A Gain Cell With Unilateralization and Gain-Enhancement Techniques for High-Gain Distributed Amplifier

This article presents a novel circuit topology of gain cell for high-gain and broad-bandwidth distributed amplifier (DA). To enhance the gain with no deterioration in terms of bandwidth, no additional dc power dissipation and no increment of chip area, the unilateralization, interstage series-resonance, inductive-peaking, and current-reused techniques are incorporated dexterously into the proposed gain cell. The detailed analysis of gain enhancement and bandwidth improvement benefiting by the proposed gain cell is evaluated combined with simulation experiments. Experiments indicate that, by using the same process, the DA using the proposed gain cells achieves a gain improvement in excess of 8 dB larger than the DA using conventional gain cell without sacrificing the upper cutoff frequency, chip size, and dc power dissipation. Based on the theoretical analysis, a design methodology for high-gain DA is developed, and two single-stage DA prototypes, denoted by DA1 and DA2, are designed and implemented by using 0.25-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $ </tex-math></inline-formula>m GaAs pseudomorphic high electron-mobility transistor (pHEMT) process to contrastively verify the proposed techniques. The DA1, using the proposed gain cell without unilateralization technique, provides a high average gain up to 19 dB, 14-dBm OP<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{1\,{dB}}$ </tex-math></inline-formula>, and 2.5-dB typical noise figure across the frequency range from 2.8 to 24 GHz, while the DA2 features an average gain of 18.5 dB and 15-dBm OP<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{1\,{dB}}$ </tex-math></inline-formula> in the frequency range from 2.8 to 27.2 GHz with a chip area of 2.52 mm2.