On the use of the source reconstruction method to estimate incident field distributions in microwave imaging

Microwave Imaging (MWI) is a modality that attempts to obtain the dielectric profile of an object of interest (OI) by exposing it to successive interrogation from a number of co-resident antennas. MWI is advantageous because it is noninvasive and non-ionizing, and consequently it is being used in areas such as biomedical imaging and industrial non-destructive testing. The performance of MWI is dependent, in part, on accurate knowledge of the incident field used to interrogate the OI. The antennas used in MWI systems are usually approximated by simple models, such as point sources, in order to reduce the cost of the numerical model (M. Ostadrahimi et. al., IEEE Antennas Wireless Propag. Lett., 10, 900–903, 2011). This results in the incident field being approximated, and thus, calibration techniques are necessary to compensate for the modelling error. This can lead to degraded reconstructed image quality or additional time consuming measurements needed for calibration.