A 30-60 GHz sub-harmonic IQ de/modulator using TSMC CMOS 0.13-μm process is presented in this paper. The IQ de/modulator consists of two FET resistive mixers, a 90° coupler, and a Wilkinson power divider. The resistive mixer could simultaneously used as a up-converted or a down-converted mixer. Therefore, the measurement of the FET resistive mixer based modulator or demodulator will be done. The die size is 0.78 mm × 0.58 mm. Both IQ demodulator and modulator feature the conversion loss of - 16±1 dB and good demodulation and modulation capacity.