In recent years microwaves have been used extensively in radars, transmission of television programs, astronomic research, radio spectroscopy, domestic ovens and many other things. This rapid progress in microwave electronics has created an increasing demand for trained microwave engineering personnel. This book is intended for the undergraduate and postgraduate students specializing in electronics. It will also serve as reference material for engineers employed in the industry. The fundamental concepts and principles behind microwave engineering are explained in a simple, easy-to-understand manner. It can also serve as a supplemental text in a classroom, tutored, or home-schooling environment.