Design of a tunable LNA and its variability analysis through surrogate modeling

In this paper, a tunable low noise amplifier (LNA), which provides a bandwidth of 1 GHz, has been designed. The tunability of the LNA has been achieved by employing MOS varactors in accumulation mode. A shift in the LNA performance has been observed with the change in the total capacitance of the varactors through the control voltage. Starting from 2 to 3 GHz, the proposed tunable LNA provides a noise figure (NF) of less than 3 dB, a voltage gain of 12 dB and higher, while maintaining input and output power matching (S₁₁ and S₂₂) metrics at least below −12 dB. The total power consumption of the circuit is 23 mW. Moreover, two case studies that demonstrate the usage of surrogate modeling in RF circuit design have been described. Three- and six-dimensional surrogate models have been built to illustrate the effect of bondwires on the variability of several LNA design metrics.