This is a practical guide and introduction to the design of key RF building blocks used in high data rate transmitters. The emphasis lies on CMOS circuit techniques applicable to oscillators and upconvertors. Furthermore, a method for RF-specific design automation is exemplified by the CYCLONE tool for automated LC-VCO synthesis. The accuracy of a simulation depends strongly on the models used for the passive and active components. Therefore, a chapter on practical RF simulation models for MOST devices and planar inductors is included. Polyphase networks can be used for quadrature signal generation and as a complex filter. The book describes in detail the analytical calculations on such networks and includes a practical simulation-based design approach. The final manufacturing step before measuring a chip is the bonding process. In a short chapter the flip-chip bonding technique is discussed and the negative influence of X-ray inspection on chip performance is demonstrated. High data rate systems need low phase-noise oscillators. The design of a 17GHz VCO as presented in this book demonstrates the possible use of a CMOS technology for fixed-wireless or high-speed optical system integration. Using a polyphase network as a complex filter, a ringoscillator with over a decade of tuning range has been linearized for use in HFC-like cable systems. This technique is discussed elaborately in a chapter on broadband oscillators. As a typical design case of a high data rate building block, the design of a wideband CMOS transmitter circuit is presented. Starting from a market overview, the target specifications are derived. A high-level circuit design is then gradually refined down to transistor level and ultimately layout. In a concluding chapter, the measured performance is discussed.