A 8-12 GHz power amplifier with high out-of-band rejection

This paper proposes an 8-12 GHz monolithic power amplifier (PA) with high out -of -band rejection. This PA adopts an impedance conversion technique to reduce the Q of the output impedance of the amplifiers for all stages, which is used to achieve broadband matching performance. In addition, the bandpass matching structures and a trap circuit are adopted to effectively suppress out -of -band signals. The proposed PA is fabricated by using a 0.5 mu m GaAs pHEMT process. The measurement results show that the PA has an in -band small signal gain of 23 dB +/- 0.7 dB, input and output return loss are both better than -14dB, the saturation output power is about 23dBm, the power -added efficiency (PAE) is better than 20 %, and rejection ratios are 65dBc and 51dBc at 3 GHz and 17 GHz respectively. The area is of 2.3mm x 1.1 mm.