Patent ID: 9217809
Filing Date: 2015-12-22
Classification: G01R,G01V,H01Q

Abstract:
1. An antenna ( 3 ) of an electromagnetic probe used in investigation of geological formations (GF) surrounding a borehole (WBH) comprising a conductive base ( 31 ) and an antenna element ( 32 ), the conductive base ( 31 ) comprising an opened non-resonant cavity ( 33 ), the antenna element ( 32 ) being embedded in the cavity ( 33 ) and going right through the cavity, the antenna element ( 32 ) being isolated from the conductive base ( 31 ), the antenna element ( 32 ) being coupled to at least one electronic module via a first ( 34 A) and a second ( 34 B) port, respectively, the electronic module configured to apply a current distribution to the antenna element via one or more of the first and second ports, such that the antenna is operated in a substantially pure magnetic dipole when the current distribution is applied to the antenna such that current increases from a first end of the antenna to a middle portion of the antenna, and then decreases from the middle portion of the antenna to a second end of the antenna, and a substantially pure electric dipole when the current distribution is applied to the antenna such that current increases from the first end of the antenna to the second end of the antenna.