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Author: search.filters.author.Janpangngern, PisitSubject: search.filters.subject.circular polarization

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    Ultrawideband Circularly Polarized Cavity-Integrated EBG-Backed Archimedean Spiral Antenna for IoT Applications
    (2025-01-01)
    Luadang, Bancha
    ;
    Janpangngern, Pisit
    ;
    Phongcharoenpanich, Chuwong
    This paper presents a compact ultrawideband circularly polarized Archimedean spiral antenna integrating a cavity-backed structure with a circular EBG reflector. The hybrid design enhances gain, suppresses backward radiation, and improves directivity, particularly below 3.0 GHz. The antenna covers 1.5-9.0 GHz with |S11| ≤ -10 dB and axial ratio ≤ 3 dB. Simulations show peak gain over 11.96 dBic at 6.5 GHz and a front-to-back ratio improvement due to the cavity. The proposed structure is well-suited for GPS, Wi-Fi, and IoT applications.
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    Omnidirectional Circularly Polarized Monopole Antennas on Artificial Magnetic Conductor Ground Plane
    (2024-01-01)
    Janpangngern, Pisit
    ;
    Kuse, Ryuji
    ;
    Phongcharoenpanich, Chuwong
    ;
    Fukusako, Takeshi
    This research proposes omnidirectional circularly polarized monopole antennas (OCPA) with single-annular (SA-AMC) and dual-annular artificial magnetic conductor (DA-AMC) ground planes. The aim of the proposed antenna scheme is to circumvent the design rigidity of conventional OCPA whose inherent shortcoming is fixed bottom ground plane size. The OCPA with SA-AMC ground plane consists of a monopole element, four diagonally adjoined parasitic elements to convert linear to circular polarizations, and an SA-AMC ground plane. The OCPA with DA-AMC ground plane consists of a monopole element, four diagonally adjoined parasitic elements, and a DA-AMC ground plane. Unlike the conventional OCPA, the bottom ground plane radius (R-{text {g}}) of the OCPA with SA- and DA-AMC ground planes can be varied between 18.4 - 188.4 mm; and 29.2 - 119.2 mm, respectively, without affecting the omnidirectionality and impedance and axial ratio (AR) bandwidths of the OCPA. Furthermore, the SA- and DA-AMC ground planes effectively improve the impedance (left |{{S-{11}}}right | leq -,10 dB) and AR bandwidths (AR leq 3,{} dB) while reducing leakage current on the coaxial feeder cable. The measured left |{{S-{11}}}right | and AR bandwidths of the OCPA with SA-AMC ground plane, given the optimal R-{g} of 18.4 mm, are 8.08% (5.34 - 5.79 GHz) and 4.38% (5.36 - 5.60 GHz), while those of the OCPA with DA-AMC ground plane, given the optimal R-{text {g}} of 29.2 mm, are 14.37% (5.10 - 5.89 GHz) and 19.85% (4.90 - 5.98 GHz). The novelty of this research lies in the use of SA- and DA-AMC structures to circumvent the design rigidity of the conventional OCPA. Essentially, the integration of the AMC structures offers design flexibility in the realization of OCPA.