A 67% PAE, 100 W GaN power amplifier with on-chip harmonic tuning circuits for C-band space applications

This paper describes a high efficiency and high output power GaN power amplifier for C-band space applications. The amplifier uses on-chip harmonic tuned FETs to improve dc-to-rf conversion efficiency. A 2^nd harmonic input tuning circuit is incorporated into each unit on-chip FET cell and realizes high precise control of 2^nd harmonic input impedance. In addition, 2^nd and 3^rd harmonic output impedances are optimized with external output matching circuits. A 100 W power amplifier with 4-chips achieves a 67.0% PAE (72.4% drain efficiency) at 3.7 GHz under CW operating conditions. To the best of our knowledge, this is the highest efficiency of C-band power amplifiers ever reported with over 100 W output power.