A problem of practical importance is to find a linear controller that
shapes the closed loop frequency responses in some desirable fashion.
When the magnitude of the target shapes is specified, this problem may
be cast as that of finding a controller such that several H-infinity,
norms satisfy specified bounds. In this paper we show that, under sui
table assumptions, an exact solution to this multiobjective H-infinity
problem can be obtained. The method we propose requires the solution
to. (1) a finite-dimensional linear matrix inequality problem, and (2)
a standard single objective H-infinity problem for a suitably constru
cted auxiliary plant. We illustrate the results with a numerical examp
le.