A low power dual-band variable gain low noise amplifier

A low power dual-band variable gain low noise amplifier (DB-VGLNA) with multiple tunable gain control terminals was designed and implemented. In the proposed DB-VGLNA, a serial-parallel resonant filter network was used to achieve dual-band input impedance matching. In order to enhance gain tunability, three gain-adjustment stages, i.e. cascode amplifier with active inductor as variable load, common-gate amplifier and source follower with variable current mirror were simultaneously employed to vary and control gain. The current-reuse in cascode amplifier and common-gate amplifier reduced power consumption. Based on TSMC 0.18μm BiCMOS technology, the DB-VGLNA was verified. The results show that the DB-VGLNA has tunable gain (S₂₁) ranges of 1~13.5 dB and 0~16.5 dB at respective frequencies of 2.4 GHz and 5.2 GHz by three gain-adjustment stages. The both input return loss (S₁₁) and output return loss (S₂₂) are less than -10 dB, the noise figure (NF) is below than 5 dB. With the supply voltage of 3.3 V, the static power consumption is less than 15 mW.