High Performance Three-Stage 30GHz CMOS Single-to-Differential LNA

A low-noise amplifier (LNA) integrated with active balun is presented. The proposed LNA has three stages. A common source (CS) first stage is coupled to a differential cascode stage by means of a common source (CS) - common gate (CG) active balun. The active balun is a high gain amplifier that converts the low noise output from the first stage into a differential mode signal. The third stage is a differential cascode amplifier that further enhances the gain and the reverse isolation. The circuit is designed and simulated using 0.18 mu m standard RF CMOS process using BSIM3 model with a center frequency of 30GHz. The simulated results show that the balun-LNA achieves a high gain (S21) of 44.57 dB with 2GHz bandwidth. The LNA has ultra-low noise figure (NF) of 0.95 dB and reverse isolation (S12) of -78.55 dB. The input return loss (S11) and output return loss (S22) are -19.81 dB and -26.42 dB respectively. The circuit draws 17.88 mA from 1.8 V supply voltage.