About Ferdinand-Braun-Institut, Leibniz-Institut fuer Hoechstfrequenztechnik

We research cutting-edge technologies in the fields of microwave technology and optoelectronics. For customers in industry and science we provide high-frequency devices and circuits for communication and sensor technology as well as high-power diode lasers for materials processing, laser technology, medical technology and high precision metrology.
As a competence center for III/V-compound semiconductors we operate industry-compatible and flexible clean room laboratories with 2″-4″ gas phase epitaxy units and a 2″-4″ process line.

Mission and Aims

Our mission is application-oriented research in the fields of microwaves and optoelectronics in close cooperation with industry. Our research work includes the complete spectrum from computer-aided design and material and process technologies to devices, circuits and systems.
Our institute bridges the gap between research and application by making its results available to customers in the research community and industry.
Our research portfolio also includes basic topics, which are key aspects in establishing know-how in novel fields and in maintaining leading-edge competence. At the same time, this competence forms the basis for future project funding and research contracts.

Microwave Department

The microwave department researches technologies and tools required for the development of microwave circuits and modules. In line with the general mission of the institute, the focus is on III-V semiconductor technologies (GaN, InP) and power applications.
The activities within the department comprise the following four main topics:

Electromagnetic Field Simulation and Applications
Electromagnetic simulations have become an indispensable tool for the design of microwave circuits and modules. FBH has been working on 3D EM simulation methods and their applications for more than 20 years, both for internal use and for external partners. We offer optimized solutions tailored to the customer’s needs and provide in-depth understanding of the phenomena present.

Circuit Design and Device Modeling
Circuit design and device modeling is a key competence in developing MMICs. We focus on GaN-based power amplifiers up to X-band and InP-HBT circuits for W-band and sub-THz frequencies. These efforts are complemented by work on large-signal transistor descriptions for GaN HEMTs and InP HBTs as well as on modeling of passive elements.

Microwave Measurements
For characterization of devices and circuits as well as for model verification, the FBH relies on high-level measurement equipment and a dedicated group.

Microwave Packaging
As is essential for power components, the devices can be packaged in-house. The FBH activities comprise flip-chip and backside mounting, housing and board fabrication.

Microplasmas

Microwave plasma generation, particularly in the 2.45 GHz ISM band, enables a variety of new applications in medicine, biology, semiconductor industry and industrial surface engineering. The field of low-pressure plasma processing, which is widely used in industry, is permanently demanding for refinements and improvements in terms of quality, efficiency and cost. On the other hand, the new emerging field of atmospheric microplasmas is gaining more and more attention due to its high potential in creating new plasma applications as well as the chance to transfer low-pressure plasma applications to much more cost-effective atmospheric processes. In both fields, application of microwave frequencies today is limited by shortcomings of the available magnetron power-sources and by the problems associated with the microwave transmission from the source into the plasma. There is a need for an integrated semiconductor-based power source – electrode systems that are reliable and can be easily integrated in application systems. Particularly the high potential of efficient high-density atmospheric microplasma sources can be addressed only if small integrated sources become available. Thus, this field represents an interesting application and extension of the FBH activities on microwave III-V power components.

Microwave Measurements

For characterization of devices and circuits as well as for model verification, FBH relies on high-level measurement equipment and a dedicated group. The following measurements are covered:

• S parameter measurements 20 kHz to 110 GHz
• Noise characterization including low-frequency noise
• Phase-noise characterisation
• Load-pull measurements of high-power transistors (2-10 GHz, 10+ W)
• Thermal impedance measurements

These procedures are routinely performed within the current research activities. The FBH expertise, however, is also available for external partners and customers in the framework of projects
and contracts (consulting, measurement).