This thesis focuses on the design of efficient, highly integrated antennas for millimeter- wave systems. Two gaps in the exisiting literature are addressed. First, the sinuous antenna on silicon dielectric lenses is explored. The antenna is demonstrated to be an excellent option for integrated systems requiring high-gain, dual-linear polarization, and a multi- octave bandwidth. A design with cross-pol below -17 dB, polarization variations less than ±5◦, and stable impedance properties over a 4:1 bandwidth is demonstrated.

Second, silicon RFIC antennas are studied, with the goal of achieving a high level of integration and a design scalable to frequencies beyond 100 GHz. A novel solution is proposed, which uses a dielectric superstrate layer to enhance the efficiency and gain of standard patch and elliptical slot antennas. Compared to a stand-alone W-band patch in a standard CMOS process, the proposed solution yields a 7 dB improvement in antenna efficiency. Because all of the metal layers are integrated on chip and the required dielectric layer is not electrically thin, the superstrate-loaded antennas are an excellent candidate for high-efficiency on-chip antennas beyond 100 GHz.