Rohde & Schwarz’s Novel Broadband Amplifier Product Line Leverages Microwave Office Software for the Design and Optimization of Key Components
Rohde & Schwarz is a leading supplier of solutions for test and measurement, broadcasting, radio monitoring and radiolocation as well as mission-critical radiocommunications. Established more than 75 years ago, R&S is a privately owned company with a global presence and a dedicated service network in more than 70 countries worldwide. Corporate headquarters are in Munich, Germany.
The Design Challenge
The R&S®BBA 100 broadband amplifier series is a family of highly reliable state-of-the-art broadband amplifiers comprising various power stages and frequency ranges. These broadband amplifiers are suitable for a variety of applications in EMC environments, communications, research and physical engineering. The R&S®BBA 100 is outstanding in many respects. It is the first completely modular RF power amplifier system on the market. The base unit can accommodate up to four amplifier modules with different power and frequency ranges. Comprehensive systems can be implemented by means of extension units connected to the base unit; the system is then installed in 19" racks. This modularity makes it possible to tailor an R&S®BBA 100 system to meet application-specific requirements with regard to output power and frequency range. Frequency ranges within an overall span from 9 kHz to 1 GH z and output power up to 500 W are provided. While developing this innovative product, R&D had to solve various and challenging RF tasks.
AWR Microwave Office was used to develop major components within the R&S®BBA 100, including two broadband couplers that play a key role in the design. One coupler is used to couple out the power of the current forward signal and the reflected signal of the amplifier system. This data is used for measurement purposes, i.e, to enable important protection functions for the amplifier as well as to provide an indication of the forward and reflected signal and the VSWR in the graphical user interface. The other coupler is used to couple amplifier modules with identical frequency and output power for the purpose of attaining a higher RF output power and enabling scalability of the system according to customer and project requirements.
Microwave Office was an indispensable tool in designing key components within the final product line. The basic dimensioning of the couplers was determined by means of simulation, and an iterative approach between simulation and stepwise optimization led to the final successful design. The simulations allowed the effects of parameter changes to be recognized early on, and helped to optimize the design of the couplers. Additionally, AWR's TestWave™ software was used to provide connectivity of the Microwave Office design environment with vector network analyzer test equipment. This set-up was extensively used to read S1P and S2P parameter files from vector network analyzer equipment into the Microwave Office design environment, which produced a good alignment between measurements and the simulation environment and saved valuable time during the development process.
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