A 4.8 mW, 4.4 dB NF, wideband LNA using positively coupled transformer for V-band applications

In this paper, a V-band ultra-low power Low Noise Amplifier (LNA) with enhanced bandwidth (BW) is presented. A positively coupled cascode transformer (PCCT), formed using cascode inductors at the emitter of the cascode transistors, is used to couple the signal between the first and second stage. Using an optimum coupling factor of 0.23 for the PCCT, a bandwidth improvement of 15 % was seen during simulation. The prototype was implemented using 0.13 μm SiGe BiCMOS technology. Measurements show a peak gain of 13.5 dB, BW > 8 GHz, Noise Figure (NF) of 4.4 dB and an input 1-dB compression point (P_in,1dB) of -19 dBm. The LNA occupies a core area of only 0.05 mm² and consumes 3.7 mA from a 1.3 V supply.