Microwave Filters for Communication Systems: Fundamentals, Design and Applications

FOREWORD

It gives me great pleasure to write a foreword for this monumental work by three of the most prominent contemporary experts in the field of microwave filters. For more than three decades, significant research and development efforts have been focused on improving performance, introducing new concepts, and developing new technologies for microwave filters. As a result, microwave filters available today are significantly better than what was available 30 years ago: much smaller size, lower loss, flat pass bands, very high rejections, extremely steep transition response from pass band to stop band, stop band transmission zeros, symmetrical or asymmetrical responses, and possibility of self equalized group delay. In addition, the design techniques employed today are dramatically different. In the past, microwave filter designers used approximate circuit models and idealized components to produce a design. Such designs required many iterations and empirical adjustments to achieve the desired performance. Today, synthesis techniques coupled with very accurate electromagnetic simulations and sophisticated optimization software algorithms, operating on very fast computers, allow the filter designers to go from the drawing boards almost immediately to the final product, without the need for empirical adjustments or manual tuning. This cuts dramatically the time required for product development cycle. It also allows implementation of much more efficient and enhanced capacity communication ...