Complementary media predicted by transformation acoustics provide a powerful route to acoustic wave manipulation through deterministic spatial cancellation. However, their experimental realization in airborne acoustics has remained elusive due to the stringent requirement of simultaneously engineering spatially varying negative effective mass density and bulk modulus. In this paper, we implement a step-layered double-negative metamaterial (SLDNM) to construct a complementary-media-based acoustic superscatterer. The required extreme effective parameters are successfully realized via the overlapping excitation of monopolar and dipolar resonances within each layer of the SLDNM. We tailored the scattering boundary of the complementary-media-based acoustic superscatterer deterministically in experiments, creating a virtual boundary three times larger than its physical size at 800 Hz in a two-dimensional airborne sound waveguide. Upon integration with the complementary-media-based acoustic superscatterer, we further experimentally demonstrated omnidirectional radiation suppression of a dipolarlike source placed at the virtual boundary. This work fills a longstanding gap between theoretical proposals and experimental realizations of complementary media in acoustics.

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• Acoustic wave phenomena
• Mechanical & acoustical properties
• Negative refraction
• Acoustic metamaterials
• Acoustic techniques
• Effective medium approach
• Finite-element method