Reconfigurable 2 × 2 multi-port amplifier using switching mode hybrid matrices

This letter presents a new 2 × 2 multi-port amplifier (MPA) structure using switching mode hybrid matrices (SMHM's) that can improve both system reliability and flexibility by controlling signal paths without complicated circuitry. Unlike previously reported MPA structures which have fixed input and output relations, the proposed MPA can select the number of PA's for signal amplification and produce flexible output patterns depending on the mode selection of the switches. For a 2 × 2 structure, the input signal can be amplified by a single PA or two PA's and then be delivered to any one of the two output ports. In addition, the amplified signal by a single PA or two PA's can also be delivered to both output ports with a 90° phase difference. To verify the proposed structure, a simplified MPA is tested at 900 MHz ISM band.