  In this letter, we study the performance of a wireless power transfer system
under energy harvesting distribution uncertainty. The uncertainty captures
practical nonidealities of the rectification process and is modelled as the
maximum Kullback-Leibler distance of the actual distribution from a nominal
distribution. The case where symmetrized divergence is considered for the
statistical distance between distributions is also considered. By formulating a
convex optimization problem, we investigate a mathematical framework that
provides closed form expressions for the minimum average harvested energy (the
worst performance) and the associated statistical distribution. Theoretical
results show that the energy harvesting performance is significantly degraded
as the level of the uncertainty increases.
