Narrow Angle Range Radiation Control Scheme for Reflected Wave Reduction in Wirelessly Powered Structural Health Monitoring

A microwave beam radiation control scheme is described for an on-vehicle vision-sensing microwave power transfer system to provide sufficient power supply while curtailing reflected wave spreads. Multiple receive antennas are mounted with a narrow interval on an inner side wall of a tunnel. These Rx antenna targets can be observed from the vehicle moving at high speed as sequentially passing targets with a short time interval. These targets are detected and tracked within a narrow angle range centered at the direction of the maximum achievable power transfer efficiency. By limiting the microwave incidence angle to near the vertical direction, microwave absorbers installed around the targets are expected to maximally reduce interference to existing wireless systems in adjacent frequency bands. Simulation results demonstrated that our proposed scheme achieved a larger amount of wirelessly transferred energy than a conventional wide-angle beam tracking scheme for a single target and that the radio field strengths were dramatically decreased in the surrounding area of the power supply spot.