9 Jul 01 16:47
Does anyone know of any prior art on this concept ?
The Whirligig - an End Fire Array of Two Turnstiles
The turnstiles are the usual crossed dipoles fed to produce CP. The End Fire Array is the usual one quarter wavelength spacing and 90 degree phasing to produce a uni-directional pattern. The combination of these two concepts will produce the Whirligig - an antenna that (aimed horizontally) would look a bit like a small Quad Antenna support structure less the wires.
It would be advantageous to orient it as an X rather than a cross. Less height, more symmetry and better circularity.
Obviously the relative phases could be fiddled to send RHCP or LHCP either forward or backward.
The application (for those that are curious) is UHF SatCom on aircraft where it is easy to provide coverage up, left and right; but difficult to provide coverage front and rear. With this Whirligig Antenna, the front and rear could be filled in quite easily to provide complete coverage for highly mobile platforms.
I haven't found any references to prior art, but I would not be surprized that someone out there somewhere has mentioned this concept before.
Email your comments or pointers to VE1BLL@rac.ca