Patent ID: 6933907
Filing Date: 2005-08-23
Classification: H01Q

Abstract:
1. A variable directivity antenna comprising: at least two antenna elements each exhibiting a 8-shaped directivity pattern, said antenna elements being disposed generally in parallel with and spaced from each other by a distance shorter than a quarter of a wavelength employed; and combining means coupled to said at least two antenna elements via associated feeders having different lengths; the difference in length between said feeders being such that received signals resulting from reception by said at least two antenna elements of radio waves coming from a second direction opposite to a first direction toward and perpendicular to the length direction of said at least two antenna elements can be coupled in generally 180° out of phase to inputs of said combining means; said variable directivity antenna further comprising variable phase means disposed between one of said at least two antenna elements and said combining means, said variable phase means being adapted to selectively assume a first state in which said variable phase means couples said received signal from said one antenna element to said combining means without changing the phase of said signal, and a second state in which said variable phase means inverts the phase of said received signal from said one antenna element before coupling to said combining means.