Dual Input Characterization of an Asymmetric Orthogonal Load Modulated Balanced Amplifier for Enhanced Linear Performance

This paper describes the characterisation of an asymmetric Orthogonal Load Modulated Balanced Amplifier (OLMBA) in Doherty-like operation. The OLMBA was characterized in both CW using a single input and with modulated signals as a dual-input device. The simulations demonstrated that good efficiency could be achieved up to 10 dB Output Back-Off (OBO). However, the single-input CW measurements showed some significant performance degradation. The device still maintained an efficiency of 35-57 \% over an OBO range of 6 to 10 dB. The device was then tested with a modulated signal in a dual-input configuration that gives more flexibility and might overcome some of the discrepancies observed in the single-input configuration. After linearisation, the device showed insensitivity to the crest factor applied (from 6 to 10 dB), maintaining the efficiency around 30\%, meaning that the asymmetric architecture worked well in expanding the OBO of the Doherty-like OLMBA.