A 60-GHz sub-harmonic IQ modulator and demodulator using drain-body feedback technique

A 50-to-62 GHz sub-harmonic IQ de/modulator using 90-nm CMOS technology is presented in this paper. A passive sub-harmonic gate mixer for both up-conversion and down-conversion simultaneously is used as the sub-circuit of this IQ de/modulator, which can achieve high isolation without baluns and quadrature phase dividers, therefore the required LO power is lower than those of other passive modulators. The modulator exhibits an up-conversion gain of -13 dB and a down-conversion gain of -15 dB from 50 to 62 GHz with LO power of 4 dBm. The 2LO-to-RF isolation is better than 40 dB. The sideband suppression is better than -20 dBc from 50 to 62 GHz.