Updated January 15, 2019 to add Mitsubishi's response to Microwave Journal's question about the output power of the PA.

To support 5G, Mitsubishi Electric Corporation has developed a digitally controlled, high efficiency GaN power amplifier (PA) covering 1.4 to 4.8 GHz, enabling a single PA to cover multiple cellular bands.

The PA design uses two parallel GaN transistors with what Mitsubishi calls an “advanced load modulation circuit,” which expands the bandwidth and maintains high efficiency: above 40 percent over the 110 percent bandwidth.

Mitsubishi digitally controlled PA

In the company’s announcement, Mitsubishi did not disclose the output power of the amplifier. The release did specify the efficiency was achieved using a communications signal with a 6.5 dB peak-to-average power ratio (PAPR). Responding to Microwave Journal's question about the output power, a spokesperson emailed “The average output power of the amplifier is several watt class.”

The input signal to the PA is digitally controlled using Mitsubishi’s artificial intelligence (AI) technology, called Maisart (from “Mitsubishi Electric's AI creates the state-of-the- art in technology”). The AI apparently uses machine learning to optimize the input signal, reducing power consumption to achieve higher efficiency.

The company claims this is the first digitally controlled GaN amplifier.