Series-fed beam-scanning antenna employing multi-stage configured microstrip antennas with tunable reactance devices

A series-fed beam-scanning array employing a MUlti-Stage Configured microstrip Antenna with Tunable reactance devices (MUSCAT) is proposed. The proposed antenna significantly expands the beam scanning range and achieves high efficiency. This antenna comprises unit element groups, whose elements are placed close to each other and employ tunable reactance devices. Analyses and experiments on the unit element groups show that their multi-stage configuration extends the phase shift range and increases the radiation efficiency, e.g., a 120° phase shift and the radiation efficiency of more than 50% are achieved, when three stages are employed. The radiation pattern of the fabricated MUSCAT array antenna comprising eight unit element groups is measured. A beam scanning range of 27°, which is greater than twice the beam scanning range of a non-multi-stage configuration, is achieved.