Abstract: Systems and methods for optically aligning a transmitted beam with a received beam are provided herein. In some examples, a received beam is divided into a plurality of receive beamlets. The plurality of receive beamlets are coherently combined into a first optical beam. A second optical beam is coherently divided into a plurality of transmit beamlets forming a transmitted beam. The plurality of receive beamlets are used to determine a direction of the received beam. Phases of the receive beamlets are adaptively adjusted to maximize intensity of the first optical beam. Phases of the transmit beamlets are adaptively adjusted to steer the transmitted beam in a direction opposite to the direction of the received beam.

Abstract: A broadband composite dipole array (CDA) includes an array of macro dipoles on a non-conducting substrate adapted to receive radiation at two frequencies. Each macro dipole is an array of micro dipoles adapted to receive radiation at substantially the mean of the two frequencies. The micro-dipoles are coupled to each other by a parallel resonant circuit including a nonlinear element, wherein the minimum impedance of the circuit is a substantially short circuit at the difference frequency f1?f2, and the circuit has a substantially open circuit impedance in the range of frequencies from f1 to f2. The micro dipoles resonate efficiently at both frequencies f1 and f2 with low-loss. The nonlinear element in the resonant circuit generates a signal at the difference frequency which is the resonant frequency of the macro dipole antenna.

Abstract: A broadband composite dipole array (CDA) includes an array of macro dipoles on a non-conducting substrate adapted to receive radiation at two frequencies. Each macro dipole is an array of micro dipoles adapted to receive radiation at substantially the mean of the two frequencies. The micro-dipoles are coupled to each other by a parallel resonant circuit including a nonlinear element, wherein the minimum impedance of the circuit is a substantially short circuit at the difference frequency f1-f2, and the circuit has a substantially open circuit impedance in the range of frequencies from f1 to f2. The micro dipoles resonate efficiently at both frequencies f1 and f2 with low-loss. The nonlinear element in the resonant circuit generates a signal at the difference frequency which is the resonant frequency of the macro dipole antenna.