A 4-9 GHz LNA With Out-of-Band Gain Rejection Method

This paper proposed a 4-9GHz Low noise amplifier (LNA) which is based on 0.25-μm GaAs pHEMT process. The proposed LNA adopts a method to achieve better out-of-band gain rejection performance. This method is realized by adjusting the reactance characteristic of the inductor used in the matching network. The post-layout simulation results show that the 3dB bandwidth is 2.9-10.6GHz. In the design band (4-9GHz), the gain is of 26.5±0.4 dB, the noise figure is of 0.91 ~ 1.22 dB, and the output P -1dB is of 13.7 ~ 17 dBm respectively. The proposed LNA has a compact chip size of only 1.44 mm ² , including all DC and RF pads.