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W. Perndl:
"Monolithic Microwave Integrated Circuits in SiGe:C Bipolar Technology";
Supervisor, Reviewer: A.L. Scholtz, P. Weger; Institut für Nachrichtentechnik und Hochfrequenztechnik, 2004.

This thesis deals with design and optimization of monolithically integrated circuits for applications at microwave frequencies fabricated in a state-of-the-art low-cost silicon germanium (SiGe) bipolar technology. The rapid growth of the communication market is enabled due to low-cost high-frequency solutions. Especially wireless applications like wireless local area networks (WLAN), global positioning systems (GPS) and mobile telephony (GSM and UMTS) as well as wireline broadband systems came up over the past years. Additionally, applications at microwave frequencies like distance sensors for automotive and industrial systems as well as high-speed data communication could become a new mass market, if system costs can be reduced significantly. For monolithically integrated realization of such systems, silicon germanium bipolar technologies seem to be a promising candidate. Due to constant progress in technology development as well as accurate optimization during the circuit design process, monolithic integrated circuits in the microwave frequency range fabricated in low-cost silicon-based technologies become feasible.

At the beginning of this thesis an overview of the SiGe:C bipolar technology, in which the chips of this work have been fabricated, is presented. Subsequently, monolithic integration of analog building blocks is demonstrated on the basis of three representative circuits for different microwave applications.

The first circuit presented in this work is a broadband amplifier. The amplifier is intended for multiple applications like a preamplifier of high data rate signals, an amplifier for high-frequency single-tone signals and a linear amplifier in conventional high-frequency systems. Due to contradicting requirements of the different applications, tradeoffs between circuit parameters are necessary. A flat frequency response and a high 3-dB bandwidth are the main design targets. By careful optimization of the circuit, outstanding measurement results up to 100 Gbit/s are achieved. This is the highest bit rate for analog high-frequency circuits published so far for silicon-based as well as GaAs and InP technologies.

The second example of a fully monolithically integrated microwave circuit is a down-conversion mixer in the frequency range from 76 GHz to 81 GHz. This frequency band is intended for automotive distance sensors. With this design, a monolithically integrated active down-conversion mixer for microwave frequencies around 77 GHz is demonstrated for the first time in silicon-based technologies.

Finally, a voltage-controlled oscillator is shown. The main design target is to reach an output frequency as high as possible at reasonable values of phase noise and output power. By means of a quarter-wave transformer at the output of the circuit an operation frequency up to 98 GHz is reached.