Reconstruction of Field Inside Dielectric Objects for Noninvasive SAR Measurement

Reconstruction of electromagnetic (EM) fields inside dielectric objects is studied. Such reconstruction methods have been developed mainly for noninvasive specific absorption rate (SAR) measurement. The methods enable us to measure the field inside the dielectric phantom illuminated by the device under test (DUT), without invasive insertion of the probe inside the phantom. In the proposed reconstruction method, EM currents on the surface of the dielectric object are reconstructed from field observed on the surface enclosing both the phantom and DUT. The fields inside the phantom are evaluated by the reconstructed currents. The validity and usefulness of the proposed method are demonstrated numerically and experimentally using a dielectric object located near a dipole antenna.