A helix antenna structure includes loop antennas and a multilayered printed circuit board including printed circuit board layers. Each printed circuit board layer includes a peripheral loop antenna and each adjacent two loop antennas are electrically connected by a connection bridge functioning as a monopole antenna. A selected printed circuit board layer physically and electrically accommodates a transmitter inside ‘its’ peripheral loop antenna, and it further includes a first antenna feeding line which is connected to the loop antenna that is disposed on the selected printed circuit board layer and electrically connectable to a first output terminal of the transmitter. A second antenna feeding line is disposed on another printed circuit board layer and electrically connected to its loop antenna and connectable to another output terminal of the transmitter. The two antenna feeding lines lie in a plane perpendicular to an axis of the printed circuit board after its folding.