A Capacitor Assisting Triple-Winding Transformer Low-Noise Amplifier with 0.8-1.5dB NF $6-12\text{GHz BW} \pm 0.75\text{dB}$ Ripple in 130nm SOI CMOS

This paper presents a novel capacitor assisting triple-winding transformer (CTTF) low noise amplifier (LNA) with ultra-low noise figure (NF) and a flat passband gain in 130nm SOI CMOS process. The assisting capacitor in the triple-winding transformer expands the design space by enabling independent control of the coupling strength between each two inductors. The negative resistor enhanced by the assisting capacitor boosts the transformer gain that not only suppresses the noise from the second stage, but also leads to a wider passband by compensating the gain droop from the active transistors. Through two-stage simultaneous noise and power matching, the LNA provides a remarkable 0.8-1.5 dB NF, <−14dB S11, <−8dB S22, −11.8dBm IP1dB and 21.8-23.3dB power gain across the 6-12GHz passband with ±0.75dB ripple while drawing 20mA from a 3.3V supply. It reports the lowest NF so far.