Mitsubishi Develops Small, Efficient GaN Power Amplifiers for 5G Base Stations

Mitsubishi Electric Corporation has developed a new technology to manufacture Gallium Nitride (GaN) power amplifier modules for 5G base-stations. The new GaN module offers a combination of a compact (6mm x 10mm) footprint and high power-efficiency (43% for the 5G frequency band from 3.4 - 3.8 GHz). It uses a minimum number of chip components for matching to control high-quality signal outputs, and is expected to help realize 5G base-stations that are widely deployable and highly power efficient. Technical details of the new module will be presented at the virtual IEEE International Microwave Symposium which will be held in August, 2020.

Key Features of the Power Amplifier:

  1. High-density mounting technology to realize compact (6 x10 mm) power amplifier module for more widely deployable 5G base-stations
    • In 4G base-stations, which do not use massive Multiple-Input and Multiple-Output (mMIMO) antennas, power amplifiers use metal-foil transmission lines for the matching circuit. While this lowers power loss, resulting in high-efficiency operation, transmission lines take up space and make it difficult to realize base stations that are both small and power efficient. Mitsubishi Electric's new technology eliminates the need for transmission lines in 5G power amplifiers.
    • The new amplifier module's matching circuit uses surface mount devices (SMDs), such as capacitors and inductors. By introducing a highly accurate electromagnetic field analysis method and applying a unique technology for the dense arrangement of SMDs, Mitsubishi Electric was able to reduce the amplifier's size to just one-ninetieth that of conventional power amplifiers.
  2. Ultra high power efficiency reduces 5G base-station's power consumption
    • High-efficiency GaN transistors help to increase the efficiency of the power amplifier.
    • Using SMDs for the matching circuit can reduce the amplifier's size but also can decrease power efficiency because SMDs tend to have high power losses. Mitsubishi Electric's new technology, however, creates a matching circuit using a small number of SMDs. Furthermore, the SMDs offer the same electrical characteristics as those of metal-foil transmission lines. The resulting power amplifier module achieves a world-leading power efficiency rating of more than 43% in the 3.4-3.8 GHz bands used for 5G communications.

5G base stations, which use mMIMO antennas to form multiple radio-frequency beams for simultaneous connection with other base-stations and massive users, coordinate radio-frequency component operation on the mMIMO antenna panel. Since the components are arranged densely on the panel, each one must be very small. The power amplifier, which consumes the most energy in the antenna, also must be very efficient to avoid problems with heat dissipation.