An assembly includes a particulate matter (PM) filter that comprises an upstream end for receiving exhaust gas, a downstream end and multiple zones. An absorbing layer absorbs microwave energy in one of N frequency ranges and is arranged with the upstream end. N is an integer. A frequency selective filter has M frequency selective segments and receives microwave energy in the N frequency ranges. M is an integer. One of the M frequency selective segments permits passage of the microwave energy in one of the N frequency ranges and does not permit passage of microwave energy in the other of the N frequency ranges.
STATEMENT OF GOVERNMENT RIGHTS
This disclosure was produced pursuant to U.S. Government Contract No. DE-FC-04-03 AL67635 with the Department of Energy (DoE). The U.S. Government has certain rights in this disclosure.