Design, Analysis and Measurement Results of a Fully-Integrated Low-power LNA Presenting Faults

Abstract

We present in this paper the analysis, design and measurement results of a low noise amplifier (LNA) operating in the ISM band at 2.45 GHz. The circuit topology adopted was based on a current reuse technique to minimize the power consumption. A prototype was fabricated in a 0.18-μm standard CMOS technology and the measured power consumption was 1.1 mW. The measured input reflection coefficient was below -10 dB and the reverse isolation was higher than 20 dB. The measured insertion gain and noise figure were 5.6 dB and 4.8 dB respectively, with divergences from the simulated values of 5 dB and 2 dB, respectively. To explain these discrepancies, we devised an analysis on the circuit, including sources of uncertainties. Moreover, we characterized a transistor included in the LNA die, that helped to explain part of the disagreements. After including the uncertainty sources, we wereaable to explain a deviation of 3.9 dB in the insertion gain with respect to the simulated result.