GB749755A - Electric gaseous discharge waveguide switching device - Google Patents

Abstract

749,755. High-frequency discharge apparatus. STANDARD TELEPHONES & CABLES, Ltd. Feb. 18, 1953 [Feb. 18, 1952], No. 4536/53. Class 39 (1). [Also in Group XL (b)] A wide-band ultra-high-frequency switching device comprises a number of discharge tubes each traversing a resonant structure within a waveguide. The structures comprise inductive irises 4, 5, Fig. 3, and one or two capacitative posts 6, 7 arranged in the same plane. Passing through each post or pair of posts is a discharge tube 10 comprising a cathode 11 and an anode 12. Isolating resistances connecting the anodes 12 to earth ensure that all the tubes, which are connected in parallel to the same source, fire at the same time. The tubes contain rare gases, i.e. xenon or argon, at a pressure of 10 mm. Hg. to which may be added small amounts (less than 0.1 per cent) of water vapour in order to decrease the de-ionization time. Power is derived from a high-voltage D.C. or A.C. (including R.F.) source. A keepalive voltage is applied to the tubes or, for the same purpose, the tubes may contain a radioactive or photo-emissive internal source. The electron density at the point where the tubes intersect the guide may be increased by decreasing the internal diameter at this point or by providing at the required point in each tube an axial rod 22, Fig. 3, of dielectric material. This rod may be supported by the anode structure. In order to obtain greater interaction between the electromagnetic energy and the gas discharge the diameter of the tubes 24 may be increased as shown in Fig. 4a. In the construction of Fig. 5, a circular waveguide 33 having segmental iris members 35 and posts 34 is traversed several times by a discharge tube 38 of serpentine form which passes through the posts 34. A modified form of tube, Fig. 7, has a gas reservoir 40 with two limbs 41, 42 and two pairs of electrodes 45, 48.