ACOUSTOOPTIC LIQUID-CRYSTAL ANALOG BEAM FORMER FOR PHASED-ARRAY ANTENNAS

A compact phased-array antenna acousto-optic beam former with element- level analog phase (0-2pi) and amplitude control using nematic-liquid- crystal display-type technology is experimentally demonstrated. Measur ements indicate >6-bit phase control and 52.6 dB of amplitude-attenuat ion control. High-quality error calibration and antenna sidelobe-level control is possible with this low-control-power analog beam former. O ptical system options using rf Bragg cells or wideband Bragg cells are discussed, with the rf design being the current preferred approach. T ransmit-receive beam forming based on frequency upconversion-downconve rsion by electronic mixing is introduced for the rf Bragg-cell beam fo rmer, and comparisons with digital beam forming are highlighted. A mil limeter-wave signal generation and control optical architecture is des cribed.