GaN Device for Highly Efficient Power Amplifiers

Fujitsu has been developing gallium nitride high electron mobility transistors (GaNHEMT) for small transmitter amplifiers for Long Term Evolution (LTE) base stations. The use of GaN-HEMT in highly efficient transmitter amplifiers has attracted much attention because of its high breakdown voltage characteristics. High-efficiency amplifiers with high gain are needed to decrease the power consumption and size of base stations. This paper describes the development of high-power GaN-HEMT operating at high voltage for LTE base stations. First, we introduce the advantages of GaN-HEMT in terms of its physical properties and GaN-based power amplifiers. Then, issues to be solved in the early developing stage of GaN-HEMT are focused on and the current status is described. Efficiency data of power amplifiers are shown. Finally, the future outlook is discussed in detail.