A 120–140-GHz LNA in 250-nm InP HBT

This letter presents a $D$ -band low-noise amplifier (LNA) in 250-nm InP HBT technology for the next-generation wireless applications. The LNA has a measured peak gain of 13 dB, a 3-dB bandwidth greater than 20 GHz (120–140 GHz), and a measured noise figure (NF) of less than 6 dB in the band. A reduction in the 3-dB bandwidth from simulation was observed during the measurements which was attributed to the substrate waves using full chip electromagnetic (EM) simulation. EM simulations show that a partial or complete removal of the back side metallization of the InP substrate, holes in metal-1 ground plane, or a strategic placement of through-substrate vias suppress these substrate waves. To the authors' knowledge, this is the first 120–140-GHz LNA in the InP 250-nm HBT technology.