GB574708A - Improvements in or relating to electron discharge devices - Google Patents

Abstract

574,708. Electric resonators. BLUMLEIN, A. D. Sept. 23, 1940, No. 14490. [Class 39 (i)] To reduce dielectric losses due to the inclusion in a hollow resonator of insulating material or of a part of the envelope of an electron discharge device of which the resonator forms part, the insulating material or part of the envelope is disposed so as substantially to coincide with a position of minimum field intensity in the resonator. As shown, a toroidal resonator 2 having a circular constriction 3 and apertures 4, which may be formed as grids, for the passage of the electron stream passes through the wall of the tubular envelope 1 and so includes a portion 1a of the latter. The resonator is so designed that in the case of each of the three portions lying respectively inside the envelope 1, between the envelope 1 and the constriction 3, and outside the constriction, the product of the equivalent lumped capacity and inductance of the inner surface is the same, in which case a position of minimum field intensity occurs in the neighbourhood of the part 1a of the envelope. Preferably, the inductance of the portion outside the constriction 3, and the inductance of the portion between the constriction and the envelope are respectively greater and less than that of the inner portion. Means is preferably provided to adjust the spacing between the walls at the constriction 3. Should the lines of force at the nodal region not be straight, the insulating material may be shaped to conform to them.