The RO4700 laminates from Rogers Corporation are antenna-grade laminates, fully compatible with conventional FR-4 and high temperature lead-free solder processing and do not require the special treatment needed on traditional PTFE-based laminates for plated through hole preparation. These laminates have a dielectric constant (Dk) of 2.55 and 3.0 and a loss tangent (Df) of 0.0022 measured at 2.5 GHz. They have low insertion loss and low PIM performance, with values better than -160 dBc.
The resin systems of the dielectric material used in this laminate provides the properties necessary for ideal antenna performance. The coefficients of thermal expansion (CTEs) in both the X and Y directions are similar to that of copper. The good CTE match reduces stresses in the printed circuit board antenna. The typical glass transition temperature of these materials exceeds 280°C (536°F), leading to a low Z-axis CTE and excellent plated through hole reliability. These laminates are ideal for base station antennas.