Microwave interferometric method for metal sheet thickness measurement

A new microwave method capable of contactless thickness measurement of metal sheets with high resolution has been proposed. First experimental results in X-band are reported. The method is based on precise interferometric phase evaluation of a signal reflected step by step from two surfaces of a metal sheet whose thickness is to be measured. This is achieved using interference between the reflected and reference signals. Micrometer resolution at 10 GHz can be expected.