A 2-D Van Atta Array Using Star-Shaped Antenna Elements

A new passive 2-D Van Atta array is introduced with star-shaped antenna elements. The star-shaped antenna is proposed for low mutual coupling in the array. A single antenna element designed at 5.8 GHz has two orthogonal feeding ports with 23 dB port return loss and 28 dB isolation between ports. The mutual coupling among the antenna elements is less than -15.5 dB, which is 5 dB better than the conventional square patch antenna. Experimental results show that this array keeps a constant retrodirective characteristic at arbitrary injection polarization and direction. A stable bistatic radar cross section (BRCS) within 120deg angle can be achieved at 5.8 GHz