Engineered Metamaterial for Acoustic Cloaking
Navy SBIR FY2008.2

Sol No.: Navy SBIR FY2008.2
Topic No.: N08-191
Topic Title: Engineered Metamaterial for Acoustic Cloaking
Proposal No.: N082-191-0275
Firm: Physical Optics Corporation
Applied Technologies Division
20600 Gramercy Place, Bldg.100
Torrance, California 90501
Contact: Keehoon Kim
Phone: (310) 320-3088
Web Site:
Abstract: To address the Navy need for acoustic cloaking, Physical Optics Corporation (POC) proposes to develop a new Engineered Metamaterial for Acoustic Cloaking (EMAC) technology. It is based on directional density and compressibility variation with a unique structure construction. The innovations in the EMAC sublevel structure offer the Navy a 3D acoustic cloaking spherical shell capable of enclosing various objects, and eventually an elongated 3D shell for objects such as submarines. The EMAC constituents adjust directional properties to change density and compressibility, providing an anisotropic mass density with principal axes and a radially dependent bulk modulus. In Phase I POC will develop a physical model for EMAC, a validation model, a set of optimized parameters for EMAC fabrication/design appropriate for Navy acoustic cloaking applications, and demonstrate a functional component(s) of the EMAC. Based on the feasibility demonstration, in Phase II, POC plans to develop an optimized model of EMAC materials to exhibit cloaking properties at Navy acoustic frequencies and to fabricate a laboratory proof-of-concept prototype demonstrating the ability to manufacture metamaterials in small lots.
Benefits: The proposed EMAC technology not only addresses the major Navy need for acoustic cloaking for underwater vehicles/submarines, but also has significant commercial applications for sound propagation control in airports, subway and railway stations, conference rooms, classrooms, offices, homes, and concert halls, etc., especially in the areas where keeping super-level of silence is essential.