This work was funded in part by the Predoctoral Grant FPU18/01965 and in part by the
financial support of BBVA Foundation through a project belonging to the 2021 Leonardo Grants for
Researchers and Cultural Creators, BBVA Foundation. The BBVA Foundation accepts no responsibility
for the opinions, statements, and contents included in the project and/or the results thereof, which
are entirely the responsibility of the authors.Metamaterials are artificially engineered devices that go beyond the properties of conventional
materials in nature. Metamaterials allow for the creation of negative refractive indexes;
light trapping with epsilon-near-zero compounds; bandgap selection; superconductivity phenomena;
non-Hermitian responses; and more generally, manipulation of the propagation of electromagnetic
and acoustic waves. In the past, low computational resources and the lack of proper manufacturing
techniques have limited attention towards 1-D and 2-D metamaterials. However, the true potential of
metamaterials is ultimately reached in 3-D configurations, when the degrees of freedom associated
with the propagating direction are fully exploited in design. This is expected to lead to a new era in
the field of metamaterials, from which future high-speed and low-latency communication networks
can benefit. Here, a comprehensive overview of the past, present, and future trends related to 3-D
metamaterial devices is presented, focusing on efficient computational methods, innovative designs,
and functional manufacturing techniques.Predoctoral Grant FPU18/01965BBVA Foundatio
