GB592401A - Improvements in or relating to wave guide systems for ultra-high frequency electromagnetic waves - Google Patents

Abstract

592,401. Discharge apparatus; wave-guides. WESTERN ELECTRIC CO., Inc. Jan. 13, 1944, No. 709. Convention date, May 3, 1941. [Classes 39 (i) and 40 (v)] An electron discharge device incorporated in a hollow tubular wave-guide 1, Fig. 1, comprises a source of electrons such as filament cathode 5 extending longitudinally within a portion 3 of the guide which is so constricted that its cutoff frequency is only slightly below the operating frequency. This enables the cathode to be made of considerable extent without exceeding a quarter of the effective wavelength in the constricted portion. The cathode 5, Fig. 2, is flanked by ribbons 6, 7 which are connected to it so as to equalize the direct current potential ; one of them acts as a return lead for the heating current. The constricted portion 4 follows a contour roughly orthogonal to the lines of electric force of an H1 wave in the unconstricted guide, but is shortened along the long axis so as to give the desired increase in cut-off frequency. The device of Figs. 1 and 2 acts as a negative resistance diode as in Specification 516,750 for oscillation, amplification, modulation or detection, the transit time being adjusted to an integral number of cycles plus a quarter-cycle. Iris diaphragms are provided on either side of the device in the unconstricted guide. In another form, the constricted guide forms the anode structure of a magnetron. In the equivalent of, a four-split anode magnetron, the contour may follow one of the dotted lines 22, 23 or 24, Fig. 5, which are orthogonal to the lines of electric force (full lines) of an H. wave. The Specification as open to inspection under Sect. 91 comprises also forms in which an electron beam from gun 27, Fig. 6 (Cancelled), is fired through aperture 26 transversely across a wave-guide 1, which may be circular, square, triangular or sectoral, the beam following the straight line of electric force in an H, wave. In a triode arrangement for transferring energy between juxtaposed rectangular waveguides 45, 46, Fig. 12 (Cancelled), the cathode 51 and anode 55 are insulated platesin the outer walls of the guides and the grid 50 stretches across an aperture in the common wall. Tuning pistons 57, 58 are provided. In a frequency multiplier, the output wave-guide 60, Fig. 14 (Cancelled), is made narrower than the input guide 59, so that it will only transmit harmonics of the input frequency. This subject. matter does not appear in the Specification as accepted.