Direct-path mitigation for underground imaging in RF Tomography

Belowground imaging using RF Tomography is challenged by strong direct-path coupling between sensors. In this work, a direct-path mitigation procedure is introduced, consisting of two steps. First, the Tx and Rx dipoles are rotated in along particular directions that maximizes the signal with respect to the direct-path contribution. Then, the remaining contribution is removed by using a hybrid analog/digital feedback loop at the receiver side.