The book 'Microwave Passive Devices and its Scattering-Matrix' has been written for engineering students. The aim of this book is to provide clear and logical information about the topics covered. The book is divided into six chapters. The first chapter 'Basics of Microwave' deals with microwave frequencies and their advantages, disadvantages and its applications. The second chapter 'Scattering Parameters' describes S-parameter and its properties. The third chapter 'Microwave Hybrid Circuits' deals with different types of hybrid circuits and its S-matrix. The fourth chapter 'Directional Couplers' provides the basics of different types of directional couplers and its S-matrix. The chapter five 'Faraday Rotation' discusses the different types of microwave devices such as: isolators, circulators, attenuators, phase shifters, terminations and their S-matrix. The chapter six covers important problems related to the covered topics.