  Within the paradigm of metamaterials and metasurfaces, electromagnetic
properties of composite materials can be engineered by shaping or modulating
their constituents, so-called meta-atoms. Synthesis and analysis of
complex-shape meta-atoms with general polarization properties is a challenging
task. In this paper, we demonstrate that the most general response can be
conceptually decomposed into a set of basic, fundamental polarization
phenomena, which enables immediate all-direction characterization of
electromagnetic properties of arbitrary linear metamaterials and metasurfaces.
The proposed platform of modular characterization (called "materiatronics") is
tested on several examples of bianisotropic and nonreciprocal meta-atoms. As a
demonstration of the potential of the modular analysis, we use it to design a
single-layer metasurface of vanishing thickness with unitary circular
dichroism. The analysis approach developed in this paper is supported by a
ready-to-use computational code and can be further extended to meta-atoms
engineered for other types of wave interactions, such as acoustics and
mechanics.
