GB576444A - Improvements in methods of wireless beam propagation - Google Patents

Abstract

576,444. Directive wireless signalling. DOWSETT, H. M. April 18, 1941, No. 5026. [Class 40 (v)] Radiation from a dipole is reflected as a beam of rotational symmetry and restricted spread to a terminal reflector which gives it the required spread. The reflector system may be regarded as a radio link between two sections of the transmitter. In Fig. 1, the dipole AOB is at one focus and along the axis of a combined spherical and elliptical reflector c, a, b. Radiation falling on the spherical part ca is reflected back so as to be in phase with the radiation falling on the elliptical part a, b, which is focused at P and collected by a double elliptical reflector f, d, e which focuses it at Q and R. In the final reflector g, h, k, the radiation is brought to a focus at S and then diverged at an angle of 45 degrees. In Fig. 2, the radiation from AOB falling on the spherical part ac is reflected back so as to be in phase with that falling on the elliptical part ab, which is focused at P and received by a parabolic reflector dd which transmits it as a hollow cylindrical beam X passing through an aperture in the back of reflector ac. The direction of the beam may be varied by a plane reflector, and the generator and a tube containing part of the reflecting system may be placed underground, the final reflector being above ground level. Communication between the two ends of the link may be effected with the aid of pick-up receiving coils inserted in the diverging beam from the terminal reflector, Fig. 4 (not shown).