Design and Implementation of a High-Efficiency 45 W Compact Class-J Power Amplifier Based on a Simplified Real Frequency Technique for n77 5G New Radio Applications

In this paper, the design and methodology for the fifth-generation (5G) new radio (NR) 45 W class J power amplifier in gallium nitride (GaN) technology is presented. For compact output matching, a new concept using the drain capacitance of a power amplifier to satisfy the second harmonic termination of class J has been proposed. A high-efficiency and broadband 45 W power amplifier and 6 W driver are designed and implemented using mixed lumped element simplified real frequency technique (SRFT) by adjusting only the fundamental load. Stability analysis has been done using the loop gain method. Experimental results show that the implemented power amplifier demonstrates 46.5–47.3 dBm output power, 62–66.2% efficiency, and 9.9–11.9 dB gain with an outstanding compact size of 4.4 × 2.2 cm2 over the entire n77 fifth-generation band.