A patch antenna comprising: a ground plane; a patch radiator in a substantially parallel relationship to the ground plane, the patch radiator being substantially planar having a substantially square outline, and the patch radiator providing a resonant piece of microstrip transmission line capable of radiating from each edge of the patch radiator, each side of the square outline of the patch radiator being approximately half a wavelength in length at an operating frequency suitable for operation of the patch antenna; at least a first connection point for at least a first radio frequency signal; and at least a first feed structure arranged to connect the first connection point to at least two feed points on the patch radiator a first of said feed points being disposed adjacent to a first edge of the patch radiator, and a second of said feed points being disposed adjacent to a second edge of the patch radiator, the first and second edges being on opposed sides of a central region of the patch radiator, and the path length from the first connection point to the second of said feed points being longer than the path length from the connection point to the first of said feed points, wherein the first feed structure comprises at least a first transmission line arranged to connect the first of said feed points to the second of said feed points, the first transmission line having a first impedance and being disposed between the patch radiator and the ground plane in a substantially parallel relationship to the patch radiator and having a first spacing from the patch radiator, wherein the first spacing between the first transmission line and the patch radiator is set to a predetermined value based on a desired input impedance of the patch antenna. a ground plane; a patch radiator in a substantially parallel relationship to the ground plane, the patch radiator being substantially planar having a substantially square outline, and the patch radiator providing a resonant piece of microstrip transmission line capable of radiating from each edge of the patch radiator, each side of the square outline of the patch radiator being approximately half a wavelength in length at an operating frequency suitable for operation of the patch antenna; at least a first connection point for at least a first radio frequency signal; and at least a first feed structure arranged to connect the first connection point to at least two feed points on the patch radiator a first of said feed points being disposed adjacent to a first edge of the patch radiator, and a second of said feed points being disposed adjacent to a second edge of the patch radiator, the first and second edges being on opposed sides of a central region of the patch radiator, and the path length from the first connection point to the second of said feed points being longer than the path length from the connection point to the first of said feed points, wherein the first feed structure comprises at least a first transmission line arranged to connect the first of said feed points to the second of said feed points, the first transmission line having a first impedance and being disposed between the patch radiator and the ground plane in a substantially parallel relationship to the patch radiator and having a first spacing from the patch radiator, wherein the first spacing between the first transmission line and the patch radiator is set to a predetermined value based on a desired input impedance of the patch antenna.