  In this paper, we consider capacity degradations stemming from potential
hardware impairments (HWI) of newly proposed Large Intelligent Surface (LIS)
systems. Without HWI, the utility of surface-area (the first-order derivative
of the capacity with respect to surface-area) is shown to be proportional to
the inverse of it. With HWI, the capacity as well as the utility of
surface-area are both degraded, due to a higher effective noise level caused by
the HWI. After first modeling the HWI in a general form, we derive the
effective noise density and the decrement of utility in closed-forms. With
those the impacts of increasing the surface-area can be clearly seen. One
interesting but also natural outcome is that both the capacity and utility can
be decreased when increasing the surface-area in the cases with severe HWI. The
turning points where the capacity and the utility start to decrease with HWI
can be evaluated from the derived formulas for them. Further, we also consider
distributed implementations of a LIS system by splitting it into multiple small
LIS-Units, where the impacts of HWI can be significantly suppressed due to a
smaller surface-area of each unit.
