rearward looking radar

For all you electronics/missel fans out there(who think no one could get within 10 miles of an F-22).In vietnam phantoms were getting splashed left and right by little mig-15s who snuck up behind them,forceing them criscross back and forth when traveling through hostile area.Since we havent had any major air wars since vietnam except for the arab/isreali and india/pakastan slugfests,I wonder if this would still be a problem today.I wonder if its ever been considered to carry a wing mounted rearward looking radar