FIELD: measuring equipment.
SUBSTANCE: sensor contains the first and second interconnected autodine microwave generators, to which the first and second autodine signal selection units are respectively connected. And the first autodyne microwave generator is also connected to the first port of a three-port circulator, to the second port of which the first transceiving antenna is connected, the radiation pattern of which is directed to the first local area of control of the inner surface of the product, and the second transceiving antenna is connected to the third port. Its radiation pattern is directed to the second local area of control of the inner surface of the product, which is opposite the first local area.
EFFECT: improved measurement accuracy.