  This paper shows that the skin effect in systems of non-Hermitian
subwavelength resonators is robust with respect to random imperfections in the
system. The subwavelength resonators are highly contrasting material inclusions
that resonate in a low-frequency regime. The non-Hermiticity is due to the
introduction of an imaginary gauge potential, which leads to a skin effect that
is manifested by the system's eigenmodes accumulating at one edge of the
structure. We elucidate the topological protection of the associated (real)
eigenfrequencies and illustrate the competition between the two different
localisation effects present when the system is randomly perturbed: the
non-Hermitian skin effect and the disorder-induced Anderson localisation. We
show that, as the strength of the disorder increases, more and more eigenmodes
become localised in the bulk. Our results are based on an asymptotic matrix
model for subwavelength physics and can be generalised also to tight-binding
models in condensed matter theory.
