Electronically Reconfigurable Circuits for Millimeter-Wave and Beyond
Millimeter-wave (mm-Wave) wireless communication systems often employ phased array architecture to overcome the high path loss and to provide spatial selectivity. As the number of elements in the array increases, the complexity as well as physical area required for the circuitry also increase. This calls for circuit blocks that are multifunctional and can be electronically reconfigured. This dissertation presents the analyses, designs and implementations of electronically reconfigurable circuit blocks that operate bidirectionally and at multiple frequency bands.
The first part of the dissertation discusses three mm-Wave reconfigurable circuit blocks realized using the constructive wave amplification technique (CCWA) in both SiGe BiCMOS and CMOS SOI processes. First, a power amplifier is designed at 60 GHz in a 0.12-μm SiGe BiCMOS process that incorporates a CMOS-bipolar cascode (BiFET) feedback circuit topology. Second, a dual Q- and W- band, bidirectional amplifier is demonstrated in a 45-nm CMOS SOI process where operations at different bands and directions are realized by electronically config- uring the feedback “field of FETs”. The bidirectional concept is then extended to the design of a three-port V-band reconfigurable active circulator that directs traveling waves between different pairs of ports while providing isolation from the remaining ports.
Secondly, a switchless bidirectional front-end architecture is demonstrated in a 90-nm SiGe BiCMOS process. The proposed architecture enables a time-division duplexed (TDD) operation without the use of high-speed transmit and receive (T/R) switch. A passive transmission line matching network is used to isolate the power amplifier and low-noise amplifier and a bidirectional passive mixer is used for up- and down-conversion of the signal. The front-end is incorporated to a two-element linear coupled oscillator array to form a local oscillator beamforming transceiver.
Finally, a high-speed track-and-hold amplifier (THA) is demonstrated in a 90-nm SiGe BiCMOS process. This work demonstrates the competitiveness of advance integrated silicon processes when being benchmarked against high performance III-V processes. The continuous improvement of silicon-based transistors will allow integrated systems to operate at higher frequencies. All the circuits techniques present in this dissertation are applicable to the design at mm-Wave and beyond.