An ablation catheter apparatus with a monopole antenna that is arranged to
provide a relatively uniform electric field and a method for using such
an ablation catheter apparatus are disclosed. According to one aspect of
the present invention, an ablation catheter includes an elongated
flexible tubular member that is adapted to be inserted into the body of a
patient, and a transmission line that is disposed within the tubular
member. The transmission line has a distal end and a proximal end which
is arranged to be connected to an electromagnetic energy source. The
catheter also includes a monopole antenna with tip section and a body
section that includes a distal end and a proximal end. The tip section
and the body section are arranged to produce a relatively uniform
electric field around the monopole antenna which is sufficiently strong
to cause tissue ablation. The proximal end of the body section of the
monopole antenna is arranged to be electrically coupled to the
transmission line.