Fabrication and test of a high power s-band metamaterial backward-wave oscillator

This paper presents the experimental demonstration of a high power backward-wave oscillator (BWO) that uses a negative index mode in a waveguide filled with a metamaterial (MTM). The MTMBWO uses a 500 keV, 80 A electron beam. Initial tests of a 352 mm long metamaterial structure generated 40 W of power at 2.83 GHz. The measured frequency vs. electron beam voltage is in very good agreement with theory. Tests of a longer structure designed to produce over 1 MW of microwave power are scheduled to begin in Spring 2015. To our knowledge, this is the first experimental demonstration of a high power microwave source utilizing an MTM structure.