GB494722A - Improvements in or relating to methods of generating ultra short electro-magnetic waves - Google Patents

Abstract

494,722. Discharge apparatus; directive wireless systems. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE. April 27, 1937, No. 12056. Convention date, April 27, 1936. [Classes 39 (i) and 40 (v)] A method of generating very short waves consists in impulsively exciting to oscillation rod or strip structures which are capable of resonance, by electrostatic influence or electromagnetic induction resulting from the approach to or recession from said structures of electrons freely and progressively moving past them. The electrons are emitted impulsively from a suitably controlled cathode which may be a spark discharge ; or a constant source of electrons may excite an impulsively controlled source of secondary electrons. In. one form a number of wholewave length dipoles are arranged in three straight lines emanating from the cathode ; the spacing of the dipoles decreases as the electron velocity in the beam falls. The dipoles are all tuned to a multiple of the impulse frequency. In the form shown in Fig. 6, the structures are arranged at intervals of half a wave-length along a line terminated by a dipole D. The cathode K is in the middle of the line and anodes A at each end ; the physical distance of the structures decreases towards the ends. In Fig. 7 electron beams from cathode K are bent by a magnetic field so as to excite the circularly arranged structures S. These may radiate individually, giving a circularly polarized wave, or may be connected by a line as in Fig. 6. The field is such that electrons cannot escape between the plates H unless an auxiliary voltage is applied between them, to obtain the necessary impulsive emission. The structures are all enclosed in evacuated vessels. The Specification as open to inspection under Sect. 91 includes also arrangements in which (1) an electron beam excites a number of equally spaced dipoles tuned to different frequencies, Fig. 6 (Cancelled) (not shown) ; (2) secondary electrons released by a spark discharge excite a number of negatively biassed structures arranged at random in an evacuated space, Fig. 9 (Cancelled) (not shown). This subject-matter does not appear in the Specification as accepted.