A novel high performance SMT (surface mount-type) ceramic package is proposed in this paper. In order to improve the transmission properties of the package, several key points of the simulation and design technologies for high frequency SMT package are proposed. The package has a surface mount terminal with a coplanar structure. The hermetic SMT package prototype samples are manufactured and measured. The measured results show the return loss below -20dB and the low insertion loss less than 0.6dB in the frequency range from DC to 40GHz. It is confirmed that this surface mount-type package shows high transmission properties as well as high thermal and mechanical reliability.