Patent ID: 8570239

Claim:
A substantially omni-directional antenna for wireless electromagnetic communications, the antenna comprising: an electrically conductive surface shaped to have a spiraling cross-section, the surface forming an internal cavity, the surface forming an internal channel to an external surface, the surface forming an internal wall common to the internal cavity and the internal channel, the internal wall having a longitudinal length and a longitudinal opening configured to allow radio frequency (RF) energy access to the internal channel and a width of the internal cavity being greater than a width of the internal channel such that in a plane perpendicular to the longitudinal length, the antenna is omni-directional with a maximum to minimum qain variation within a specified delta value and is polarized parallel to the plane; and an electrically conductive feed positioned to feed the antenna at the internal wall, the feed and the longitudinal opening being electrically coupled to induce an electric field along the longitudinal opening, the antenna being configured to transceive a wireless signal polarized parallel to the plane.