Mm-wave CMOS circuits are expected to enter the consumer market in the next few years and become a part of most mobile devices offering a drastic increase in the data transfer speed compared to the available systems today. mm-wave car radars is also expected to become ubiquitous and increase the safety of the roads. High performance silicon technology will also find several applications in medicine once it can efficiently operate in the THz frequencies.

This dissertation follows two basic goals. On one hand, the goal is optimizing the performance of CMOS for the mm-wave technology. To reach this goal, mm-wave systems have been considered from device and circuit angles. From the device point of view, a systematic way of making high performance active devices have been proposed and various device parameters such as power gain, noise performance, power efficiency and stability have been analyzed and optimized. An extensive investigation of accurate modeling methods for transistors up and beyond 100 GHz has also been performed. On the circuit side, several high performance, low power 60 GHz low noise amplifiers and a power amplifier were designed and implemented. To increase the performance of such circuits, some novel techniques such as unilateralization have been proposed and implemented.

The other goal of this research was to investigate the true limits of CMOS technology. More specially, it has tried to answer this question that at any given technology node, what would be the ultimate frequency that one can design active circuits with acceptable performance and a reasonable power dissipation. To this end, some techniques to maximize the fmax of a CMOS transistor were proposed and few circuits, an amplifier and an oscillator were designed and implemented using these devices to operate beyond the ft of the technology.