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Optimized Circularly Polarized Patch Antenna with Horizontal and Side Slots for UHF RFID Readers
(2025-01-01)
Wichakoon, Worathan
;
Nuangwongsa, Kanawat
;
Phongcharoenpanich, Chuwong
This paper presents the design and optimization of a circularly polarized UHF RFID reader antenna. The initial radiator dimensions were set at 130 mm × 130 mm, and the feed position was fine-tuned, with simulations identifying x, y = 24.5, 24.5 mm as the optimal location for impedance matching. Further optimization focused on reducing the ground plane size, with a 170 mm × 170 mm ground plane providing the optimal balance, ensuring an axial ratio below 3 dB and stable |S| (dB) response across the 920-925 MHz frequency band. The final design demonstrated an improved radiation pattern and sufficient gain, making it an effective solution for UHF RFID reader applications.
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Broadband Two-Array Metasurface-Gridded MIMO Antenna with Dual-CP Bi-Directional Capabilities
(2025-01-01)
Supreeyatitikul, Nathapat
;
Kakhong, Khwanlada
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Prasong, Pusit
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Phongcharoenpanich, Chuwong
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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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Ultrawideband Circularly Polarized Cavity-Integrated EBG-Backed Archimedean Spiral Antenna for IoT Applications
(2025-01-01)
Luadang, Bancha
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Janpangngern, Pisit
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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
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Kuse, Ryuji
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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.
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Compact Broadband Circularly Polarized Metasurface Antenna with Split-Annular Slot Ground Structure
(2023-01-01)
Supreeyatitikul, Nathapat
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Chudpooti, Nonchanutt
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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
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Torrungrueng, Danai
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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.
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Circularly polarized reconfigurable microstrip loop antenna using parasitic patches and PIN diodes
(2020-07-01)
Kawdungta, Supakit
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Phongcharoenpanich, Chuwong
This research proposes a novel circularly polarized (CP) reconfigurable microstrip loop antenna for 2.4-2.5 GHz advanced wireless communication using two parasitic patches and two PIN diodes. The reconfigurable antenna can alternate between right hand circular polarization (RHCP) and left hand circular polarization (LHCP) at the main beam by manipulating the ON/OFF status of the PIN diodes. Simulations were carried out for the optimal antenna parameters, and an antenna prototype was fabricated and experiments were undertaken. The simulation and measured results are in good agreement. The antenna achieves an impedance bandwidth of 2.4-2.5 GHz and unidirectional radiation pattern with a maximum gain of 5 dBic and 3-dB axial ratio for both RHCP and LHCP. As a result, the proposed reconfigurable antenna could be utilized to improve wireless communication performance. In essence, the novelty of this research lies in the utilization of parasitic patches and shorted PIN diodes to transform linear to circular polarization; and the reconfigurability of polarization between RHCP and LHCP.
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Dual-band circularly polarized flat antenna with plano convex and concave slots for RFID readers
(2017-11-01)
Wongsakulphasatch, Prawate
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Phongcharoenpanich, Chuwong
This article has proposed a circularly polarized dual-band antenna with unidirectional pattern operating at the bandwidth frequencies of 920–925 MHz and 2.40–2.48 GHz for radiofrequency identification (RFID) readers. The proposed antenna structure is of a radiating patch with a single feeder and two pairs of plano convex and concave slots. This work has innovated and utilized the convex and concave slotting technique to generate the circular polarization. The simulated results showed that the dual-band antenna is of circular polarization (CP) and unidirectional radiation pattern with the 3 dB axial ratio and the respective gains of 1.31 and 1.36 dBic for the experimental lower and upper bandwidth frequencies. An antenna prototype was subsequently fabricated and tests performed. The simulated and measured results are in good agreement, rendering the proposed dual-band antenna with plano convex and concave slots suitably applicable to the ultrahigh frequency and microwave RFID readers.
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Single-fed broadband circularly polarized unidirectional antenna using folded plate with parasitic patch for universal UHF RFID readers
(2016-09-01)
Dentri, Sitthichai
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Phongcharoenpanich, Chuwong
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Kaemarungsi, Kamol
This research proposes a simple economical broadband circularly polarized antenna for universal ultra-high frequency (UHF) RF identification (RFID) readers. The antenna utilizes a folded plate, a two-corner truncated parasitic patch, and a ground plane. The folded plate, which is fabricated from one single plate, consists of a two-corner truncated main patch, a wall patch, and a feed line, where the main patch is perpendicular to the wall patch, which is in turn perpendicular to the feed line. The folded plate enables currents to flow with a phase difference. The simulation results achieved an |S<inf>11</inf>| < −15 dB of 805–966 MHz (18% bandwidth), a 3-dB axial ratio (AR) bandwidth of 834–962 MHz (14% AR bandwidth), and a gain higher than 8.6 dBic. The measured results obtained an |S<inf>11</inf>| < −15 dB of 806–970 MHz (18%), a 3-dB AR bandwidth of 816–963 MHz (16%), and a gain greater than 7.8 dBic. The proposed antenna is applicable for universal UHF RFID readers as it covers the entire operating UHF RFID frequency range of 840–960 MHz. The parametric study and evolution of the proposed antenna are detailed in this research paper as well. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:575–587, 2016.

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