Design of Integrated Power Amplifiers in SiGe Technology for Mobile Terminal Applications Entwurf von integrierten Leistungsverstärkern in SiGe-Technologie für Mobilfunkanwendungen

The thesis demonstrates the design of high frequency SiGe bipolar integrated power amplifiers (PAs) for mobile communication terminals with the support of electromagnetic (EM) simulation. Three single-ended PA designs for mobile terminals operating up to 6GHz have been designed , realized and measured. The realized amplifiers fulfill the assumed requirements in terms of overall performance mainly due to the exact description of parasitics in passive networks. The EM simulation has been introduced in the design of integrated spiral inductors, transistor feeding lines, power transistor surroundings and complete matching circuits. Simultaneously the evaluation and adaptation of SiGe technology for the purposes of state of the art PA applications is being presented. The realized power amplifier designs include: • An integrated linear dual band WLAN PA for the IEEE 802.11a/b/g specification. • A three-staged linear UMTS PA intended for WCDMA application. • A dual band GSM PA with 58% power added efficiency and 35.5dBm output power in the 900MHz band. Additionally, the EM simulation introduced in chip design contributed to the development of new integrated matching structures. Practically applied for PAs, such arrangements result in an overall performance improvement. In particular the newly realized structures include: • A low-loss, high quality factor microstrip line in lossy silicon to improve linearity and efficiency of a WLAN IEEE 802.11a PA. • An integrated, modified microstrip line with defected groundplane structure to improve a 5GHz WLAN PA in terms of broadband linearity response. • Several transistor feed network realizations for a GSM PA by which the power transis-tor's robustness has been increased. With an optimized transistor feeding network, in a 2GHz WLAN PA, an increase of linearity and efficiency performance was observed.