This work describes a 65 nm SOI CMOS passive mixer architecture consisting of a n-MOS cold-FET and coplanar waveguide (CPW) transmission line matching networks for six-port IQ demodulation of millimeter-wave signals. The circuit architecture avoids the use of coupler in front of the detection circuit commonly found in six-port technology. The design and fabrication of the passive mixer are described. Demodulation results and dedicated calibration procedure at 60 GHz are experimentally verified. On this basis, A 60 GHz six-port circuit is designed and manufactured with passive mixers, 90 degrees phase-shifters, active and passive dividers to build an IQ demodulator.