A microwave radar antenna that substantially comprises molded or extruded thermoplastic components that are assembled into completed assemblies, are then metallized by either electroless copper or are electroplated with copper to achieve RF conductivity. The finished subassemblies are joined together forming the completed antenna. The molded, metallized, plastic antenna uses a thermoplastic material, such as polyetherimide, or suitable high strength, high temperature thermoplastic that is used to injection mold or extrude detailed microwave components. The molded components are assembled, using epoxy adhesives, solvents or other mechanical method into microwave subassemblies. These subassemblies are then either electroless copper plated or electroplated to provide RF conductivity. The metallized subassemblies are then joined together using mechanical methods to form a completed radar antenna, replacing heavier more costly metal radar antennas. Specifically, the molded, metallized, plastic antenna is comprised of an antenna aperture and electromechanical phase shifter section, centerfeeds comprising a horizontal feed network, interconnecting waveguides, a vertical feed network including conventional rotary field phase shifters, and a sum and difference monopulse feed network. The antenna also includes a suitable beam steering controller that provides electronic antenna beam steering and power supplies. The use of the present microwave antenna incorporating molded, metallized, plastic components results in an antenna having better performance, lighter weight, and much lower manufacturing costs than conventional metal antennas.