounts of energy and are difficult to control. A shielded cold cathode magnetron is a new magnetron design that has the potential to greatly improve the magnetron’s efficiency. These new magnetrons utilize arrays of gated field emitters to inject the electrons into the electric field. These field emitters must be protected from electron bombardment inside of the cavity, so a ceramic structure is incorporated into the design. The field emitter structure consists of emitter tips paired with gates; the electron motion is controlled by a pusher electrode. These emitter gate pair arrays can be individually addressed, thereby allowing control of electron injection. The ceramic structure is fabricated using a Low Temperature Co-Fired Ceramic and thick film metal electrodes. This structure is designed to shield the emitters from back bombardment by electrons and ions. Performance can be measured using segmented collectors and energy analyzers. The results from the design, fabrication, and testing of a shielded cold cathode test structure will be presented.