Design methods for 60GHz beamformers in CMOS

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The 60GHz band is promising for applications such as high-speed short-range wireless personal-area network (WPAN), real-time video streaming at rates of several-Gbps, automotive radar, and mm-Wave imaging, since it provides a large amount of bandwidth that can freely (i.e. without a license) be used worldwide. However, transceivers at 60GHz pose several additional challenges over microwave transceivers. In addition to the circuit design challenges of implementing high performance 60GHz RF circuits in mainstream CMOS technology, the path loss at 60GHz is significantly higher than at microwave frequencies because of the smaller size of isotropic antennas. This can be overcome by using phased array technology. This thesis studies the new concepts and design techniques that can be used for 60GHz phased array systems. It starts with an overview of various applications at mm-wave frequencies, such as multi-Gbps radio at 60GHz, automotive radar and millimeter-wave imaging. System considerations of mm-wave receivers and transmitters are discussed, followed by the selection of a CMOS technology to implement millimeter-wave (60GHz) systems. The link budget of a 60GHz WPAN is analyzed, which leads to the introduction of phased array techniques to improve system performance. Different phased array architectures are studied and compared. The system requirements of phase shifters are discussed. Several types of conventional RF phase shifters are reviewed. A 60GHz 4-bit passive phase shifter is designed and implemented in a 65nm CMOS technology. Measurement results are presented and compared to published prior art. A 60GHz 4-bit active phase shifter is designed and integrated with low noise amplifier and combiner for a phased array receiver. This is implemented in a 65nm CMOS technology, and the measurement results are presented. The design of a 60GHz 4-bit active phase shifter and its integration with power amplifier is also presented for a phased array transmitter. This is implemented in a 65nm CMOS technology. The measurement results are also presented and compared to reported prior art. The integration of a 60GHz CMOS amplifier and an antenna in a printed circuit-board (PCB) package is investigated. Experimental results are presented and discussed.