This thesis summarizes ongoing work to develop low-cost, wireless, resonant sensor array that can be used to monitor corrosion in infrastructure systems. A magnetically coupled sensor array is presented and analyzed using circuit model. The array acts as a magneto-inductive waveguide and the impedance discontinuities caused by corrosion (or other defects) lead to reflection. The relationship between the relative position of defects and pass band characteristics is investigated, providing a technique to determine the location of targets. A configuration for increased sensitivity and a method for defect localization are presented.