Juhrig, AndreAndreJuhrigSchmidt, UlrikeUlrikeSchmidtWolf, MarioMarioWolfKühnicke, ElfgardElfgardKühnickeGünther, Paul A.Paul A.GüntherGebhardt, SylviaSylviaGebhardt2022-03-142022-03-142019https://publica.fraunhofer.de/handle/publica/40700110.1109/ULTSYM.2019.8926051Scanning Acoustic Microscopes for nondestructive imaging commonly use strong focusing single element probes with center frequencies up to 230 MHz. Depending on the test scenario and the materials a resolution down to 10 mu m is reachable. This high resolution means a small extension of the sensitivity zone in lateral and axial direction and leads to the necessity of multiple C-Scans for the inspection of a volume. Using an annular-array transducer, the focal point can be shifted in axial direction. Thus, multiple scans in different depth can be replaced by a single scan. To achieve a comparable resolution to strong focused single element transducers it is necessary to increase the center frequency of annular-array transducers. So we present a prototype of a probe, that contains a planar annular-array transducer with a center frequency of 20 MHz and an aperture of 5.4 mm, separated into four quartered rings (16 elements). The characterization of the sound field, using a spherical reflector, shows a sensitivity zone with a lateral extension of 300 mu m for focusing without a lens.enannular-arraymicroscopytransducer620666conference paper