This book presents a new global optimization technique using Taguchis method and its applications in electromagnetics and antenna engineering. Compared with traditional optimization techniques, Taguchis optimization method is easy to implement and very efficient in reaching optimum solutions. Taguchis optimization method is developed based on the orthogonal array (OA) concept, which offers a systematic and efficient way to select design parameters. The book illustrates the basic implementation procedure of Taguchis optimization method and discusses various advanced techniques for performance improvement. In addition, the integration of Taguchis optimization method with commercial electromagnetics software is introduced in the book. The proposed optimization method is used in various linear antenna arrays, microstrip filters, and ultra-wideband antenna designs. Successful examples include linear antenna array with a null controlled pattern, linear antenna array with a sector beam, linear antenna array with reduced side lobe levels, microstrip band stop filter, microstrip band pass filter, coplanar waveguide band stop filter, coplanar ultra-wide band antenna, and ultra-wide band antenna with band notch feature. Satisfactory results obtained from the design process demonstrate the validity and efficiency of the proposed Taguchis optimization method.