3.5 Ghz Triple Cascaded Current-Reuse Low Noise Amplifier

A triple cascaded current-reuse CMOS low noise amplifier (LNA) for 3.5 GHz WiMAX application is presented. Three common-source amplifiers are stacked and reuse the same current. This triple cascaded topology is able to enhance power gain but needs two coupling networks which costs enormous chip size. In order to have reasonable chip size, two coupling methods are investigated. To achieve input and noise matching simultaneously, an additional capacitor is employed to adjust quality factor and reduce the gate induced current noise. The measurement results show a maximum power gain of 21.7 dB and minimum noise figure of 3.11 dB. The power consumption is 5.16 mW. The chip including pads occupies 1.05 mm x 0.93 mm. A figure-of-merit of 49.7 is reached.