GB653464A - Directional beam aerial system with periodically varying radiation pattern - Google Patents

Abstract

653,464. Aerials. PATELHOLD PATENTVERWERTUNGS- & ELEKTRO-HOLDING, AKT.-GES. June 21, 1948, No. 16603. Convention date, July 14, 1947. [Class 40 (vii)] An aerial system, having a directional radia. tion pattern which performs a conical scanning motion, comprises a parabolic reflector from the apex of which extends a co-axial cable which supports and feeds a dipole located in the vicinity of the focus and means for causing the deflection of the dipole in a path about the focus. It is stated that this path may be elliptical whereby an elliptical-conical scan is performed. In Fig. 1, the co-axial cable K<SP>1</SP>, K<SP>2</SP> upon which is mounted the dipole D<SP>1</SP>, D2 and an associated reflector dipole, passes through the apex of the parabolic reflector R<SP>1</SP> and is deflected from the axis of the reflector so that its tip is located within a recess in a rotatable disc S. The axis of rotation of disc S coincides with axis of reflector R<SP>1</SP>, so that when the disc is rotated by motor M‹, the dipole D<SP>1</SP>, D<SP>2</SP> traces out a circular path about the reflector axis and the radiation pattern of the aerial performs a conical motion. In an alternative arrangement, Fig. 2 (not shown), an eccentrically loaded weight is attached to the end of the co-axial cable and is rotated rapidly by a shaft passing within the inner conductor of the cable and driven by a motor located behind the parabolic reflector. In these arrangements the co-axial cable is rigidly connected to the parabolic reflector and is itself flexible whereby the dipole may be displaced from the axis. In alternative arrangements, however, a rigid co-axial cable which is pivotally mounted, or supported by a resilient tubular element, upon a plate immediately behind the' reflector may be used. The Specification as open to inspection under Sect. 91 describes an arrangement, Fig. 3 (Cancelled), wherein an element R<SP>2</SP>, which is made of either dielectric or conducting material, is connected to a rotating shaft W<SP>1</SP> passing within the inner conductor K<SP>2</SP> of the co-axial cable, whereby the conical scan of the radiation pattern is obtained. In another arrangement, Fig. 4 (Cancelled) (not shown), an inclined reflecting surface is mounted at the end of the rotating shaft to obtain the desired conical scanning action. This subject-matter does not appear in the Specification as accepted.