Optimizing CMOS LNA circuits through multi-objective meta heuristics

Particle swarm optimization (PSO) has shown to be an efficient, robust and simple optimization algorithm. Recently, the mono-objective version of the PSO algorithm was adapted and used to optimize only one performance of RF circuits, mainly the voltage gain of low noise amplifiers. In this work, we propose to optimize more than one performance function of LNAs while satisfying imposed and inherent constraints. We deal with generating the Pareto front linking two conflicting performances of a LNA, namely the voltage gain and the noise figure. The adopted idea consists of using the symbolic expressions of the scattering parameters ((S21) for the voltage gain, and (S11, S22) for input and output matching). For this purpose we use a Multi-Objective Optimization algorithm PSO incorporating the mechanism of the crowding distance technique (MOPSO-CD). Comparisons with results obtained using NSGA II are presented and ADS simulations, using 0.35µm CMOS technology, are given to show good reached results.