An ultra wideband low-power low-noise amplifier using coupled inductors

This paper presents a low power wideband low noise amplifier (LNA) based on cascade current-reused topology using coupled inductor in a 0.18μm CMOS technology. Coupled inductors are used to provide feedback via mutual inductance in order to simultaneously achieve high gain and bandwidth (BW) at low power consumption. The main advantage of the proposed topology lies on the availability of a high degree of freedom on adjusting the gain, bandwidth, stability and input impedance matching. Design guidelines for improving the gain and bandwidth of the LNA at low power consumption are developed in the form of analytical expressions. The proposed circuit can achieve power gain of 14±.2dB and noise figure (NF) of 3.7±.5dB within the bandwidth of 3.1GHz-10.6GHz. The input and output return losses are lower than −10dB and −9dB across 3.1–10.6GHz respectively. Group delay variation is ±25ps across the whole band. Compared to some other LNAs which use current-reused cascade without inductive coupling reported before, the proposed circuit has lower power consumption and smaller inductor values. The circuit draws a total of 3.24mA from a 1.5V supply voltage.