PERFORMANCE IMPROVEMENT OF POWER AMPLIFIERS USING AN ASYMMETRICAL SPURLINE STRUCTURE.

In this article, an asymmetrical spurline structure with dual rejection bands is proposed to reduce the higher harmonics of microwave power amplifiers. To evaluate the effect of an asymmetrical spurline structure on microwave amplifiers, two InGaP HBT power amplifiers were designed and fabricated. One of them has an asymmetrical spurline structure at the output section, while the other has a conventional 50Ω microstrip line only. The results show that the asymmetrical spurline structure suppresses the second and third harmonics by more than 27 dB at the output and yields an improved power added efficiency (PAE) and output power by 6 to 8 percent and 1 to 4 percent, respectively. [ABSTRACT FROM AUTHOR]