Fundamental to microwave device design is knowing the electromagnetic performance of materials used in the device. Whether it is a microwave substrate, an antenna radome, or an electromagnetic inference absorber, methods are needed to evaluate materials and determine their intrinsic dielectric and magnetic properties. Designers use these intrinsic parameters (permittivity and permeability) to develop or optimize microwave and RF components. Measuring the performance of microwave materials requires a system that includes i) a measurement fixture and ii) a microwave analyzer. The fixture and the analyzer are usually connected with microwave or radio frequency (RF) cables.