GB758794A - Aerial systems - Google Patents

Abstract

758,794. Aerials. BELLING & LEE, Ltd. May 31, 1955 [Aug. 23, 1954], No. 24467/54. Class 40 (7). A wide-band aerial array comprises at least two pairs of similar folded dipoles, parallel to one another and each pair perpendicular to an axis extending through their centres. The dipoles of a pair are separated by a distance of quarter of a wavelength and have their feedpoints joined by a transmission line with a characteristic impedance equal to the dipole impedance; the feeder is connected to one end of this line. The axes of the pairs are all parallel and separated one from another by half a wavelength. In the embodiment shown, two pairs of folded dipoles 10, 11 and 12, 13 disposed side-by-side are used, each pair being coupled by a quarter-wavelength transmission line 14 or 15 of the appropriate impedance. The axes of the dipole pairs are separated by half a wavelength and feeders 16 and 17 of an impedance half that of lines 14 and 15 are coupled as shown and connected to the main feeder junction-box 18. To support the array the centre points of the dipoles 10 and 12 remote from the transmission line may be joined by a support tube 19 to which is also joined a tube 20 carrying the junction-box 18. The array is directional in the direction indicated by the arrow X and director and reflector parasitic elements 22, 23, 24 and 25 may be added to increase the directivity if required. The orientation of the folded dipoles may be changed so that they all lie in the same plane.