Tubes for dielectric heating at 915 megacycles

Dielectric heating can be much faster at microwave frequencies. Because leakage radiation is large enough to interfere with communications, heating is best done at assigned frequencies. The bands at 915 and 2,450 megacycles are most useful. An industrial magnetron oscillator generates 5 kw at 915 megacycles. The tube and associated control circuits are described. Apparatus for heating dinners and plastics has been constructed using this tube. Experimental magnetrons give 30 kw at 1,000 megacycles.