Evaluation of an electric field sensor for nondestructive material inspection

An electric field sensor is fabricated on a 125 micron thick flexible dielectric substrate for electromagnetic (EM) nondestructive material inspection at 915 MHz. The sensor consists of an electrically short dipole antenna and a radio frequency (RF) diode detector connected to a pair of high impedance screen printed carbon lines. The DC component of the rectified diode voltage conveyed across the high impedance lines is measured using a data acquisition circuit. Sensor measurements are validated with simulated data for a conformal patch antenna operating at 915 MHz. Sensor performance for EM nondestructive testing (NDT) is evaluated using phantom defects in low loss dielectric slabs. Preliminary results indicate sensor utility for EM NDT and support further testing on realistic defects.