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A wideband low-noise amplifier (LNA) based on the current-reused cascade configuration is proposed. The wideband input-impedance matching was achieved by taking advantage of the resistive shunt-shunt feedback in conjunction with a parallel LC load to make the input network equivalent to two parallel RLC-branches, i.e., a second-order wideband bandpass filter. Besides, both the inductive series- and shunt-peaking techniques are used for bandwidth extension. Theoretical analysis shows that both the frequency response of input matching and noise figure (NF) can be described by second-order functions with quality factors as parameters. The CMOS ultra-wideband LNA dissipates 10.34-mW power and achieves S 11 below -8.6 dB, S 22 below -10 dB, S 12 below -26 dB, flat S 21 of 12.26 ?? 0.63 dB, and flat NF of 4.24 ?? 0.5 dB over the 3.1-10.6-GHz band of interest. Besides, good phase linearity property (group-delay variation is only ??22 ps across the whole band) is also achieved. The analytical, simulated, and measured results agree well with one another.
Microwave Theory and Techniques, IEEE Transactions on (Volume:58 , Issue: 2 )
Date of Publication: Feb. 2010