GB801200A - Improvements in or relating to a self-supporting aerial - Google Patents

Abstract

801,200. Aerials. COLUMBIA PRODUCTS CO. May 4, 1956 [July 14, 1955], No. 13946/56. Class 40 (7). A resonant aerial suitable for use on a motor vehicle comprises a conductive core embedded in an insulating rod comprising glass fibres and a bonding agent therefor. The aerial is made flexible and resilient and is capable of withstanding considerable impact shocks. Moreover, as the ratio of glass fibres to bonding agent is made high the conductor coating has a high dielectric constant and the aerial length for a given operating frequency is less than that of a simple resonant conductor not encased in dielectric. Preferably the conductor 11 is first surrounded by a plurality of longitudinally extending glass fibres 10a acting as tension members and the whole then spirally wound with further glass fibres 10b forming an impact resisting layer. All the fibres are coated with a suitable bonding agent, for example a resin of the polyester type, and the assembly may be wound with tape to retain the desired arrangement during curing of the resin. In order to make the dielectric constant of the insulating material high, it should consist of approximately 70 per cent fibre glass and 30 per cent bonding agent by weight. In order to raise the dielectric constant of the material further the bonding agent may comprise resin loaded with materials such as titanium dioxide or barium titanate. The conductive core 11 may be attached to a metal socket at one end of the aerial and may comprise solid or stranded wire or a group of spaced wires where a broad bandwidth is desired. The lengths of the longitudinally extending glass fibres may be graded to give the tapered shape shown and the free end of the aerial may terminate in a ball.