Abstract: A dual band, phased array antenna especially adaptable for tactical radar capable of performing search, track and identification in a hostile jamming environment. The dual band array antenna is essentially two antennas sharing a common antenna aperture. The two antennas possess separate feed system and beam steering control. Thus, the beams for each frequency band can be steered independently and simultaneously. This design utilizes an ultra-wide band radiating element which can operate over approximately an octave bandwidth encompassing two adjacent microwave bands. In particular, the dual band signals can be received efficiently by the radiating element. A dual band coaxial-to-waveguide transition can be used to carry the signals to a diplexer. The dual band signals are separated at the diplexer and can be processed in separate feed networks.