| CMOS technology continues to expand its operating regime into higher frequency bands that used to require more exotic processes, and is now the dominant process for "conventional" radio-frequency circuits used in cellular phones and other applications in the low-GHz frequency range. As CMOS devices continue to scale below the 130-nm process node, the next target is the millimeter-wave regime with frequencies in the 10's of GHz. In this dissertation, we focus on millimeter-wave wireless transmitters, and in particular, how to efficiently generate and radiate power from CMOS chips at these high frequencies.;At millimeter-wave frequencies, resonant antennas become small enough to fit on a typical integrated circuit die. When built on CMOS substrates, however, on-chip antennas suffer from low efficiency, and radiate in undesirable directions because of their proximity to the substrate. The main contribution of this dissertation is a new type of on-chip dipole antenna with a rectangular silicon lens that couples the radiated energy away from the lossy substrate and focuses it into a narrow beam in the upward direction. We discuss the basic operating principles of the silicon lens, and then investigate the effect of the lens' dimensions on the antenna's performance.;The second major topic of this dissertation is the use of standing-wave oscillators as a millimeter-wave signal source. The distributed nature of standing-wave oscillators allows them to operate up to very high frequencies, while the constant phase property could be used to drive multiple antennas. We propose an integrated millimeter-wave transmitter that consists of a standing-wave oscillator driving an on-chip dipole antenna. This simplifies the testing of the on-chip dipole antenna, and also allows us to explore this new transmitter architecture.;We design a prototype 28-GHz transmitter using a low-power 65-nm CMOS process. The silicon lens is attached during testing in order to compare the antenna's performance with and without the lens. We present the transmitter's tuning range and output power, and the on-chip antenna's radiation patterns. Finally, we discuss some practical issues related to the transmitter, such as scaling, frequency tuning methods, and amplitude equalization for the standing-wave oscillator. |
