Scanning cup-dipole antenna with fixed dipole and tilting cup

Abstract

Antenna apparatus having a fixed dipole and a rotating cup. The cup is formed from a cylindrical conductor shorted at its base to a conducting plate. The fixed dipole is recessed within the cup and has a coaxial transmission line feed that penetrates through a base plate of the cup and is coupled to the dipole. The present invention achieves beam scanning by mechanically rotating only the cup, and wherein the dipole and feed remain fixed. The antenna may further comprise a second fixed dipole oriented orthogonal to the fixed dipole. The dipole feed may be a hybrid coupler network coupled by way of a plurality of coaxial transmission line feeds and a four-post balun to the fixed dipoles. The first and second crossed dipoles lie in a plane that is generally orthogonal to a central axis of the antenna. In an alternative embodiment, the dipole feed may be a turnstile, crossed-dipole feed. In another embodiment, a transmission line feed is directly coupled to a crossed dipole having asymmetrical arms. The antenna may also embody an array of symmetrical dipoles. The dipoles of any of the disclosed antennas may be scaled for any frequency.