Near­field diffraction pattern by an underground void of circular cylinder

Abstract

Amplitude patterns of the electromagnetic field scattered by a circular air cylinder embedded in a dielectric medium are analyzed. Twenty five decibel double dip patterns measured by the scale­down experiment are presented. Theoretical analysis shows that these double dips become double nulls in the near­field region. This phenomenon is useful in locating high­contrast geological anomalies. Copyright ？ 1989 Wiley Periodicals, Inc., A Wiley Company