ARLA/CLUSTER: High-Efficiency RF Power Amplifier

[João Gonçalves Costa]

NASA Marshall Space Flight Center developed this technology to reduce the power consumed by S-band microwave power amplifiers, which typically are the largest consumers of the limited power available aboard NASA spacecraft.

 Prior S-band microwave amplifier biasing arrangements, such as Class-A, -B, and -C, have typical conversion efficiencies of between 10% and 20%. 

These efficiencies are much lower than those obtained with Class-D power amplifiers in the VLF-HF band (85% to 90%). 

MSFC sought to apply the lower frequency Class-D methodologies to power amplifiers that would operate at the higher S-band frequency. In addition to extending some of the Class-D methodologies used in the VLF-HF regime to S-band frequencies, researchers also incorporated new techniques.

 The results were Class-D power amplifiers with a 49.7% DC-to-RF conversion efficiency at 2 to 3 GHz¿ a significantly higher efficiency than with prior S-band microwave power amplifiers.

 This higher efficiency translates into a five-fold increase in battery life for cellular telephones, trunked communication systems, and other devices. 

In addition, because it is made with commercial off-the-shelf components, this invention is lower in cost than other amplifier designs. 

It also generates less heat than other amplifiers, is more reliable, and is less prone to parasitic oscillation.

 These advantages are of great value to many applications where efficiency is critical, such as satellites, cellular phones, and other portable electronics.

(vide em: http://www.nttc.edu/technologies/technology.asp?technology_id=189 )