Apr 20th, 1:00 PM - 4:00 PM
Development of a Smart Crossed- Field Amplifier
Dr. Jim Browning
A Crossed-Field Amplifier (CFA) is a vacuum device that uses electrons to amplify a radio-frequency (rf) wave. These types of devices are used in radar systems and satellites. An experimental CFA apparatus, operating around 1 GHz, is being built to study the dynamic control of the device in order to improve performance (e.g., efficiency). The major components of the CFA include an rf slow wave circuit (SWC), an electromagnet, and a cathode. The cathode and SWC are fabricated using a Low Temperature Co-Fired Ceramic and thick film metal electrodes. The cathode consists of an array of gated field emitters that inject electrons between the SWC and the cathode. These electrons give energy to the rf signal traveling on the SWC. The electromagnet consists of two coils in a Helmholtz configuration that produces a 450 G field in the region where the cathode and SWC will interact. The methods of fabrication and measurements of the performance of these major components will be presented. The SWC performance is analyzed by measuring the characteristic impedance and attenuation versus frequency. The electromagnets generate a magnetic field proportional to the applied current, so the magnetic field strength and uniformity will be measured using a Tesla meter. The cathode structure requires fabrication of several thin ceramic layers with slits that allow injection of the electrons. The design, fabrication, and testing of this cathode structure will be presented.