A two-way power-combining amplifier operating from 112-142GHz is presented. Integrated in Infineon's 0.13µm SiGe-BiCMOS technology,it delivers 17dBm of peak saturated power to a 50O load at 13% PAE. Five fully-differential,transformer-coupled amplifier stages per path provide 34dB of forward transmission gain. Each 5-stage PA consists of capacitively gain-enhanced pre-drivers operated from 1.5V,followed by an inductively gain-enhanced cascoded driver powered by 3.3V. BJT models relevant at frequencies beyond 100GHz are evaluated to outline the trade-off between stability and gain exploited in this work. The design and layout of a folded,fully-differential,?/4 power combiner is also presented,along with a full two-port characterization of the power-amplifier prototype.