HFSS modeling of cross-coupling in borehole radar

摘要

The total cross-coupling between UWB borehole radar antenna slots in a metal drill string were modelled using High Frequency Structure Simulator (HFSS). Methods of suppressing this coupling were also modelled and provided promising results. Ferrite sleeves were able to provide a 30dB reduction of cross-coupling levels, and phased pairs of transmit slots provided a reduction of 20dB. Both methods achieved poorer performance when the drill string was non-concentric in the borehole however.