A dipole feeder for circularly and linearly polarized cross shape loop/spiral antennas

Abstract

A novel feeding way for balanced feed antennas is presented. To construct the balanced feed antenna, a cross shape loop/spiral antenna (CSA)—a CP antenna invented by the author—needs to be fed through a well-balanced port. A poor current balance will bring a serious deterioration in CP radiation. In addition, the current balance of general ports is not adequate. For these reasons, a feeder reducing the influence of an unbalanced current should be suggested. In this paper, a dipole is employed as a feeder for CSA. S₁₁ characteristics and CP radiation patterns obtained by being fed through a coaxial cable (an unbalanced feed) are compared with those obtained by being fed through a balanced port to discuss the effectiveness of the dipole feeder.