Microwave antenna having an array of radiating elements for circularly polarized signals

Claim 1

A flat microwave antenna comprising: (a) a circular array of printed circuit elements each including first and second orthogonal dipoles separated by a dielectric, linear arrangements of said elements being positioned along respective radial lines of the antenna such that shorter arrangements are interposed between longer arrangements as the radial lines diverge sufficiently to provide adequate space for the shorter arrangements, and such that the density of elements in any sector of the circular array decreases with distance from a center of the array; and (b) first and second printed circuit feedline networks electrically-connecting first and second supply terminals to the first and second dipoles of the elements, respectively, each of said networks extending inwardly from the array periphery between the elements and continuously branching out until one branch is provided for each element, the path length from any dipole along the connecting feedline network to the supply terminal for said dipole being substantially equal to that from any other dipole to its respective supply terminal.