Millimeter and Sub-Millimeter Wave Integrated Active Frequency Down-Converters

Doctoral thesis, 2015

In recent years, the increasing amount of data transmission, the need for automotive radars, and standoff imaging for security applications are the main factors that accelerate research in the millimeter and sub-millimeter wave frequency ranges. The semiconductor industries have continuously developed their processes, which have opened up opportunities for manufacturing monolithically integrated circuits up to a few hundred GHz, based on transistor technologies. In this thesis, a 100 nm GaAs mHEMT technology, a 250 nm InP DHBT technology, and a 130 nm SiGe BiCMOS technology, which show a typical ft / fmax of 200/300 GHz, 375/650 GHz, and 250/400 GHz, respectively, are verified for analog circuit design. In the above mentioned applications, the frequency mixer is one of the most important components. Consequently, a study of millimeter/submillimeter wave mixers is important for the choice of technology and topology. Aiming for either the next generation of high-speed communication or standoff imaging applications, different mixer topologies are studied, designed and fabricated as candidates for further integration in receivers. The presented mixer topologies include the self-oscillating mixer, the resistive FET mixer, the Gilbert mixer, and the transconductance mixer. All these topologies have been realized in given technologies, and cover the frequencies around ~145 GHz, ~220 GHz, and ~340 GHz. The designed 340 GHz Gilbert mixer with IF buffer amplifier and on-chip patch array antenna demonstrated the first fully integrated receiver in HBT technology at such high frequencies as well as a reasonable noise figure of 17 dB. A novel 110~170 GHz transconductance mixer is characterized in ×1, ×2, ×3, and ×4 harmonic mixing modes, which allows for flexibility in the overall system design. Apart from the mixer designs, a transceiver, which operates as an amplifier for transmitting and simultaneously as a down-converting mixer for receiving, is designed for the frequency range of 110~170 GHz, aiming for sub-cm resolution in multipixel standoff imaging systems. It is successfully demonstrated in a FMCW radar setup for distance measurements.