IMS2011, TOKYO, JAPAN: Mitsubishi Electric Corp. announced that it has developed a gallium nitride high-electron mobility transistor (GaN HEMT) power amplifier for C-band satellites featuring the world's highest power-added efficiency (PAE) rating, 67 percent, an increase of more than seven points compared to conventional amplifiers.
The amplifier is expected to lead to smaller and lighter transmitter devices to help microwave communication satellites save power. Mitsubishi Electric will present its breakthrough at the International Microwave Symposium for 2011 (IMS 2011) at the Baltimore Convention Center in the U.S. city of Baltimore, Maryland from June 5–10.
The new amplifier's record of 67 percent PAE, more than seven points higher than conventional amplifiers, is enabled by the world's first harmonic tuning circuit placed in front of each GaN HEMT cell on the substrate.
The PAE was improved by second harmonic impedance of GaN HEMT with highly accurate input control. The harmonic tuning circuit comprises a MIM capacitor and a spiral inductor.
It has a high output power of 107W (50.3dBm). The unit is small and lightweight, measuring 17.4 x 24.0 x 4.3 mm and weighing 7.1g. It also features an internally impedance-matched GaN HEMT amplifier.
As more satellites complete their operational lifespan, the demand is increasing for new microwave communication satellites with smaller, lighter and more efficient satellite transponders. Conventional transponder devices use traveling wave tube amplifiers (TWTAs) because solid-state power amplifiers with GaAs HEMTs, which lack sufficient output power and efficiency, require an additional amplifier to gain high output power. More efficient GaN HEMT amplifiers with high output power, high-field electron velocity and high-breakdown fields are expected to replace TWTAs in communication satellites.
Going forward, Mitsubishi Electric intends to further enhance the efficiency and power performance of GaN HEMT amplifiers for satellites and wireless communication systems.