Patent ID: 8497808

Claim:
An omnidirectional antenna comprising: a plurality of traveling-wave (TW) structures comprising at least one ultra-wideband low-profile two-dimensional (2-D) surface-mode TW structure, the plurality of TW structures being adjacent to each other, and wherein the surface-mode TW structure is excited in mode-0 and comprises a 2-D surface-mode TW radiator for omnidirectional radiation, the 2-D surface-mode TW structures being further configured to have a diameter less than λ L /2 and a thickness less than λ L /10, where λ L is the free-space wavelength at the lowest frequency of operation of the 2-D surface-mode TW structures; a frequency-selective coupler placed in between adjacent TW structures; a feed network, wherein the feed network excites the plurality of TW structures in mode-0; and a conducting ground surface, wherein the conducting ground surface is of a canonical shape, the conducting ground surface further being positioned at a bottom side of the antenna, and having a surface area covering at least the projection of the antenna.