A novel active variable gain X-band amplifier in SiGe technology

In this paper, a new structure based on variable gain amplifiers (VGAs) in SiGe technology with high linearity (Pin1dB > 8 dBm) and high dynamic range (> 30 dB) under 3.3 V is presented. In this proposed technique, two VGAs and a passive attenuator are used to improve the linearity especially at high attenuation. The simulated gain errors are less than +/− 0.1 dB for a 0.5 dB step over the whole dynamic gain range (31.5 dB). The Pin1dB is better than 8 dBm at the maximum gain of 8 dB and better than 22 dBm above 16 dB of attenuation.