Question: In which area did this French engineer and physicist, whose name became synonymous to one of a series of concentric prolate ellipsoidal regions of space between and around a transmitting antenna and a receiving antenna system, contribute significantly?
Sentence (from "Periscope antenna"): In telecommunication, a periscope antenna is an antenna configuration in which the transmitting antenna is oriented to produce a vertical radiation pattern, and a flat or off-axis parabolic reflector, mounted above the transmitting antenna, is used to direct the beam in a horizontal path toward the receiving antenna.
Relevant evidence: No