Miniaturized ultra-wideband multifunction antenna via multi-mode traveling-waves (TW)

A multifunction antenna comprising:

• a unidirectional radiator, a plurality of traveling-wave (TW) structures comprising stacked ultra wideband low-profile two-dimensional (2-D) surface-mode TW structures, wherein the surface-mode TW structure is excited in mode-0 and comprises a 2-D surface-mode TW radiator for omnidirectional radiation, a dual-mode feed network consisting of at least two separate feed networks, and a conducting ground plane;
• wherein the plurality of TW structures and feed networks being cascaded in a stack, with the appropriate frequency-selective coupler or decoupler between adjacent radiators;
• wherein the 2-D surface-mode TW structures being further configured to have a diameter less than λL/2and a thickness less than λL/10, where λL is the free-space wavelength at the lowest frequency of operation of the 2-D surface-mode TW structures;
• wherein the multi-mode feed network consisting of at least two separate feed networks, one for the unidirectional radiator and one for each mode-0 2-D TW structure;
• and
• 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.