Design of High-Gain Sub-THz Regenerative Amplifiers Based on Double-italicG/italicsubmax/sub Gain Boosting Technique

摘要

This article reports the concept of a double maximum achievable gain (double-inline-formula tex-math notation="LaTeX"$G_{mathrm{ max}}$ /tex-math/inline-formula) core for the implementation of sub-terahertz high-gain amplifier design. The double-inline-formula tex-math notation="LaTeX"$G_{mathrm{ max}}$ /tex-math/inline-formula core is a inline-formula tex-math notation="LaTeX"$G_{mathrm{ max}}$ /tex-math/inline-formula core that adopts another linear, lossless, and reciprocal network that satisfies the inline-formula tex-math notation="LaTeX"$G_{mathrm{ max}}$ /tex-math/inline-formula condition onto an even number of cascaded transistor-level inline-formula tex-math notation="LaTeX"$G_{mathrm{ max}}$ /tex-math/inline-formula cores. It is shown that the double-inline-formula tex-math notation="LaTeX"$G_{mathrm{ max}}$ /tex-math/inline-formula core, due to its regenerative nature, can achieve much higher gain per stage than that of the same number of cascaded inline-formula tex-math notation="LaTeX"$G_{mathrm{ max}}$ /tex-math/inline-formula cores while satisfying the unconditional stability. Implemented in a 65-nm CMOS process, by adopting the proposed double-inline-formula tex-math notation="LaTeX"$G_{mathrm{ max}}$ /tex-math/inline-formula core, 247- and 272-GHz two-stage amplifiers achieve the peak gain of 18 and 15 dB, the gain per stage of 9 and 7.5 dB, and the PAE of 4.44% and 2.37%, respectively, while dissipating 21.5 mW.