Bow-tie-Shaped Rotated Yagi Antenna with Dual Circular Polarization for IoT Applications

This paper proposes a bow-tie-shaped rotated stacked Yagi antenna with dual-circular polarization (CP). The proposed antenna consists of four elements with different angle: a director, a reflector, and two orthogonal driven elements, and all antenna elements are designed in a bow-tie-shape. The two driven elements connected with LC balun. Each stacked element, except for the two driven elements, is equally rotated at an angle of 45
^◦
based on the driven elements, resulting in the proposed antenna having dual-circular polarizations. A driven element located at the top of substrate forms right-hand circular polarization (RHCP), while the other forms left-hand circular polarization (LHCP). The antenna size is 0.39λ
0
× 0.39λ
0
× 0.27λ
0
at 2.45 GHz. The simulated -10dB bandwidth, 3 dB axial ratio (AR) bandwidth and maximum gain of RHCP and LHCP are 6.2% / 5.3% and 3.1% / 2.6%, and 4.6 dBic / 4.4 dBic, respectively.