A multimode antenna having equalE- andH-planes

An antenna is described which utilizes two propagating modes in a circular waveguide. These modes are the
TM_{11}
and
TE_{11}
, which are complementary. The phase and amplitude is adjusted at the aperture so that both modes are in phase and of equal amplitudes. The resulting pattern is circularly symmetric having equal
E
- and
H
-patterns with extremely low back radiation.