InSAR coherence due to remote sensing of low-loss, guiding planar-layered geophysical media using H-polarized microwaves

We propose a planar-layered medium-based radar backscatter model to predict coherence trends, in Interferometric Synthetic Aperture Radar (InSAR) images, manifest when interrogating planar-layered dielectric geophysical subsurfaces. This InSAR coherence model improves upon past ones in two ways: Incorporation of “multi-bounce”, arising from the guidance behavior of minimally-attenuating and high-contrast dielectric slabs, as well as azimuthal deviation in antenna pointing. Including the former renders this model especially suitable for analyzing coherence modifications (decorrelation and phase bias) arising from remote sensing of low-attenuating targets (e.g., dry soil), which augments applicability to high-attenuating targets (e.g., wet, salty soils) readily analyzed with many traditional InSAR models. Representing the model´s key contributions, we discuss two predicted trends: Namely, in the limit of a perfectly guiding dielectric slab (i.e., zero attenuation and infinite dielectric contrast), the interferometric correlation is inversely proportional to the InSAR perpendicular baseline length and the phase bias linearly diverges.