Noise figure optimization of wide-band inductively-degenerated CMOS LNAs

This paper presents the design and measurement results of a wide-band inductively-degenerated 0.18-mum CMOS LNA targeted for the square kilometer array (SKA) radio telescope. A noise figure optimization procedure is discussed that allows selection of an optimum power consumption resulting in the lowest noise figure given the required bandwidth. The noise optimization procedure accounts for the parasitic resistances of both the transistor´s gate fingers and the gate inductor. Measured results of a single-stage 700 MHz-1400 MHz LNA are discussed. The LNA, designed in 0.18-mum CMOS, achieves noise figures better than 0.57 dB, gain (S₂₁) of at least 15 dB, input return loss of greater than 16 dB, output P1dB of 6 dBm, and output IP3 of 14.5 dBm while consuming 50 mW of power from a 1.5-V supply.