Improvements in and relating to high frequency electrical oscillators

588,917. Magnetrons. WRIGHT, C. S., RANDALL, J. T., SAYERS, J., BOOT, H. A. H., and DAWTON, R. H. V. M. Dec. 17,1941, No. 16317. [Class 39 (i)] A magnetron of the type described in Specification 588,185 is coupled directly to. a hollow conducting wave-guide, without the interposition of any other kind of transmission line. The cathode K, Fig. 1; is surrounded by a number of identical resonators R machined out of a solid block and opening into the cathode space C. Both the resonators and the cathode space open at their ends into end spaces 1, one of which has a tubular opening 3, covered by a glass cap S, and engaging the wave-guide 4. Antennµ 2 are connected to parts of the resonator system, vibrating in opposite phase. These antennµ may be the straps used, in Specification 588,916, to keep the resonators in unison ; or a single radiating grid, backed by a reflecting plate, may be used. The waveguide may be at right angles to the axis of the magnetron and communicating with both end chambers, each of which then contains antennµ. In a modification, energy is radiated from an aperture 12, Fig. 5, in one of the resonators, direct into the wave-guide 4. A tapered horn 13 is provided. If the wave-guide is rectangular, the aperture 12 would be a slot parallel to the long dimension of its cross-section. The glass seal S may be dispensed with if the guide is evacuated. The arrangement is suitable for both transmission and reception. Specification 540,232 also is referred to. According to the Provisional Specification, the arrangement may be used with velocity-modulated tubes.