14 July 2020
Mitsubishi Electric develops GaN PA module for 5G base-stations
Tokyo-based Mitsubishi Electric Corp has developed new technology to realize a gallium nitride (GaN) power amplifier (PA) module for 5G base-stations that offers a combination of a compact footprint (6mm by 10mm) and extra-high-power efficiency exceeding 43% (at the 5G frequency range of 3.4-3.8GHz).
The module, which uses a minimum number of chips in the matching circuit to control high-quality signal output, is expected to help realize 5G base-stations that are widely deployable and highly power efficient. Technical details of the new module are being presented at the IEEE International Microwave Symposium (IMS 2020) in August.
High-density mounting technology to realize compact PA 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 extra small and extra power efficient. Mitsubishi Electric’s new technology eliminates the need for transmission lines in 5G power amplifiers.
The new amplifier module’s matching circuit is integrated with surface-mount devices (SMDs), such as capacitors and inductors. By introducing a highly accurate electro-magnetic 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 (6mm x 10mm rather than 60mm x 78mm).
Power efficiency reduces 5G base-station power consumption
Using SMDs for the matching circuit can not only reduce the amplifier’s size but also decrease power efficiency because SMDs tend to have high power loss. 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 record power efficiency of 43-48% in the 3.4-3.8GHz bands used for 5G communications (rather than the 39-43% of the conventional power amplifier module).