A 24-GHz Butler-Matrix-Based Switched Beamformer in GaAs

A 24-GHz switched beamformer in GaAs for a 4-element linear antenna array is proposed, which is composed of an absorptive SP4T switch and a 4×4 Butler matrix. Through the utilization of slow-wave microstrip lines and bridged-T coils, a compact chip size of 2 mm × 2 mm is achieved. The measured insertion loss at 24 GHz is within 11.16±0.95 dB and the measured phase error is less than 6° for the four beam states.