This paper describes the design of a 5.7–6.4GHz Ga As Heterojunction bipolar transistor(HBT)power amplifier for broadband wireless application such as wireless metropolitan area networks.A bias circuit is proposed which enhances the power gain and provides a good linearity.Using the wideband matching network techniques with trap circuits embedded to filter the harmonics and the diode-based linearizing techniques,a broadband power amplifier module was obtained which exhibited a gain above 28d B.This is about 1d B improvement compared with those normal bias circuits at a supply voltage of 5V in the frequency range of 5.7–6.4GHz,measured with Continuous wave(CW)signals.The saturated output power was greater than 33d Bm in 5.7–6.4GHz and the output 1d B compression point was greater than 31d Bm.The phase deviation was less than 5 degrees when the output power below 33d Bm.The second and third order harmonic components were also less than-45d Bc and-50d Bc. This paper describes the design of a 5.7-6.4GHz Ga As Heterojunction bipolar transistor (HBT) power amplifier for broadband wireless application such as wireless metropolitan area networks. A bias circuit is proposed which enhances the power gain and provides a good linearity. Using the the wideband matching network techniques with trap circuits embedded to filter the harmonics and the diode-based linearizing techniques, a broadband power amplifier module was obtained which galvanized a gain above 28d B. This is about 1d B improvement compared with those normal bias circuits at a supply voltage of 5V in the frequency range of 5.7-6.4GHz, measured with Continuous Wave (CW) signals. The saturated output power was greater than 33d Bm in 5.7-6.4GHz and the output 1d B compression point was greater than 31d Bm. phase deviation was less than 5 degrees when the output power below 33d Bm. The second and third order harmonic components were also less than-45d Bc and-50d Bc.