Wideband Circularly Polarized Antenna With Novel Asymmetric Y-Shaped Arms
Rui Wu, Jian‐Hong Lin, Jian‐Feng Li, Fu‐Chang Chen
Abstract
A wideband circularly polarized antenna with novel asymmetric Y-shaped parasitic arms is proposed. The antenna consists of Y-shaped feedlines with vacant-quarter rings, asymmetric Y-shaped parasitic arms, rectangular patches, and a reflector. The circularly polarized radiation is generated by exciting the Y-shaped feedlines with vacant-quarter rings. The impedance matching bandwidth (IBW) and axial ratio bandwidth (ARBW) are effectively improved by introducing asymmetric Y-shaped parasitic arms, and four CP modes are introduced in the operating band. The overall dimension <strike xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</strike> of the proposed antenna are 0.84λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.84λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.27λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> (λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength of the center frequency in the free space), with a simple structure. The measured results show that the wide IBW covers 1.2–3.0 GHz (86%), and the ARBW is 1.3–3.2 GHz (84%). Moreover, 79% of the overlap bandwidth (1.32–3.0 GHz) is achieved between IBW and ARBW, and the measured cross-polarization discrimination is more than 18 dBic on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Z</i> -axis. The antenna can be used in wireless communication due to the characteristics of wide impedance bandwidth and axial ratio bandwidth.