Wireless powering of sensors embedded in concrete

Two kinds of electrical models for concrete have been used to calculate the transmission loss, propagation loss and total loss of normal incidence and oblique incidence of wave. The value of these losses depends on the electrical properties of the concrete, frequency of wave and the incidence angle. When the wave is normal incident and the frequency is between 20-80 MHz, the sensor will receive significantly larger power than the other cases we examined. Also, an optimum frequency range (corresponding to minimum transmission losses) has been identified for the cases we have examined. Detailed comparison between powering techniques that use RF signals versus low frequency inductive coupling will be presented at the conference. Also, the effects of rebars will be considered.