Load-Modulation Technique for Next Generation Mobile

In this research, an asymmetrical load-modulation power amplifier is proposed and described. The designed amplifier uses two GaN HEMT transistors with 25W and 45W peak power. The designed amplifier is targeting the sub-6 GHz 5G spectrum with 200 MHz bandwidth at a center frequency of 3.4 GHz to achieve a 70 W peak power with peak efficiency at 8 dB back-off. The performance of the fabricated circuit was able to show good efficiency at the back-off region. In addition, the amplifier was tested using a continuous wave (CW) and an 8 dB peak-to-average power ratio (PAPR). The measurements results using CW reveal a power-added efficiency (PAE) of 45% at the back-off region and more than 60% achieved at the peak power. Whereas the measurements using the modulated signal achieved 42% at 40 dB average output power with a 31 dB adjacent channel power ratio. Good isolation between the amplifiers' input is needed to minimize the effect of the reflected waves on the load-modulation operation.