Design of 40-108-GHz low-power and high-speed CMOS up-/down-conversion ring mixers for multistandard MMW radio applications

In this paper, a pair of broadband, low-LO-power, low-dc-power, and high-speed up/down-conversion ring mixers are presented for multistandard millimeter-wave (MMW) radio applications. By employing a weak inversion biasing technique, the ring mixer can operate at a low LO drive level and low dc power while maintaining reasonable conversion gain performance. In addition, an IF transimpedance amplifier (TIA) buffer and wideband RF design are introduced to increase the operation speed of the mixer for MMW wireless Gigabit transmission. Using a 90-nm CMOS low-power process, the up-/down-conversion ring mixers are designed and fabricated based on the presented topology. The down-conversion ring mixer and up-conversion ring mixer exhibit flat measured conversion gain of -1 ± 2 dB and 0 ± 2 dB from 40 to 110 GHz and 40 to 108 GHz, respectively. After biasing the transistors of the ring mixer core at weak inversion region, the presented down-conversion and up-conversion ring mixers can operate at low LO drive power, -2 and 0 dBm, respectively, even up to 100 GHz. For MMW wireless gigabit communication, gigabit binary phase-shift keying modulation signal test is successfully performed through a direct-conversion system in this work. The presented ring mixers are suitable for 60-GHz wireless personal area network, E -band (71-76 GHz, 81-86 GHz, and 92-95 GHz) wireless fiber, and 77-GHz anti-collision radar applications.