Abstract

This paper introduces an optical technique for generation of phased array antenna drive signals for single and continuous mode beam scanning and beam formation. An optical system using two acoustooptic devices, imaging optics, and an array of high-speed detectors is used to generate the correctly phased signals. The required phase change on each detector is brought about by a frequency change in the acoustoptic device drive signal, which in turn maps frequency changes to changes in angular deflections. This results in a spatial frequency change on the detector plane. The detector array samples the generated phase distribution to produce the driving currents for the antenna elements. The Doppler shift in the acoustooptic interaction in the Bragg cells is used to produce the high-frequency carrier signal for the rf antennas. The use of optics eliminates expensive and bulky microwave frequency mixers. This processor can be operated up to a 10-GHz radar carrier frequency and provides system advantages such as single-parameter scan control, multiple-beam scanning, graceful degradation of antenna beam pattern with component failure, small-system losses, low-power requirements, and small size. The processor can be built in either bulk or integrated forms.

© 1988 Optical Society of America