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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
;
Pookkapund, Khanet
;
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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Corner-truncated patch antenna with parasitic elements and circular feed slot for S-band CubeSat applications
(2025-12-01)
Hemachai, Thanaphon
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Dentri, Sitthichai
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Janpangngern, Pisit
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Phakphisut, Watid
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Torrungrueng, Danai
This study presents a corner-truncated patch antenna with symmetrically loaded parasitic elements and a circular feed slot designed for CubeSat S-band communication applications. The antenna design evolves through successive stages, integrating corner truncations, a slit-ring structure, and segment-circular parasitic patches to enhance impedance matching and polarization performance. In its final configuration, a dual-stacked arrangement with inter-substrate spacing and a vertical capacitive feed further improves current distribution symmetry and broadens the operational bandwidth. Parametric analysis validates the effectiveness of each antenna design refinement, demonstrating improvements in impedance bandwidth, axial ratio bandwidth, and gain performance. The fabricated prototype achieves a wide impedance bandwidth from 1.65 GHz to 2.70 GHz, fully encompassing the CubeSat uplink (2.025–2.110 GHz) and downlink (2.200–2.290 GHz) frequency ranges. It maintains an axial ratio below 3 dB across 1.97 GHz to 2.32 GHz, ensuring efficient circular polarization. Additionally, a stable gain of approximately 7.50 dBic at 2.025 GHz supports reliable communication with ground stations. The combination of compact structure, low profile, and wideband circular polarization makes the proposed antenna a promising candidate for CubeSat communication systems. The novelty of this research lies in the integration of a corner-truncated patch, symmetrically loaded segment-circular parasitic elements, and a circular slit-ring capacitive feed within a dual-stacked substrate configuration to achieve wideband circular polarization and stable unidirectional radiation.
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Investigations of a Circularly Polarized Slotted Corner-Truncated Microstrip Patch Antenna with Split-Ring AMC Reflector
(2025-01-01)
Ainthachot, Chalanthon
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Janpangngern, Pisit
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Dentri, Sitthichai
;
Phongcharoenpanich, Chuwong
This paper presents the design and development of a circularly polarized slotted corner-truncated microstrip patch antenna integrated with a split-ring artificial magnetic conductor (AMC) metasurface for WLAN applications at 2.45 GHz. The antenna design incorporates structural adaptations, such as slotted apertures and corner truncations, to enhance impedance matching and achieve circular polarization. To further improve performance, a split-ring AMC metasurface was employed, resulting in enhanced polarization purity and bandwidth. The proposed design achieves an impedance bandwidth (|S<inf>11</inf>| below -10 dB) from 2.33 GHz to 2.75 GHz and an axial ratio (AR) below 3 dB over the frequency range of 2.40 GHz to 2.55 GHz, and a peak gain of approximately 4.40 dBic at 2.45 GHz. Simulated results are validated by measured results of the fabricated prototype, demonstrating close agreement and confirming the robustness of the design methodology. This work highlights an innovative approach to compact and high-performance antenna design, ensuring its suitability for modern WLAN communication systems.
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Conceivable Design of a Wideband Unidirectional Antenna using Truncated Microstrip Patches for S-Band Applications
(2025-01-01)
Hemachai, Thanaphon
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Janpangngern, Pisit
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Dentri, Sitthichai
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Phongcharoenpanich, Chuwong
This paper presents the conceivable design of a wideband unidirectional antenna suitable for CubeSat applications operating in the S-band frequency ranges of 2.025-2.110 GHz (uplink band) and 2.200-2.290 GHz (downlink band). The antenna employs a truncated microstrip patch design combined with additional parasitic patches to achieve circular polarization. It is printed on an RT/duroid<sup>®</sup> 5880 substrate with a thickness of 0.6 mm and a relative permittivity of 2.2. The design consists of a central truncated radiating patch and four segment-circular parasitic patches, positioned near the edges of the substrate to enhance bandwidth and axial ratio performance, which is crucial for achieving circular polarization. The antenna is excited using a coaxial probe feed to ensure efficient energy transfer and proper impedance matching. Simulation results demonstrate that the antenna achieves a wide impedance bandwidth covering 1.80 GHz to 2.40 GHz with a reflection coefficient (|S11|) below -10 dB. The axial ratio remains below 3 dB across the frequency range of 2.025 GHz to 2.290 GHz, confirming circular polarization, with a minimum axial ratio of 1.34 dB at 2.25 GHz. Additionally, the antenna exhibits a stable gain of approximately 7.28 dBic at 2.15 GHz, making it suitable for CubeSat communication systems requiring reliable and efficient signal transmission. To further strengthen the contribution of this research, a performance comparison with existing CubeSat antennas is provided, along with a discussion of potential environmental impacts in space, such as temperature variations and radiation effects. Future work will focus on prototyping, experimental validation, and optimizing the antenna design for different mission scenarios, including scaling for other frequency bands and multi-antenna configurations.
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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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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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Broadband CP corner-truncated microstrip antenna with irregularly hexagonal AMC for 2.45 GHz applications
(2024-06-01)
Wichaidit, Purichaya
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Dentri, Sitthichai
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Janpangngern, Pisit
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Lertwiriyaprapa, Titipong
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Krairiksh, Monai
This research proposes a compact broadband circularly polarized (CP) corner-truncated microstrip antenna with irregularly hexagonal artificial magnetic conductor (AMC) for 2.45 GHz WLAN applications. The corners of the radiating patch are diagonally truncated to realize circular polarization and improve axial ratio. A 5[Formula presented]5 irregularly hexagonal AMC array is employed to enhance the axial ratio bandwidth (ARBW) and antenna gain. In addition, a tri-section meandering feedline is used to realize impedance matching and improve the impedance bandwidth (IBW). The AMC array is used to manipulate electromagnetic waves by suppressing surface currents and back lobe, resulting in reduced back radiation and enhanced front-to-back ratio. The simulated IBW and ARBW are 50.9% (1.86 – 3.13 GHz) and 19.3% (2.24 – 2.72 GHz) respectively, with a maximum gain of 8.9 dBic at 2.45 GHz. The measured IBW and ARBW are 42.42% (1.95 – 3.0 GHz) and 29.4% (2.03 – 2.73 GHz), with a maximum gain of 8.6 dBic. The simulated half power beamwidth (HPBW) of the proposed antenna scheme in the xz plane at 2.24 GHz, 2.45 GHz, and 2.72 GHz are 67°, 62°, and 51°, respectively. The corresponding HPBW in the yz plane are 60°, 55°, and 62°. The simulated AR beamwidth in the xz plane at 2.24 GHz, 2.45 GHz, and 2.72 GHz are 177°, 164°, and 88°, respectively. The corresponding AR beamwidth in the yz plane are 148°, 106°, and 124°. The simulated cross polarized (XP) levels at 2.45 GHz are below -19.35 dB for both planes. The measured HPBW in the xz plane at 2.24 GHz, 2.45 GHz, and 2.72 GHz are 69°, 64°, and 50°, respectively. The corresponding HPBW in the yz plane are 65°, 54°, and 37°. The measured AR beamwidth in the xz plane at 2.24 GHz, 2.45 GHz, and 2.72 GHz are 161°, 200°, and 104°, respectively. The corresponding AR beamwidth in the yz plane are 162°, 85°, and 90°. The measured XP levels at 2.45 GHz are below -15.62 dB for both planes. The radiation pattern is unidirectional. Essentially, the proposed broadband CP antenna scheme is suitable for the WLAN frequency band and other 2.45 GHz wireless communication technologies. The novelty of this research lies in the use of the tri-section meandering feedline and the irregularly hexagonal AMC array to enhance IBW and ARBW.
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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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Wideband Bidirectional Circularly Polarized S-Slot Antenna with Dielectric Superstrate
(2024-01-01)
Luadang, Bancha
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Janpangngern, Pisit
;
Phongcharoenpanich, Chuwong
This paper presents the design of a circularly polarized (CP) wideband S-slot antenna with a bidirectional radiation pattern, using a dielectric superstrate (DS) to increase the gain. The antenna achieves an enhance axial ratio (AR) bandwidth and reduced back lobe of radiation pattern. The S-slot antenna is positioned midway between a rectangular dielectric superstrate and an S-slot radiating element, which has a dielectric constant of εr = 4.3. The DS acts as a lens, refracting the electric field to combine the antenna beam and increase the antenna gain. For performance evaluation, the S-slot radiating element without the DS was compared to the proposed antenna. The antenna size is optimized for a center frequency of 5.5 GHz. The square DS contributes significantly to the bandwidth ratio, achieving an axial ratio AR ≤ 3 dB across the design frequency range (|S11| ≤ -10 dB) of 4.0-6.25 GHz. This antenna design is suitable for wireless communications and 5G sub-6 GHz applications, such as in long bridge/tunnel areas, coal mines communications, radio frequency identification (RFID) systems, and various wireless communication systems.
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CMA-Based Quadruple-Cluster Leaf-Shaped Metasurface-Based Wideband Circularly-Polarized Stacked-Patch Antenna Array for Sub-6 GHz 5G Applications
(2023-01-01)
Supreeyatitikul, Nathapat
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Janpangngern, Pisit
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Lertwiriyaprapa, Titipong
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Krairiksh, Monai
;
Phongcharoenpanich, Chuwong
This research proposes a quadruple-cluster leaf-shaped metasurface (MTS)-based circularly-polarized (CP) stacked-patch antenna array with hybrid coupler feed network for sub-6 GHz 5G applications. In the study, the leaf-shaped MTS-based CP stacked-patch antenna is characterized by characteristic mode analysis (CMA). In the antenna design, one cluster of the quadruple-cluster leaf-shaped MTS-based antenna array consists of 4×4 leaf-shaped MTS elements; and the hybrid coupler feed network is used to enhance impedance bandwidth (IBW), axial ratio bandwidth (ARBW), and antenna gain. Simulations are carried out and an antenna prototype is fabricated and experiments undertaken. The measured IBW, ARBW, and maximum gain at the center frequency (4 GHz) are 62.5% (3.4- 5.9 GHz), 21% (3.8- 4.54 GHz), and 9.04 dBic at 3.9 GHz. The novelty of this research lies in the use of: (i) the CMA concept to design and develop the leaf-shaped wideband MTS-based stacked-patch antenna with CP radiation pattern; and (ii) a low-complexity hybrid coupler feed network to enhance the IBW, ARBW and gain.

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