Performance Modeling and Shaping Function Extraction for Dual-input Load Modulated Power Amplifiers

This paper proposes the method of extracting a shaping function for operating a family of Dual Input Power Amplifiers operating with modulated signals such as OFDM-based 5G new radio (NR) signals. The shaping function describing the drive profile for each input was implemented using a look-up table (LUT) approach. This table can be constructed from the previously measured PA data to target various objectives, such as the linearity or efficiency. The paper focuses on performance modelling to have a smooth mathematical equation to predict performance. Based on the prediction, we can extract the shaping function targeting the maximization of linearity or efficiency. Experimental results were conducted with a 100 MHz bandwidth 5G NR signal with a 30 kHz subcarrier spacing. The linearize ability of different objectives is evaluated with digital predistortion.