In this paper, an analytical tool of uniform 3D gainspace approach is proposed to analyze the impact of the lossy, linear and reciprocal embedding networks, as well as the lossy matching networks for near-fmax embedded amplifiers. Based on the uniform gain space approach, a super-gain-boosting technique, which involves the employment of the cross conductance to the differential pair as well as Y/Z-embedding networks is thoroughly proposed to significantly boost the power gain. Compared to the conventional gain boosting techniques, the proposed can significantly boost the Mason's U of a transistor, but also further obtain gain improvement benefiting from the intuitive uniform 3D gain-space approach. Finally, to validate the proposed analytical approach, a three-stage amplifier is implemented in a 65nm CMOS process based on the proposed super gain-boosting technique and over-push gain-boosting technique. The three-stage amplifier demonstrates a measured Psat of-1.95dBm and a maximum PAE of 2.87% at 189GHz, along with a maximum power gain of 32.1dB.

In this letter, we introduce a 194 GHz threestage differential driver amplifier operating at near-fmax frequencies. To address practical considerations associated with implementing on-chip embedding elements within the sub-THz frequency range, we employ a three-element embedded core consisting of three types of embedding networks. This design approach offers greater flexibility in selecting the required embedding elements. Based on the proposed embedded core, a three-stage drive amplifier is implemented in 65 nm CMOS process. The measurement results indicate that the proposed amplifier exhibits a smallsignal gain of 20.4 dB, a Psat of-2.1 dBm, and a peak PAE of 2.2% at 194 GHz.