Interactions of electromagnetic fields with materials at high frequencies have given rise to a vast array of practical applications in industry, science, medicine, and consumer markets. Applicators or probes, which are the front end of these systems, provide the field that interacts with the material. This book takes an integrated approach to the area of high frequency applicators and probes for material interactions, providing a toolkit for those who design these devices. Particular attention is given to real-world applications and the latest developments in the area. Mathematical methods are provided as design tools, and are often simplified via curve-fitting techniques that are particularly usable by handheld calculators. Useful equations and numerically solved examples, using situations encountered in practice, are supplied. Above all, this volume is a comprehensive and useful reference where the reader can find design rules and principles of high frequency applicators and probes for material processing and sensing applications. Electronic and electrical R&D engineers, physicists, university professors and students will all find this book a valuable reference.