Planar Endfire Circularly Polarized Antenna Using Combined Magnetic Dipoles

Abstract

A novel planar circularly polarized antenna with endfire radiation beam in parallel with the antenna substrate's plane is proposed. The operation principle of the antenna is analyzed and design guidelines are laid down. Then, an optimized loop-aperture combined antenna is designed and demonstrated to exhibit an endfire beam in parallel with its plane within 5.74-5.88 GHz for |S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | lower than -10 dB and axial ratio smaller than 3 dB. The proposed antenna can be used as a low-profile, cost-effective, hand-held reader antenna for radio frequency identification systems .