© 2018 IEICE The high permittivity dielectric substrate having advantages in point of the miniaturization and matching with the transmission wave was applied to the NRD-guide Schottky barrier diode mount instead of the low permittivity one. Guided modes in the vertical strip transmission line consisting of the high permittivity dielectric substrate were investigated to eliminate the undesired modes and to design the choke circuit. The mount consists of the choke circuit and was applied to the up converter. And the experimental model of proposed mount was made. Its return loss was measured and was compared with the calculated one.