A 131–162-GHz Wideband CMOS LNA Using Asymmetric Frequency Responses of Triple-Coupled Transformers

Abstract

A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$D$ </tex-math></inline-formula> -band wideband low-noise amplifier (LNA) is presented, which consists of five-cascaded differential amplifiers fabricated in a 40-nm RF CMOS process. Each stage has a common gate (CG) configuration to have low noise at the high frequencies. Triple-coupled transformers are introduced in all stages to increase gains and to make interstage matchings, which have asymmetrical frequency responses. The input and output <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}$ </tex-math></inline-formula> factors of the transformers are tailored to achieve staggered matchings for wideband characteristics. This allows it to have a flat gain of 19.5–20.5 dB and a noise figure of 6.2–9.0 dB at 136–159 GHz. It shows a peak gain of 20.9 dB at 153 GHz and a noise figure of 6.2 dB at 148 GHz. It has a minimum <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\mathrm {IP}}_{\mathrm {1\,dB}}$ </tex-math></inline-formula> is −19.7 dBm, and occupies 0.24 mm2 including I/O pads with the core size of 0.09 mm2. It consumes a total dc power of 49 mW from a 1-V supply.