The main components of a phased array system are power distributors, antennas, and some structures to change the relative phases of the respective signals. These structures are microwave phase shifters, which can be basically defined as circuit components used to change the transmission phase angle of a network. While the most important application of microwave phase shifters is within a phased array antenna system, there are many other implementation areas such as instrumentation systems or wireless communication. In this book it is aimed to present a complete modeling and performance improvement study on a specific type of microwave phase shifters, namely distributed micro-electro-mechanical transmission line (DMTL) phase shifters. The main goals of this book are to introduce an improved modeling approach for DMTL structures and perform an improved performance DMTL phase shifter.