a sensor system for determining deformation of an object subject to forces . the sensor system comprises an object upon which forces are exerted and a cavity within the object , a first substrate for supporting surface acoustic waves in an upper surface of the first substrate , the first substrate disposed in the cavity , a first surface acoustic wave transducer disposed on the upper surface and responsive to an interrogation signal for generating an incident surface acoustic wave in the upper surface , a first reflector array responsive to the incident surface acoustic wave for creating reflected surface acoustic waves on the upper surface , the reflected surface acoustic waves received by the transducer and having characteristics indicative of strain deformation of the object due to a force exerted on the object .