A radio guidance antenna in which the sum of mutual inductances of
antennas is minimized. The radio guidance antenna includes a first
antenna which is divided into upper and lower half regions by antenna
conductors, and a second antenna which is composed of an antenna
conductor and formed on the same plane as or a plane parallel to a plane
of the first antenna. The second antenna is not connected to the first
antenna at any points where it intersects the first antenna, but rather
is inductively coupled to the upper and lower halves of the first antenna
through mutual inductance regions. The first antenna is supplied with
electric power from a first feeding point, and the second antenna is
supplied with electric power from a second feeding point. The invention
also includes a data communication method and a non-contact data
communication apparatus which make use of the radio guidance antenna.