Have you ever wondered what type of antenna vendors put on an implantable device? The image on the right is an implantable
designed by Cynthia Furse of
the University of Utah. Pretty cool.

UPDATE: Dr Furse was kind enough to reply to my inquiry to say that the
image represents the current density on a spiral microstrip patch
antenna. She also included a paper she wrote on antenna design for
pacemaker communications. Thanks!