Solid-state circuits in BiCMOS technology for sub-THz applications

With the emerging sub-THz applications such as high-speed wireless communication, high-resolution imaging, spectroscopy, and radars systems, SiGe BiCMOS technology is the key to enabling low-cost market-oriented solutions. Unfortunately, this technology suffers from low output power, and efficiency due to the low breakdown voltage, dominant high-frequency conductor and substrate losses, and poor performance of the passive elements. In this dissertation, various subTHz solid-state circuits in BiCMOS technology are presented, with emphasis on improving their performance in terms of output power, efficiency, and bandwidth beyond state-of-the-art. Specifically, power amplifiers (PAs) and frequency multiplier chains (FMCs) are designed at sub-THz frequencies. The Design procedure and experimental results of PAs delivering an output power larger than 18-dBm are presented at 110-190 GHz frequency bands. Besides, the design of ultra-broadband FMCs acting as frequency 8th tuplers above 220 GHz is discussed. The FMCs contain fully integrated input balun, frequency doubler and quadrupler, PAs, and a filter. The experimental results of FMCs demonstrating record 3-dB bandwidth of 127 (223-350) GHz, and 72 (294-366) GHz with peak output 2.3 and 2.5 dBm, respectively are presented. Moreover, the design of broadband passive structures such as baluns, and onchip antenna are presented. In the design of baluns, three asymmetric coupled lines are used to improve the odd mode capacitances, which increase the even/odd mode impedance ratio over a wider bandwidth needed for the broadband operation. Measurement results of the G-band balun, including RF pads achieving a minimum insertion loss of 1.35 dB at 137 GHz with insertion loss lower than 1.7 dB across 120-170 GHz are presented. Likewise, the design of the on-chip dielectric resonator antenna (DRA) operating at 325-390 GHz is presented. The DRA shows relative impedance bandwidth of 18.5 %, with peak gain and radiation efficiency of 10 dBi, and 75 %, respectively. The active and passive circuits presented in this dissertation are useful and can be used in the future to develop low-cost and compact systems on-chip for various THz applications.