60-GHz Dual-Conversion Down-/Up-Converters Using Schottky Diode in 0.18 Foundry CMOS Technology

摘要

Due to the benefits of Schottky diodes, 0.18- $mu{hbox {m}}$ CMOS technology is being promoted for millimeter wave applications. In this paper, 60-GHz dual-conversion down-/up-converters using Schottky diodes are realized by using 0.18-$mu{hbox {m}}$ foundry CMOS technology. A ${hbox {CoSi}}_{2}{hbox {--Si}}$ Schottky diode, fabricated on a lower doped N-well by blocking the threshold voltage adjustment implant, has a lower reverse leakage current and a better ideality factor. Thus, it is ideal for the 60-GHz sub-harmonic mixer design. Two new types of Schottky-diode mixers, a down-conversion sub-harmonic mixer with a dual-band lump-distributed phase-inverter rat-race coupler and an up-conversion sub-harmonic mixer with a trifilar transformer, are realized and employed at the high-frequency conversion stage of the dual-conversion architecture to achieve small size and broadband isolations. The silicon-based Schottky diode with a low turn-on voltage offers great advantage in LO pumping power, especially for an antiparallel diode pair structure. In our Schottky-diode sub-harmonic mixers, the required LO power is only 1 dBm. The dual-conversion down-converter achieves 5-dB conversion gain and 19 dB noise figure under $V_{dd}=2.5 {rm V}$ and $I_{dd}=22 {hbox {mA}}$, and the dual-conversion up-converter, with $V_{dd}=2.5 {rm V}$ and $I_{dd}=26 {hbox {mA}}$, attains greater than 40-dB sideband rejection and $-$1 dB conversion gain over th- whole 60-GHz bandwidth.