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W. Bakalski:
"Integrated Microwave Power Amplifiers";
Supervisor, Reviewer: A.L. Scholtz, G. Magerl; Institut für Nachrichtentechnik und Hochfrequenztechnik, 2003.

Abstract

New wireless communication systems like wireless local area networks (wireless LAN, WLAN), satellite communications, wireless point to multipoint radio links, etc. lead to increasing efforts in the development of high-speed semiconductor technologies and RF circuits for these applications. Due to the demand for low-cost solutions and iniaturization, technologies enabling the complete monolithic integration of major RF building blocks on single semiconductor chips are strongly preferred. One of the key RF building blocks is the power amplifier (PA). Due to its position in front of the antenna, is has to fulfill several needs standing in contrary to each other: Low power consumption but high output power levels, or high transistor robustness and high speed efforts or high linearity and high efficiency. Another important task comes from the economic side: Expensive housing or matching networks are not wanted, but a high efficiency is required to face the market. A major limiting factor is the limited quality factor of on-chip passives. So some design techniques have to be considered to relax the limitations. All this, and accurate models for the transistors as well, are required to optimize the design.
The main results are:
- A highly integrated 2.4 GHz ISM PA with a minimum of external components
is presented. It shows outstanding efficiency performance of over 50% at 2V of supply voltage.
- The first fully-integrated wireless 5.3 GHz LAN PA in SiGe-bipolar technology
is developed. It fulfills the needs on linearity and is free of any external matching components including DC-block capacitors. Further it shows almost perfect input and output matching. It features efficiency levels comparable with solutions requiring expensive external networks or ceramics.
- The first fully integrated SiGe-bipolar PA working up to 18 GHz is reported.
It features as well all matching components integrated on-chip.
It is an example for the technological limits as it rises up to an fT /fop of only about 4.2. It is further an example for the limits in the usage of on-chip transformers.