Substrate integrated waveguide (SIW) technology is a twenty-first century transmission line that has evolved recently to open new doors to the development of efficient circuits and devices operating in the microwave and millimeter-wave frequency range. Microstrip circuits and devices are inefficient at high frequency applications and require very stringent manufacturing tolerances when used to implement microwave and millimeter-wave components. This is as a result of the fact that wavelengths are short at higher frequencies. Waveguide circuits and devices are preferred for higher frequency applications, but they are expensive and difficult to manufacture. It is also very challenging to integrate a waveguide device with planar devices in its vicinity. The SIW bridges the gap between the traditional air-filled waveguide and planar transmission lines such as microstrip. Practical Approach to Substrate Integrated Waveguide (SIW) Diplexer: Emerging Research and Opportunities is an essential reference source that discusses the development of efficient circuits and devices operating in the microwave and millimeter-wave frequency range through the use of substrate integrated waveguides. Featuring research on topics such as microstrip resonators, circuit model analysis, and quality factor extraction, this book is ideally designed for researchers, engineers, scientists, developers, scholars, practitioners, educators, policymakers, and students.