Paul Eliot Green, Jr. (born January 14, 1924 in Chapel Hill, North Carolina) is an American electrical engineer who researched spread spectrum and radar technology. He was the son of playwright Paul Green.
Green majored in physics at the University of North Carolina. He also served in the Naval ROTC and continued in the Navy Reserve for many years, eventually retiring as a lieutenant commander. He received a master's degree in electrical engineering from North Carolina State University in 1948. His masters studies focused on cryptographic research, and were followed by Ph.D. from M.I.T. (1953) on a thesis on spread spectrum, supervised by Wilbur Davenport, Robert Fano and Jerome Wiesner. This involved co-creating the Rake receiver (with Robert Price) and supervision of its deployment in a first-ever spread-spectrum system, the Lincoln F9C (1950).
Following his studies, Green and Price (at Lincoln Laboratories), attempting to bounce radar waves off the planet Venus (1958). With Gordon Pettengill, he worked out a theory of range-Doppler mapping that was used on the Magellan probe mapping of Venus' surface twenty years later. He also designed the LASA (Large Aperture Seismic Array) for earthquake prediction, first deployed in Montana and Norway (at NORSAR) in 1963.