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EBG-backed ultrawideband circularly polarized Archimedean spiral antenna scheme for IoT applications
(2025-12-01)
Luadang, Bancha
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Ainthachot, Chalanthon
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Janpangngern, Pisit
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Pookkapund, Khanet
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Torrungrueng, Danai
This research proposes a low-profile ultrawideband circularly polarized Archimedean spiral antenna with an electromagnetic band gap (EBG)-backed structure. The proposed antenna scheme consists of an upper-layer spiral radiator, a microstrip tapered balun, and a lower-layer high-impedance circular EBG reflector of three concentric rings of trapezoid-shaped unit cells. The antenna scheme can achieve a significant profile reduction, with a total height of 0.1 wavelengths at the lowest operational frequency. The integration of the EBG reflector improves the radiation characteristics and antenna gain, achieving a maximum gain of 9.87 dBic at 6.90 GHz. The EBG reflector also improves impedance matching and axial ratio (AR) over the 1.5–8.75 GHz frequency range, achieving a wide AR bandwidth of 141.46%. The novelty of this work lies in the integration of Archimedean spiral antenna with high-impedance EBG reflector of trapezoid-shaped unit cells to enhance the impedance and AR bandwidths without increasing the overall antenna profile. Essentially, the proposed antenna scheme is suitable for broadband communication systems that require ultrawide bandwidth, circular polarization, and a small form factor.
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Broadband unidirectional twin-element MIMO antenna scheme for mid-band 5G and WLAN laptops
(2024-12-01)
Luadang, Bancha
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Janpangngern, Pisit
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Pookkapund, Khanet
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Dentri, Sitthichai
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Krairiksh, Monai
This research proposes a broadband unidirectional twin-element multiple-input-multiple-output (MIMO) antenna scheme for mid-band 5G and WLAN applications. The twin-element antenna scheme comprises two single-element antennas, and each single-element antenna consists of a T-shaped hemispherical feeding patch, left- and right-arm radiating patches, and a conjoined triangular ground plane. The twin-element MIMO antenna scheme is integrated with a laptop model functioning as the reflector. The measured impedance bandwidth (|S<inf>11</inf>|, |S<inf>22</inf>|≤ − 6 dB) are 55.32%, covering 3.4–6.0 GHz, and the measured mutual coupling (|S<inf>12</inf>|) is less than − 15 dB. The measured gain at the center frequency (4.5 GHz) is 4.585 dBi. Besides, the measured xz- and yz-plane cross-polarization levels are below − 25 dB and − 15 dB, respectively. The half-power beamwidth (HPBW) in the xz-plane at 3.5, 4.5, and 5.5 GHz are 99°, 92.8°, and 84.2°, and the corresponding HPBW in the yz-plane are 102°, 78°, and 102°. The measured xz- and yz-plane back lobe levels are below − 15 dB across the entire operating frequency band (3.5–5.5 GHz). The radiation pattern of the twin-element MIMO antenna scheme is of unidirectionality. Furthermore, the envelope correlation coefficient and diversity gain of the twin-element antenna scheme are < 0.001 and > 9.99 dB, respectively. The proposed broadband unidirectional twin-element MIMO antenna scheme is thus operationally suitable for mid-band 5G/WLAN communication systems. Essentially, this research is the first to propose a broadband twin-element MIMO antenna scheme for mid-band 5G/WLAN applications.
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Pragmatic Design of a Rectangular Printed Dipole Array Antenna for 5G Base Station
(2024-01-01)
Pookkapund, Khanet
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Pukraksa, Rerkchai
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Dentri, Sitthichai
This paper presents the design, fabrication and measurement of a rectangular printed dipole array antenna for 5G base stations. The antenna element is composed of a rectangular printed dipole featuring a U-shaped gap and slot positioned atop a square reflector. The measured results of the prototype antenna exhibit good agreement with simulations. The impedance bandwidth of the antenna is noteworthy, covering a substantial frequency range of 3.00 GHz - 3.82 GHz, yielding a bandwidth of 23%. The maximum gains are 6.49 dBi at a frequency of 3.5 GHz. The half-power beamwidths (HPBW) in the x-z and y-z planes are obtained to be 101.45° and 22.44°, respectively, at the frequency of 3.5 GHz. These results underscore the effectiveness of the designed rectangular printed dipole array antenna, showcasing its suitability for 5G base station applications.
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Portable Wideband Directional Antenna Scheme with Semicircular Corrugated Reflector for Digital Television Reception
(2022-07-01)
Luadang, Bancha
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Pukraksa, Rerkchai
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Janpangngern, Pisit
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Pookkapund, Khanet
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Dentri, Sitthichai
This research proposed a portable wideband horizontally-polarized directional antenna scheme with a radome for digital terrestrial television reception. The operating frequency band of the proposed antenna scheme is 470–890 MHz. The portable antenna scheme was an adaptation of the Yagi-Uda antenna, consisting of a folded bowtie radiator, a semicircular corrugated reflector, and a V-shaped director. Simulations were carried out, and an antenna prototype was fabricated. To validate, experiments were undertaken to assess the antenna performance, including the impedance bandwidth (|S<inf>11</inf>| ≤ −10 dB), gain, and unidirectionality. The measured impedance bandwidth was 75.93%, covering 424–943 MHz, with a measured antenna gain of 2.69–4.84 dBi. The radiation pattern was of unidirectionality for the entire operating frequency band. The measured xz- and yz-plane half-power beamwidths were 150°, 159°, 160° and 102°, 78°, 102° at 470, 680, and 890 MHz, with the corresponding cross-polarization below −20 dB and −40 dB. The radome had a negligible impact on the impedance bandwidth, gain, and radiation pattern. The power obtained for the outdoor test, at 514 MHz, was 38.4 dBµV (−70.4 dBm) with a carrier-to-noise ratio (C/N) of 11.6 dB. In addition, the power obtained for the indoor test was 26.6 dBµV (−82.2 dBm) with a C/N of 10.9 dB. The novelty of this research lies in the concurrent use of the Yagi-Uda and bowtie antenna technologies to improve the impedance bandwidth and directionality of the antenna for digital terrestrial television reception.
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Single-fed broadband CP bidirectional antenna with double-layer diagonally aligned plates for universal UHF-RFID applications
(2020-01-01)
Dentri, Sitthichai
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Pookkapund, Khanet
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Luadang, Bancha
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Akkaraekthalin, Prayoot
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Phongcharoenpanich, Chuwong
This research proposes a single-fed broadband circularly polarized (CP) bidirectional antenna operable in 840-960 MHz frequency band for readers of universal UHF-RFID applications. The proposed antenna is comprised of upper-layer conductor, lower-layer conductor, and wall patches. The upper-layer conductor consists of two diagonally aligned rectangular copper plates with a feeding gap at the center, and the lower-layer conductor is of two diagonally adjoined rectangular plates. The upper- and lower-layer conductors are adjoined with the wall patches. The diagonal alignment technique of the upper- and lower-layer plates was used to realize circular polarization and improve 3-dB axial ratio (AR) bandwidth. The double layers were deployed to improve impedance bandwidth (|S11| < -10 dB) and achieve bidirectional radiation pattern. The simulated impedance bandwidth and 3-dB AR bandwidth were 772.19-1014.6 MHz (27.13%) and 675-1000 MHz (38.80%), and the corresponding measured results were 759-1011 MHz (28.47%) and 648-1110 MHz (52.55%). The simulated LHCP/RHCP half-power beamwidth (HPBW), 3-dB AR beamwidth, and gain were 56° - 90°/54° - 92°, 60° - 104°, and 4.94 - 5.89 dBic, while the corresponding measured results were 52° - 98°/62° - 97°, 96° - 126°, and 4.28 - 5.72 dBic. As a result, the single-fed broadband CP bidirectional antenna is applicable to universal UHF-RFID readers. Besides, the novelty of this research lies in the use of diagonal alignment of conducting plates to achieve circular polarization and wider AR bandwidth.
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Broadband circularly polarized microstrip patch antenna using circular artificial ground structure and meandering probe
(2020-01-01)
Pookkapund, Khanet
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Sakonkanapong, Arnon
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Kuse, Ryuji
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Phongcharoenpanich, Chuwong
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Fukusako, Takeshi
To enhance axial ratio (AR) bandwidth, this research proposes a circularly polarized (CP) single-fed microstrip patch antenna using a circular artificial ground structure (AGS) and meandering probe. To achieve broader AR bandwidth, the circular AGS is populated with rectangular unit cells and partially cut unit cells along the circular contour, while the meandering probe is used to improve the impedance bandwidth. Simulations are performed and results compared with that of conventional rectangular-AGS antenna. The simulation results show that the circular-AGS antenna, given 62 mm circular ground plane, achieves broader impedance (5.12 - 9.00 GHz and 54%), AR (5.21 - 8.27 GHz and 45%) and gain bandwidths (3.85 - 7.00 GHz and 58.06%), in comparison with the rectangular-AGS antenna (4.50 - 7.45 GHz and 49%; 4.52 - 7.42 GHz and 21%; and 4.00 - 6.80 GHz and 51.58% for impedance, AR and gain bandwidths). The circular-AGS antenna is capable of converting linear polarization in the off-axial ratio band into circular polarization. To verify, a circular-AGS antenna prototype is fabricated and experiments undertaken. The experimental impedance, AR and gain bandwidths of the circular-AGS antenna are 47.82% (5.17 - 8.42 GHz), 43.81% (5.24 - 8.17 GHz) and 60.74% (3.75 - 7.00 GHz). The proposed circular-AGS antenna can achieve broader AR bandwidth and is thus ideal for broadband CP applications. The novelty of this research lies in the use of circular AGS to effectively enhance AR bandwidth, as opposed to rectangular AGS which is conventionally used in CP polarizers.
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A rectangular patch rectifying antenna array for wireless power transmission applications
(2017-12-19)
Wounchoum, Phairote
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Janpangngern, Pisit
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Pookkapund, Khanet
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Phongcharoenpanich, Chuwong
In this paper, a suspended-rectangular patch rectifying antenna (rectenna) array for 2.45 GHz wireless power transmission is presented. The proposed rectenna, which consists of an antenna array and a rectifying circuit, is designed to convert the RF signal into DC power. The antenna structure is designed by using a rectangular patch which radiates unidirectional pattern. The air substrate of the antenna is used to achieve high gain. The rectifying circuit is designed based on voltage diode with stub matching circuit. The dimension of the proposed antenna is square of 190 mm. The measured gain of this antenna is 14 dBi. At the distance of 1 m, the proposed rectifying circuit achieves the output voltage of 1.5 V and output current of 0.15 mA with a 1 MΩ resistor load and a transmitter power of 34.6 dBm EIRP.
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Design of planar dipole array antenna above square reflector for energy harvesting at 2.4 GHz band
(2016-01-01)
Pookkapund, Khanet
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Phongcharoenpanich, Chuwong
This paper presents a rectifying antenna (rectenna) which can harvest the RF wireless power at 2.45 GHz band. The proposed rectenna is designed to convert the wireless RF signal into DC power. The antenna structure consists of four printed dipoles located perpendicularly to one another to combine the pattern and increase the gain. The compact antenna radiates unidirectional pattern with the high gain. The rectifying circuit can convert the efficiency of 40% (200 mV) with resistor of 1 MΩ when the input power is 2 mW. The rectifying circuit part is designed based on the voltage diode with stub matching circuit.
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Planar array antenna for WPT system at 2.4 GHz
(2015-01-28)
Pookkapund, Khanet
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Boonying, Komkris
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Dentri, Sitthichai
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Phongcharoenpanich, Chuwong
This paper presents a rectifying antenna (rectenna) which can harvest the wireless power at 2.45 GHz band. The proposed antenna is designed to convert the wireless RF signal into DC power. The antenna structure consists of four printed dipoles located perpendicularly to one another to combine the pattern and increase the gain. The compact antenna radiates unidirectional pattern with the high gain. The rectifying circuit part is designed based on voltage diode with stub matching circuit.

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