Low cost approaches to crossed-field amplifier development

In some circumstances, there are cost and system advantages when a phased array radar makes use of an RF source driving each individual antenna element. Sources with a power output of a few kW, 10% duty capability, approximately 20% bandwidth and high efficiency are of interest. To be attractive, such an RF source should cost less than a few hundred dollars. Experimental data were obtained on a demountable CFA system in which circuits, soles and electron guns could be modified as needed. BeO supported brazed circuits and printed meanderlines were used. The sole materials ranged from low secondary emitters, such as molybdenum, to high secondary emitters, such as thin films of oxides of Be alloys. The beam current could be varied from full injected beam operation at 1 ampere to partial injected beam operation at 0.01 ampere. In the latter case, secondary emission from the sole built up the beam current to several amperes.