Additive manufacturing of resonant metasurfaces for noise cancellation

A method, comprising:

• obtaining, by a system comprising a processor, a frequency value representative of a frequency of an acoustic wave to cancel, the frequency value obtained using a peak frequency detector configured to measure a dominant narrowband peak in noise generated by a cooling fan of at least one server;
• determining, by the system, dimensions of a unit cell that resonates at the frequency value, wherein the dimensions of the unit cell comprise deep subwavelength values relative to a wavelength of the acoustic wave to cancel, the determining comprising executing frequency-to-resonator parameter logic implemented by the processor to compute a chamber volume and a neck port geometry of the unit cell based on the frequency value;
• and
• controlling, by the system, a device to construct the unit cell, the unit cell when constructed comprising a solid structure, an air chamber encased in the solid structure and a hollow neck port that extends through the solid structure and is coupled to the air chamber to expose the air chamber to air.

A metasurface, comprising:

• a base structure;
• and
• a group of respective unit cells contained by the base structure,
• wherein the respective unit cells comprise respective Helmholtz resonators comprising respective air chambers coupled to respective neck ports that extend to a surface of the base structure to facilitate air flow to the respective air chambers,
• wherein the respective unit cells are configured with respective deep subwavelength dimensions relative to wavelengths of incoming acoustic waves having a specific frequency value within a narrowband frequency range corresponding to a measured peak noise frequency generated by a cooling fan of at least one server, and
• wherein the deep subwavelength dimensions are selected to resonate the respective unit cells at the specific frequency value to collectively phase cancel the incoming acoustic waves when exposed to the incoming acoustic waves emanating from the at least one server.