Millimeter-wave phase conjugation using artificial nonlinear surfaces

An artificial nonlinear surface has been developed using antenna-coupled mixers with optical interconnects for microwave and millimeter-wave phase conjugation. Prototype one-dimensional arrays have been constructed and have been used to demonstrate two-dimensional free-space phase conjugation at 10.24 GHz. The phase conjugation properties have been observed and verified by directly measuring the electric-field distribution of the conjugate wave under various conditions. Furthermore, the experiments have shown amplified conjugate wave power up to ten times of that of the incoming wave. This amplifying ability demonstrates the potential of such surfaces to be used in novel communications applications. (C) 1998 American Institute of Physics.