Flexible microwave substrates are extensively used for variety of high end microwave circuit applications such as high power solid state amplifiers, patch antennas, missile guidance, mobile base stations etc. Electrical characteristics of the microelectronic devices, such as signal attenuation, propagation velocity and cross talk are influenced by the dielectric properties of the packaging substrate. In order to meet future high-speed digital circuit designs, several materials have been developed keeping dielectric loss as minimum. Among them, PTFE-based materials are the ideal choice as base substrates for microwave circuitry with applications extending up to millimeter wave range. C-MET has successfully developed a proprietary and patented processing methodology, named as SMECH process, through which microwave circuit boards with user defined dielectric properties can be realized. These indigenously developed substrates are superior to their imported counterparts in terms of high dielectric constant (Ɛr up to 14.8), ultra low loss tangent (tan δ =0.0018) and temperature stable microwave dielectric properties. The microwave substrates technology was transferred to M/s. Speedlam Electromaterials Private Limited, Hyderabad.