A planer antenna includes first and second planer helical antennas and a
ground pattern. The first planer helical antenna has a first axial
orientation and includes first and second helical conductive patterns on
first and second surfaces of a supporting substrate. The second planer
helical antenna has a second axial orientation and includes the first and
second helical conductive patterns on the first and second surfaces of
the supporting substrate. The ground pattern is on the second surface of
the supporting substrate and provides a ground connection for the first
and second planer helical antennas. The ground pattern is approximately
centered at an intersection of the first and second axial orientations
and the first and second planer helical antennas are off-center of the
intersection of the first and second axial orientations.