This article proposes a high-gain and low-power low-noise amplifier (LNA) by adopting a simultaneous noise- and input-matched (SNIM) maximum achievable gain (G(max)) core. The G(max)-core is implemented by adjusting the infinite combinations of embedding networks with three passive elements. Based on the proposed two-port noise analysis for implementing the G(max)-core, the input stage Gmax-core can achieve a simultaneous power gain and noise matching. The adoption of the G(max)-core in the input stage can maximize the amount of gain per stage, leading to higher total power gain and lower noise figure (NF). The two-stage 150-GHz LNA adopting the SNIM G(max)-core is implemented in a 65-nm CMOS process. The measurement results show a peak gain of 17.9 dB at 152.2 GHz, 3-dB bandwidth of 11 GHz, NF of 4.7 and 6.2 dB at 148 and 150 GHz, respectively, and a peak power added efficiency (PAE) of 7.7% while dissipating only 13.73 mW. This work shows the highest gain per stage and the lowest NF with the lowest dc power consumption among other reported CMOS D-band amplifiers.