GB592256A - Couplings means for electrical cavity resonators - Google Patents

Abstract

592,256. Thermionic valves; coaxial line resonators and circuits therefor. WESTERN ELECTRIC CO., Inc. Sept. 9, 1943, No. 14842. Convention date, April 17, 1942. [Classes 40 (iii) and 40 (v)] A coupling between a pair of cavity resonators comprises a conductor extending through juxtaposed apertures in the resonator walls so as to link with the electromagnetic fields in the resonators. The conductor is coupled to the resonator walls at a point removed from the apertures and provided with tuning means. The cavity resonators may be contiguous and have a common wall containing an aperture through , which the conductor extends linked with fields on opposite sides of the wall. The invention is primarily for feeding back a controlled portion of the output energy of a highfrequency discharge device incorporated in the resonator structure to produce regeneration, degeneration or neutralization. Fig. 1 shows resonators 34, 38, 36, 38 with a common wall 14 provided with a slot 64 through which extends the loops 76, 78. The input 48 may be applied through a coaxial line, as shown, or through coupling loops and the load 58 may be similarly coupled to the output. Associated with the resonators is a grounded-grid triode in an evacuated envelope 10 consisting of a plate cathode 20, a mesh grid 28 and a plate anode 30 mounted in supporting discs from the wall of the resonator structures. Rings 40, 42 and 44, 46 respectively provide insulation, so that anode and grid bias potentials may be applied. The length of the coupling loops may be varied by short circuiting discs 72, 74 and the loops size by sliding the loop bodily in the slot 64 to vary the coupling. Alternatively, capacitive termination may be used for the loops. Fig. 7, (not shown), or a single line, Fig. 8, (not shown), may be used. Fig. 9 shows a schematic arrangement in which internal tuning is effected either wholly or partially by screws 108. The position of the current lead in the loop may be varied by the relative displacement of the short circuiting discs, Figs. 5 and 6, (not shown), and the tuning of the lines may be resistive, i.e. to halfwave length, or capacitive, i.e. to greater than half-wave length, or inductive, i.e. less than half-wave length. Adjustment for neutralization may be effected by feeding energy to the line 56 and adjusting until minimum output is obtained over the line 50. Fig. 2 shows a modification in which a tetrode having a screen grid 90 is used, similar arrangements of rings 94 being provided for applying the screen grid potential.