A annular recuperator to recover waste heat from a gas turbine exhaust in order to preheat the compressed air delivered to the gas turbine combustor, formed with gas flow passages for the relatively hot turbine exhaust gases and air flow passages for the relatively cool compressed air separated by thin, thermally conductive metal foil barriers. The flow passages have contoured gaps between the foil surfaces in order to establish the desired air/gas aerodynamic friction induced pressure drop and mass flow profiles within the recuperator core. The gaps are set by an array of dimples in the metal foil barriers with each dimple having a precisely controlled height. The metal foil barriers are formed by first dimpling and then bending a single sheet metal strip to form a convoluted foil structure that is wrapped around an inner cylinder and the ends joined. An outer cylinder is then installed around the wrapped, convoluted foil barrier structure. The ends of the foil strips are welded closed and the turbine exhaust gas flow passages are left open at the ends. The inlet and outlet ports for the compressed air are formed in the opposite ends of the inner cylinder to face radially and the turbine exhaust gases enter and exit axially at the opposite ends of the core.
 The U.S. Government has a paid-up license in this invention and the right in limited circumstances to require the patent owner to license others on reasonable terms as provided for by the terms of the Advanced MicroTurbine System Contract NO. DE-FC02-01CH11058 awarded by the Department of Energy.