In this work, we designed and fabricated dielectric materials with predetermined dielectric permittivity. These materials are 3-D printed using fused deposition modeling technique with high impact polystyrene filament. The dielectric structure is composed of discrete layers that are separated into cells. Each unit cell is essentially a plastic cube with square air void in the center. Desired variable relative permittivity was realized by changing the filling ratio. The dependences of relative permittivity on filling ratio are measured and presented. Obtained approximated dependence of relative permittivity can be utilized for microwave lens synthesis for low-cost communication systems.