Folded dipole aerial giving circular polarisation - supply wire short relative to two excited half plates to provide aerial short circuited at its ends

摘要

A circular polarisation doublet plate aerial comprises two separated coplanar half plates (1, 2) axially aligned and formed on one side of a printed circuit board. The plates have a large width. On the opposite side of the board a narrow band line (11) is formed on a parallel axis and is excited symmetrically from two coaxial lines (16, 17). The doublet is effectively short circuited at its extremities and presents a large passband relative to that of an open circuit doublet. If W = the doublet width, 2h its length and H the distance from a reflector than for 2h lambda omicron/2 (lambda omicron = wavelength of the centre frequency), then 10/(kh)2 is approx. equal to (lambda omicron/2h)2.