A Dual-Band Current-Reused LNA with the Switching of LC-Resonances

In this paper, a dual-band current-reused low noise amplifier with the band-switching of LC-resonances is designed and measured. Cascading series and parallel LC resonant networks are used to arrive at the matching of reflection coefficient at the input and output terminals. An inter-stage band-switching LC resonant network is used to suppress the signal leakage through the path from the drain of input transistor to the source of cascoded transistor at the frequency bands around 2.3 GHz and 5.2 GHz. This will result in band-switching dual-band transfer characteristics. Simulated S11 and S22 are lower than -10 dB. Simulated maximum gains are 17 and 14.5 dB for the two frequency bands, respectively. The simulated noise figures are less than 3.5 dB at the two frequency bands. The power consumption is 8.1 mW. The measured low and high central frequencies are shifted to 2.9 GHz and 5.5 GHz, respectively.