FDTD ANALYSIS OF 2-DIMENSIONAL CAVITY-BACKED ANTENNA FOR SUBSURFACE RADAR

The antennas for subsurface radar are usually covered with a conductin g cavity to prevent the radiation field from affecting the electromagn etic environment and to protect the received field from external noise s. Furthermore, radiowave absorber is attached to the interior wall of the cavity in order to suppress the multiple reflections in the cavit y. In this paper, the characteristics of the two-dimensional cavity-ba cked antenna having the absorber and the over-all properties of this s ubsurface radar due to buried objects are numerically analyzed by the Finite-Difference Time-Domain method. It is shown that the pulse propa gation in the ground is confined to the narrow region due to the cavit y. It is also shown that the multiple reflections in the cavity are ef fectively suppressed by choosing the suitable absorber, and so that th e distinctive pulse echo can be obtained.