GB1367232A - Antenna means - Google Patents

Abstract

1367232 Aerials MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 13 June 1972 [14 June 1971 (3)] 27588/72 Heading H4A An aerial means of monopole or dipole type (Figs. 2 to 5, not shown) comprises one or two aerial conductors each consisting of a plurality of radiating linear conductors aligned serially, and each having an overall length not exceeding #/4 (#=wavelength at the lowest operating frequency). There are also provided substantially non-radiating parallel linear two-wire distributed constants transmission lines or stubs of lengths not exceeding #/4, each having one end thereof short-circuited and the other end thereof connected across adjacent ends of a pair of said radiating linear conductors, said stubs being disposed perpendicularly to the axis of the aerial conductor. The capacitive component of the aerial conductor impedance is compensated by inductive impedance components of the stubs, so that efficiency and bandwidth are improved. The stubs may be straight or folded or curved, and their lengths, or the spacings between their constituent conductors, may vary. Also, the lengths of the radiating linear conductors of an aerial conductor may vary (Figs. 7 to 9, not shown). In one embodiment, radiating elements 13, Fig. 10(c), and stubs 14 are formed by a printed circuit technique upon an elastic sheet 12 of insulating material, which is then inserted within a cylinder 11 of insulating material. The sheet 12 is retained within the cylinder 11 by reason of the elasticity of said sheet. A hole 15 in the cylinder provides an outlet for feeders. In another embodiment, an aerial means 20 comprises radiating elements 23, Fig. 11, and stubs 22, which are provided on the outside of a square bar 21 of insulating material. A conductive rod 24 is inserted in an axial hole in the bar 21, and is connected in parallel with the aerial means 20, so providing a dual frequency arrangement.