Abstract: A method for controlling an antenna array includes determining, based on a beamstate, an initial weight vector of excitations. The initial weight vector is transformed into an active-impedance vector. When the modulus of any element of the active-impedance vector exceeds a threshold, the initial weight vector is unsafe. In this case, a substitute weight vector is identified such that (i) the initial and substitute weight vectors have a similarity measure that exceeds a similarity threshold and (ii) the substitute weight vector is safe. The antenna array may then be driven according to the substitute weight vector to emit radiation having a radiation pattern that approximates that of the beamstate. The substitute weight vector may be found by searching a library of safe weight vectors or by adjusting the excitations of the initial weight vector until a safe alternative is found.

Abstract: An antenna element is provided that is adapted to provide a more consistent horizontally polarized signal. In one embodiment, a radiator and counterpoise are provided with the counterpoise being disposed between the radiator and a ground plane in use. The feed location for feeding the radiator and the counterpoise is significantly spaced from the ground plane in use and the radiator and counterpoise diverge relative to this feed location.

Abstract: The invention is directed to an antenna structure for producing a horizontally polarized beam. In one embodiment, the antenna structure includes a first quarter-wave patch antenna and a second quarter-wave patch antenna that are positioned such that the ground planes of the patch antennas or a ground plane shared by the patch antennas is disposed between the patches of the two antennas and the shorting structures associated with the antennas are substantially aligned. In operation, the antenna structure is capable of processing an omni-directional, horizontally polarized beam.