CIRCUIT DESIGN FUNDAMENTALS introduces the RF (ratio frequency) microwave circuit design fundamentals. The book consists of eleven chapters, including RF concepts lumped component models, Filters and resonant circuits, transmission line theory, Impedance matching technique, The Smith Chart and its Application, Signal Flow Graphs, Small-Signal Amplifier Design, Power Divider, Combiner and Coupler, PIN Diode Circuits, Application for power amplifier design and Electromagnetic Compatibility of Integrated Circuits, reflecting basic theories in the areas. What's more some useful examples can be applied in the actual designs. This book will be useful not only for graduates but also to help the engineers and researchers.