GB661240A - Improvements in folded-dipole aerials - Google Patents

Abstract

661,240. Aerials. PHILIPS ELECTRICAL, Ltd. April 13, 1949 [April 16, 1948], No. 10018/49. Class 40 (vii). An aerial system comprises at least two radiators (three, as shown, 1, 2, 3) which are parallel, of equal length, and closely spaced, the adjacent ends are electrically connected as by members 5 and 6 and the aerial is fed at a gap 4 in one of the radiators, the feed line being connected to one side of the gap and led in an insulated manner through the interior of the part of the radiator on the other side of the gap and to the centre of an uninterrupted radiator whence it is led out at right angles for a distance of at least #/4, as the central conductor 7 of a coaxial line whose outer conductor 8 is connected to the uninterrupted radiator round the edge of the hole 9, through which the conductor 7 passes. The aerial system is substantially symmetrical in a way not dependent on frequency and can thus be used over a frequency band without substantial parasitic current flow along the exterior of the coaxial line 7-8 as a result of the different capacities between the aerial elements and the sheath 8. The radiators may be approximately #/2 long at the centre of the wavelength range covered and are preferably tubular.