Ultra-Wideband GaN Doherty PA for Next Gen Wireless Base Stations

Mitsubishi has developed an ultra-wideband gallium nitride (GaN) Doherty power amplifier for next generation base stations that operate from 3 to 3.6 GHz (600 MHz Bandwidth). The technology is expected to help reduce the size and energy consumption of next generation wireless base stations. Technical details will be presented at the IEEE Topical Conference on RF/Microwave Power Amplifiers for Wireless and Radio Applications (PAWR2017) during the Radio & Wireless Week (RWW) in the U.S. city of Phoenix, Arizona from January 15-18, 2017.

To help meet a rapid rise in demand for increasing wireless capacity, mobile technologies are shifting to next generation systems that raise capacity by allocating new frequency bands above 3 GHz and using multiple frequency bands. Generally, power amplifiers operate with less efficiency at higher frequencies. Also, different power amplifiers are needed for different frequency bands, which can require larger base stations. As such, extra-efficient power amplifiers compatible with multiple frequencies are in demand.

This new ultra-wideband GaN Doherty power amplifier from Mitsubishi Electric uses advanced frequency-compensation circuits with Doherty architecture for enhanced efficiency in a very wide band range.

The new power amplifier’s frequency-compensation circuit enhances efficiency over a wide frequency range to enable wider performance by three times, a world record for Doherty power amplifiers (with a 600 MHz bandwidth). Wideband, high-efficiency performance for efficient amplification of multiple radio frequencies by just one power amplifier will help to reduce base station size and cooling needs. Mitsubishi Electric’s high-efficiency GaN devices (MGFS39G38L2) have an efficiency of more than 45.9% in the 3.0 to 3.6 GHz frequency range, thereby reducing energy consumption. Further, an adjacent channel leakage ratio (ACLR) of -50 dBc is achieved with a commercial digital pre-distortion (DPD) technique for LTE (Long-Term Evolution) 20 MHz signals.