The objective of the research is to investigate the viability of co-integrated antennas and their driving electronics on the same silicon platform for emerging radio frequency (RF)/millimeter-wave (mm-Wave) applications. Existing RF and microwave systems are mostly assembled on the board level, using commercial off the shelf (COTS) discrete components. While this allows design flexibility, transition losses and packaging complicate the overall system construction and complexity. Particularly for space-constrained applications like Internet-of-Things (IoT) radios or vehicles, board-level antennas/circuits can occupy large amounts of the area budget for a given system and may require elaborate integration techniques (e.g. multi-layer 3D integration). Furthermore, the antenna typically consumes the most area since it is much larger than its electronics at RF frequencies. On the other hand, the specifications of mm-Wave systems have driven towards higher operation frequencies, namely from 30 – 170 GHz, to provide better performance within uncongested spectra. As the antenna size decreases with increasing operation frequency, the antenna can become comparable in size to that of its driving electronics. While a substantial amount of research has focused in low-loss heterogeneous interconnects and highly efficient antenna-in-package techniques, these methods require non-trivial processing that adds to the overall system and fabrication complexity. So far, current implementations of on-chip antennas are typically inefficient due to substrate losses and thus require other unique solutions like silicon lenses or high resistivity silicon substrates. To overcome these difficulties, practical techniques to co-integrate the antenna and circuits on the same silicon platform at RF/mm-Wave while maintaining high efficiency are proposed. The dissertation provides design examples and practical guidelines of antenna and circuit co-integration on commercial silicon platforms at mm-Wave that can deliver novel performance improvements rivaling that of other more complex systems.