Presented is 24 Gbit/s wireless data transmission at 300 GHz using a uni-travelling carrier photodiode (UTC-PD) emitter and Schottky barrier diode detector, which were designed and fabricated for larger bandwidth. Both the emitter and the detector were fabricated on the same epi-layer of the UTC-PD. At the link distance of around 50 cm, a bit error rate of less than 1 x 10(-10) has been achieved with the transmitted power from the UTC-PD of less than 200 mu W and effective antenna gains of 40 and 35 dBi in the emitter and detector sides, respectively.