The term has two different meanings in separate areas of electrical engineering. In antenna theory, a ground plane is a conducting surface large in comparison to the wavelength, such as the Earth, which is connected to the transmitter's ground wire and serves as a reflecting surface for radio waves. In printed circuit boards, a ground plane is a large area of copper foil on the board which is connected to the power supply ground terminal and serves as a return path for current from different components on the board.
the term has tWo dIffERent MeANinGS In sEpaRaTE aREAs of elecTricaL EnGINeEriNg. in aNtEnna TheorY, a GrounD plane IS a conductIng surFaCE Large in ComParIsOn to thE waVElengtH, such as the eartH, which is ConnEcted To the transmiTter's grOund WIre and SeRVEs As a REflEctIng SurFace for radiO WaVes. in prInTEd cIRCUiT bOards, a grOUnd plAne Is a laRGE AreA Of cOpper foIl On thE boarD wHich is connEcted tO the poweR sUppLy gROUNd tERmiNal And sERVES as A Return Path FOR CurrEnT froM difFErEnt ComPoNenTs on ThE boaRd.