Abstract: A combined antenna system mounted in a nose randome of an aircraft for both radar and ESM signals. A flat plate waveguide antenna, a twist panel, a selective reflector, and a feed are aligned along a longitudinal axis in the randome. The polarized electromagnetic energy is twisted 45 degrees; and the selective reflector passes the twisted electromagnetic energy and reflects energy polarized in planes substantially different than the twisted plane.

Abstract: Loop radiating elements for microwave frequencies which result in balanced ower division at the feed points and equi-phase currents in the radiating segments are in the form of an Alford loop design having a "kink" in the stripline path on the side of a printed circuit board opposite the cross-over to restore equal path lengths on both sides of a central feed terminal. Alternatively, the radiating segments of a loop may be in the form of end-loaded bent dipoles which are dual-fed on diametrically opposite points of the loop with equi-phase and amplitude signal. The result is loop radiating elements which have an axial null with a symmetrical doughnut radiating pattern.