Monolithic Micro- and Millimeter-wave Integrated Circuits in 90 nm CMOS Technology

Abstract: The objective of this work has been to design and characterize microwave components and circuits within a 90 nm RF-CMOS process. The work has been divided into two parts: integration of passive components and design and characterization of several mixer circuits. At the introductory stage, two options for implementing microstrip transmission lines are studied and compared. A novel miniature structure for baluns and power dividers is presented. This approach utilizes for the first time a triple-coupled line and offers substantial reduction in size which in turn will result in lower losses. The balun and the power divider based on this structure, have excellent phase and amplitude balance of better than 0.5 dB and 4 degrees respectively, over more than an octave bandwidth. A novel compact capacitor called fringing-field-enhanced capacitor is introduced. The proposed design makes extensive use of the fringing fields between capacitively coupled vias and offers considerable improvement in the Q-factor compared to the conventional integrated capacitors. No additional material or process steps are needed. Two single-ended resistive mixers, operating at 20 and 60 GHz, have been designed and characterized. The mixers show state-of-the-art performances with minimum conversion loss of 7.9 and 11.6 dB, respectively. It is shown that by applying selective drain bias, the intermodulation performance of the mixers, while driven by moderately low LO power, is improved. Furthermore, promising simulation results for a double balanced 60 GHz resistive mixer are presented, predicting a conversion loss of around 10 dB.