Frequency Doubling Antenna Sensor For Wireless Strain And Crack Sensing

Abstract

A strain and crack sensor senses an amount of strain induced in an object. A receiving planar antenna has a first resonant frequency and is configured to receive a querying signal at the first resonant frequency. A transmitting planar antenna has a second resonant frequency that is twice the first resonant frequency. At least one of the receiving planar antenna and the transmitting planar antenna is bonded to the object so that at least one of strain induced in the object or a crack formed in the object causes a shift in at least one of the first resonant frequency or the second resonant frequency. A matching element is in electrical communication with the first planar antenna and the second planar antenna. The matching element is configured to cause the transmitting planar antenna to radiate a response signal in response to the querying signal.