  In this paper, we consider very high concentration of electric field in
between infinitely many circular perfect conductors arranged closely in two
rows. In stiff fiber-reinforced composite, shear stress concentrations occur in
between neighboring fibers, and the electric field means shear stress in this
paper. Due to material failure of composites, there have been intensive studies
so far to estimate the field in between only a finite number of inclusions.
Indeed, fiber reinforced composites contain a large number of stiff fibers, and
the concentration can be strongly enhanced by some combination of inclusions.
Thus, we establish some asymptotes and optimal blow-up rates for the field in
narrow regions in between infinitely many conductors in two rows to describe
the horizontally and vertically combined effects of a large number of ones.
Especially, one of the blow-up rates is substantially different from the
existing result in the case of finite inclusions.
