Multi-relaxation generalized refractive mixing dielectric model of moist soils

In this paper, a multi-relaxation generalized refractive mixing dielectric model (GRMDM) for moist soil is proposed and substantiated in the frequency range from 0.03 to 26.5 GHz. This model is based on the GRMDM of [1] developed in the range of GHz frequencies, considering only the dipole relaxation of water in the soil. The error of this model was shown to noticeably increase with the transition to the MHz range. Because in this range, one more relaxation, that is, ionic (Maxwell-Wagner) relaxation largely affects on the complex dielectric constant. The multi-frequency relaxation GRMDM developed in this paper compensates for this disadvantage of the single-relaxation GRMDM. In this model, the two-frequency relaxation Debye equation for the dielectric spectra of bound water has been used, thus expanding the scope of the GRMDM to the MHz range. The main advantage of this model is that it predicts complex dielectric constant of moist soils simultaneously in the GHz and MHz ranges.