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Author: search.filters.author.Supreeyatitikul, NathapatSubject: search.filters.subject.circular polarization

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    Broadband Two-Array Metasurface-Gridded MIMO Antenna with Dual-CP Bi-Directional Capabilities
    (2025-01-01)
    Supreeyatitikul, Nathapat
    ;
    Kakhong, Khwanlada
    ;
    Prasong, Pusit
    ;
    Phongcharoenpanich, Chuwong
    ;
    Konpang, Jessada
    This study presents a novel two-array MTS-gridded MIMO antenna with dual circular polarization (CP) bidirectional capabilities for full-duplex communications. The proposed antenna consists of two mirrored clusters, each comprising a single-element antenna formed by a 3 × 4 MTS-gridded element array, a circular patch, and a ground plane. The antenna demonstrates a wide measured return loss bandwidth (RLBW) of 56.46% (5 - 8.67 GHz), axial ratio bandwidth (ARBW) of 18.15% (6.26 - 7.44 GHz), and strong isolation below -22 dB. Peak gains of 6.5 dBic and 6.55 dBic were observed at 6.6 GHz and 6.54 GHz for Ports 1 and 2, respectively. Furthermore, the low envelope correlation coefficient (< 0.005) and high diversity gain (> 9.985 dB) validate its effectiveness for multi-port applications. The bidirectional radiation pattern and dual circular polarization support simultaneous transmission and reception, making the design well-suited for full-duplex MIMO operation.
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    Compact Broadband Circularly Polarized Metasurface Antenna with Split-Annular Slot Ground Structure
    (2023-01-01)
    Supreeyatitikul, Nathapat
    ;
    Chudpooti, Nonchanutt
    ;
    Phongcharoenpanich, Chuwong
    This paper presents a broadband CP MTS-inspired antenna with split-annular slot ground structure. The CP radiation and antenna configuration are deployed characteristic mode analysis (CMA). The proposed CP MTS-inspired antenna with split-annular slot ground structure comprised of upper substrate and lower substrate. The upper substrate consisted of 5× 5 uniformly MTS unit cells, and the split-annular slot ground plane and microstrip feed line are included on the lower substrate. In CMA results, the 5× 5 MTS-inspired unit cells generated CP radiation by Modes 1 and 2. Besides, the split-annular slot ground structure can be produced two orthogonal electric fields at the center frequency of 5 GHz by Modes 3 and 5 for excitation source. This proposed antenna achieved simulated IBW of 59.4% (3.57 - 6.55 GHz), and simulated ARBW of 24.22% (4.43 - 5.64 GHz). The maximum gain at 4.7 GHz is 5.72 dBic, which has RHCP characteristic radiation. The proposed antenna is appropriate functionally for C-band wireless applications.
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    Quadri-Cluster Broadband Circularly-Polarized Sequentially-Rotated Metasurface-Based Antenna Array for C-Band Satellite Communications
    (2021-01-01)
    Supreeyatitikul, Nathapat
    ;
    Torrungrueng, Danai
    ;
    Phongcharoenpanich, Chuwong
    This research proposes a compact quadri-cluster broadband circularly polarized (CP) sequentially-rotated metasurface-based (MTS) antenna array for the C-band frequency spectrum. One cluster of the quadri-cluster MTS-based antenna array consisted of 4 times 4 S-shaped periodically-arranged MTS elements. The sequentially-rotated feed network was utilized to realize circular polarization and improve the impedance bandwidth (IBW), 3-dB axial ratio bandwidth (ARBW) and 3-dB boresight gain bandwidth of the quadri-cluster MTS-based antenna array. Simulations were performed and results were compared with experiments. The measured IBW and ARBW were 84.74% (4.0-9.0 GHz) and 57.6% (4.2-7.6 GHz) at the center frequency of 5.9 GHz, rendering the proposed quadri-cluster MTS-based antenna array suitable for satellite communication applications. In addition, the quadri-cluster MTS-based antenna array achieved the measured 3-dB boresight gain bandwidth of 81.3% (3.9-8.7 GHz), the maximum gain of 10.04 dBic at 5.6 GHz, and low radar cross-section. Specifically, the novelty of this research lies in the use of the sequentially-rotated feed network with the S-shaped MTS elements to effectively enhance ARBW of the quadri-cluster MTS-based antenna array for the C-band frequency spectrum.