Optimized test PCBs for SAW/FBAR RF filters

The characterization of the precise performance of packaged SAW RF filters is an extremely difficult task, due to their high complexity and high performance. If printed circuit boards (PCB) for testing the filters are not carefully designed, they presumably show parasitic effects influencing the measurement results of the overall system consisting of PCB, and filter. Actually, commonly used application environments exhibit different electromagnetic properties, and so the characterization may not be valid. This paper presents a new approach to design physically different PCB in such a way that SAW RF components exhibit identical performance. The new approach is based on the concept of using optimized test environments, i.e., test environments with minimal reflections, minimal crosstalk, and minimal losses, in order to obtain the pure filter characteristics. The applicability and advantages of the new approach are exemplified.