High-Performance RF-ASICs

Fraunhofer Institute for Integrated Circuits

Professional industrial applications require customer specific solutions, since commercially available ICs do not meet the demands regarding form factor, electric characteristics and functionality.

Based on state-of-the-art compound semiconductors and SiGe Bipolar technologies, we develop integrated solutions providing maximum performance.

Broadband IQ Modulator

The extremely high demands on components utilized in measuring instruments are often not met by commercially available devices. For Rohde & Schwarz, a German manufacturer of test and measurement equipment, Fraunhofer IIS developed broadband IQ modulator ASICs meeting the demands of frequency range, modulation bandwidth, linearity and noise.

Besides 1 GHz and 4 GHz modulators in GaAs-MESFET technology, an 8 GHz chip was implemented in GaAs-HEMT technology representing one of the key components of high-end vector signal generator R&S SMU200A. The IQ modulator chip works in the frequency range from 200 MHz to 8 GHz.

From the first feasibility studies to series production, the project was performed in close cooperation with Rohde & Schwarz. Besides the actual IC design, the project comprised the selection of the suitable semiconductor technology, application-specific packaging and the implementation of production testing. Fraunhofer IIS coordinates the IQ modulator production and delivers the tested chips exclusively to Rohde & Schwarz.

Wireless Tracking WITRACK

Our 3D localization system WITRACK is able to localize objects where satellite-based systems can not be employed due to insufficient accuracy. Hence, autonomous, miniaturized transmitters are implemented in the objects to be observed. The area to be observed, e. g. a soccer stadium, is provided with a special receiver infrastructure. The miniaturized transmitter is based on two ASICs implemented in SiGe BiCMOS technology and developed by Fraunhofer IIS. An integrated, configurable 200 MHz Burst Controller operates the transmitter and generates the digital base band signals.

The highly integrated, broadband 2.4 GHz RF transmitter converts the base band to the radio frequency and delivers the signal directly to the antenna. The RF ASIC consists of base band DA converters, IQ modulator, the power amplifier and a completely integrated PLL with VCO.

Linearization of Power Amplifiers

Fraunhofer IIS worked successfully on the research project »Linearization of HF Power Amplifiers for Mobile Radio Systems of the Third Generation« initiated and funded by the German Ministry of Education and Research. Focus was on the development of a linearization system for UMTS base stations based on the principle of adaptive analog predistortion.

Measurements with W-CDMA signals showed a suppression of the adjacent channel power of up to -55 dBc. In order to achieve the highest possible integration of the linearization system, the complete RF part was implemented on a single GaAs-HBT chip. The resulting demonstrator showed the capability of this linearization process for UMTS and further applications.

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