Novel Chirp Pulse Transmission Imaging Approach for Average Permittivity Estimation and Mapping

Chirp pulse microwave computed tomography (CP-MCT) has been proposed as a robust mathematical technique for reconstructing images of the interior of objects. However, its application has been primarily limited to reconstructing attenuation images in simple scenarios. In this paper, chirp pulse transmission imaging (CPTI) is introduced to leverage signal isolation capabilities of microwave time delay spectroscopy (MTDS) and identify direct-path signals for accurate permittivity estimation. The approach has been validated through various simulation scenarios, including homogeneous slabs with varying permittivities, a slab with an inclusion, and homogeneous cylinders. The proposed method demonstrates high accuracy in determining the time of arrival (TOA), resulting in reliable average permittivity measurements and improved accuracy when compared with other methods such as peak detection. Subsequently, the backprojected images produced by the method provide a clear and accurate representation of the object’s permittivity.