GB1012888A - Improvements in or relating to antenna systems - Google Patents

Abstract

1,012,888. Aerials. L. ROHDE, and H. SCHWARZ, [trading as ROHDE & SCHWARZ]. Sept. 6, 1962 [Sept. 6, 1961; Nov. 18, 1961], No. 34140/62. Heading H4A. An aerial array comprises a plurality of plane surface radiating elements 13, 14 symmetrically disposed in alternating sequence on the upper and lower surfaces of a dielectric support sheet 4 whose permittivity is substantially equal to that of free space. The support 4 is made of polystyrene foam and has the shape of a flat bottomed trough, the surface of the dielectric material 4 being hardened by a layer of synthetic material which closes the pores of the surface. The edges of the end of the trough are chamfered to co-operate with a similarly shaped reflector R which is parallel to the surface radiators and the conductive portions of the aerial system attached to the side of the support 4 facing the reflector R may be earthed by metallic supports located at the voltage modes. A protective covering 9 mounted around and spaced apart from the base of the support is provided to reduce the effect of ice formation and an earthed metal strip B, Figs. 2A and 2B, is mounted on the covering 9 parallel to the feeders 15, 16, 18, 19 interconnecting the radiating elements for protection against lightning. The radiating elements (which, as shown, are triangular but which may be rhombic, semicircular or Indian club-shaped) and their feeders are mounted in recesses 11, 12 formed in the upper and lower surfaces of the support. As shown, four pairs of elements (arranged as dipole groups) are symmetrically disposed with respect to the central feed point 17, each pair of elements being connected in parallel with the remaining pairs through strip feeders 15, 16, 18, 19, the feeders 18, 19 being wider than the feeders 15, 16 to effect matching. The elements and their feeders may be stamped from metal foil and attached to the supports by gluing or by means of flaps cut from the elements (Fig. 4, not shown) and pressed through the support sheet and then bent back or twisted (Fig. 3, not shown). Alternatively the elements and feeders may first be formed on thin printed circuit panels by etching or other known methods and these panels are then attached to the support by any of the methods referred to above. In a further embodiment (not shown) small holes are formed in the elements and their feeders which are held on the support by plugs of the support material oozing through the holes during the moulding process. Larger apertures 20, 21 formed in the moulding material are provided to facilitate connection of the central feeder point 17 to a printed circuit coupling unit (not shown) mounted on an internal stiffening rib of the support 4.