Phased array antenna employing linear scan for wide-angle arc coverage with polarization matching

An antenna feed arrangement comprising:

• a plurality of feed elements arranged in an array and capable of launching or receiving a beam of electromagnetic energy polarized in a first direction, the array including a fixed linear phase taper along a first axis across the aperture of the array to cause the beam to be squinted at an angle 90 degrees-.alpha.;
• phase shifting means connected to the plurality of feed elements and capable of selectively producing a predetermined linear phase taper along a second axis across the aperture of the array for causing the squinted beam to traverse a predetermined arc in the far field of the antenna arrangement when scanned along the second axis of the array orthogonal to the first axis;
• polarization diplexing means capable of bidirectionally directing orthogonally polarized signals along one path in the far field of the antenna arrangement and along first and second separate paths in the near field of the antenna arrangement for interception along the first one of the paths by the array of feed elements;
• first polarization rotating means disposed between the diplexing means and the array with the surface normal vector of the polarization rotating means at an angle to a ray directed from the center of the aperture of the array to the center of the far field of view of the antenna arrangement which substantially corresponds to the angle of squint of the beam generated by the array, the polarization rotating means being capable of rotating a signal polarized in a first direction at the aperture of the array into a signal polarized in a second direction;
• and
• second polarization rotating means disposed between the diplexing means and the first polarization rotating means at a predetermined acute angle .gamma. to the first polarization rotating means, the second polarization rotating means being capable of rotating a signal polarized in the second direction from the first polarization rotating means into a signal polarized in the first direction which is matched to the polarization of the beam received from the diplexing means along the first separate path.