Effectiveness of a dipole feeder for the cross spiral antenna which is a circularly and linearly polarized planar antenna

摘要

A novel feeding way tor balanced antennas, loop antennas and spiral antennas, is presented. The author invented recently a circularly polarized simple loop/spiral antenna (CSA), which is configured only by twisting a loop like a cross shape. The CSA can radiate good circular polarization (CP), if it is fed by a good balanced feeder. The strict balance of currents is needed that CSA radiates good CP waves, so a feeder that can neutralize unbalanced currents of a poor balanced feeder is necessary. In this paper, a dipole element is employed to feed CSA. To show the effectiveness of the dipole feeder, the S11 characteristics and radiation patters obtained by feeding CSA with a coaxial cable are compared with those obtained by feeding CSA with a balanced feeder. These results show that the dipole feeder is useful to neutralize unbalanced currents.