Interest in utilizing additive manufacturing for RF applications has increased remarkably in recent years thanks to the potential in producing complex and lightweight parts, as well as reducing costs in manufacturing processes. However, the materials available for 3D-printing are not developed for microwave applications and thus do not have the required properties for RF applications. In this paper, we present a new composite material based on COC (Cyclic Olefin Copolymer) polymer and loaded by titanium oxide (TiO 2 ) at 36 vol%, which is perfectly compatible with the FDM (Fused Modeling Deposition) process. This new thermoplastic composite material offers high permittivity up to 9.2, low loss of 1.10-3 at 9.3GHz, and good behavior against temperature (glass transition temperature of 130°C). The CST simulation results on sub-wavelength prisms show many advantages when using this new material, mainly in reducing the component’s thickness and reducing the side lobes levels.