Improvement of polarization isolation in antennas

摘要

An antenna presenting improved polarization isolation is disclosed which presents at least two columns of rectangular micro-strip or patch elements which each has a single, linear polarization. Each column presents radiation elements of either about +45 or -45 degrees. At least two such columns are combined such that an antenna is obtained which then becomes dual polarized. Furthermore the columns are arranged such that the patches are alternately sidewise displaced to form a herringbone pattern. In other words a next patch of one column is placed on the symmetry lines through nearby patches of the other column. In this way the coupling between the patches is minimized and a high isolation is achieved between the two states of polarization. The achieved two linear states of polarization are utilized separately for polarization diversity. Furthermore in the preferred embodiment the structure of the antenna is designed to compensate for pointing errors between the columns due to unsymmetrical ground-planes.