A microwave antenna assembly is printed on a substrate with a first face and an opposing second face. The assembly includes at least one antenna disposed on the front face of the substrate and a balun disposed on the rear face of the substrate. A first microstrip on the front face is coupled to the antenna(s). A second microstrip on the front face is coupled a feed line. A coplanar strip on the rear face is electrically coupled to the second microstrip and electromagnetically coupled to the first microstrip.