60-GHz 0.18-um CMOS dual-conversion receiver using Schottky diode mixer and slow-wave rat-race hybrid

A 60 GHz dual-conversion receiver is demonstrated using Schottky diode in 0.18-μm CMOS technology. A microwave diode mixer is employed in the first conversion while an analog passive mixer is used in the second conversion. The Schottky diode is implemented in the standard CMOS foundry without any extra photo mask steps. The high cut-off frequency of the Schottky diode helps lowering the noise figure and reduces conversion loss for the diode mixer. To further improve the noise figure and conversion loss, a slow-wave rat-race coupler is used in the Schottky diode mixer. As a result, the conversion gain is around 2 dB in the frequency range of 50~70 GHz. IP
_1dB
is 2-dBm and IIP
₃
is 22-dBm at 60 GHz. The IF bandwidth is over 1 GHz and the double-side band noise figure with respect to IF frequency is around 20 dB. The total power consumption is 55 mW at 2.5 V.