Controller Design for Unstable Distributed Plants

In this paper we solve the H
_∞
mixed sensitivity minimization problem for a class of unstable distributed systems. The solution is based on an extension of the skew Toeplits methodology developed in [1], [3], [4], [6], [10]. The key mathematical fact used is that the skew Toeplits operators arising in the unstable case are finite rank perturbations of the classical skew Toeplits operators obtained from compressions of rational functions.