Sumitomo Electric Designs Compact GaN HEMT Doherty Amplifier Using NI AWR Software
Sumitomo Electric Industries, headquartered in Osaka, Japan, operates in five business fields: automotive, information and communications, electronics, environment and energy, and industrial materials, and is developing life sciences and materials and resources businesses. The company focuses on developing new products and is the leading manufacturer of composite semiconductors in gallium arsenide (GaAs), gallium nitride (GaN), and indium phosphide (InP), which are widely used in semiconductor lasers, LEDs, and mobile telecommunications devices.
Next-generation 4G/5G telecommunication systems require power amplifiers (PAs) to operate with high efficiency over a wide frequency range in order to provide multiband and multi-standard concurrent operation. In these systems with increased bandwidth and high data rates, the transmitting signal is characterized by high peak-to-average power ratio (PAPR) due to wide and rapid variations of the instantaneous transmitting power. Therefore, it is important to provide high efficiency at maximum output power and at lower power levels over a wide frequency bandwidth. Sumitomo designers were tasked with developing an innovative high-power, wideband Doherty amplifier covering nearly 1 GHz of operation bandwidth at 2.25 GHz. The compactness of the design was of critical importance. In addition, low impedance levels from the transistor die to the packaged device gate terminal were required for circuit matching.
The designers chose the NI AWR Design Environment platform, specifically Microwave Office circuit design software and AXIEM planar electromagnetic (EM) simulator, for this PA design, because of the software’s high rate of first-pass design success. The fast and accurate AXIEM EM analysis helped overcome the challenge of using different high dielectric materials. The device achieved average efficiencies of 50-60 percent for output powers up to 100 W and significantly reduced the cost, size, and power consumption of the transmitters.
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