Multimode injected-beam crossed-field amplifier for coherent airborne radar

Injected-beam crossed-field amplifiers (IBCFAs) are admirably suited for multimode transmitting amplifiers because beam current can be continuously varied from zero to maximum with good beam focusing and with high efficiency over a substantial range of beam currents. The range of pulse-up while maintaining high efficiency can be greatly extended by changing magnetic field levels and applied voltages at the same time. Further improvement in pulse-up operation is made possible by depressed collector techniques. Measurements of IBCFAs designed for 10 dB pulse-up in X-Band from 1.5 to 15 kW peak power output over a 10% bandwidth with low phase noise are presented, including the effects of the depressed collector and magnetic field switching.