Active frequency-multiplier design using CAD

A tutorial paper on active frequency multiplier design is presented. Rough calculations for a ×2 multiplier using classical theory are developed and used as a starting point for implementation with nonlinear computer-aided design (CAD) software. The power of the nonlinear CAD software for visualizing and understanding concepts important to frequency multiplier design, and also for optimization of critical design parameters is demonstrated through realistic examples. Important design considerations for higher order multipliers are discussed, including design of output termination circuitry for a ×4 multiplier at 28 GHz.