Abstract: The design of a 0.22 THz sub-harmonically pumped mixer circuit was demonstrated. The circuit was based on anti-parallel pair of planar Schottky diodes from the CETC 13 with the co-simulation of electromagnetic(EM) software and circuit software. The conversion loss was measured at the fixed intermediate frequency(IF) of 10 MHz. The double sideband(DSB) conversion loss is less than 15 dB in the range of 175 GHz to 235 GHz, the bandwidth is 60 GHz. The best DSB conversion loss is 8.5 dB at 196 GHz. The measured result was well with the simulated result. The DSB equivalent noise temperature of is 1 200 K at 216 GHz with the local oscillator(LO) power of 5.7 mW.