Preliminary Electromagnetic Simulations of Radar Scattering from the Lunar Surface as Applied to Mini-rf Observations

Introduction: Bistatic radar measurements of the lunar surface are being carried out by the Mini-RF team using Arecibo as a transmitter, cf. Fig. 1. The resulting radar images – the first to be collected at non-zero bistatic phase angle β (between source and receiver) – are being studied extensively to test the hypothesis that water ice resides inside permanently shadowed and perhaps other very cold regions near the lunar poles. The present work uses electromagnetic simulations to model radar scattering from a Mini-RF lunar " pixel " (on the order of 20 m x 20 m) at wavelength 12.6 cm. We focus on understanding in high detail how properties of the far-field scattered radiation observed by Mini-RF changes with bistatic phase angle, surface roughness, and a plausible variety of inhomogeneous compositions, incl. buried or blocky water ice.