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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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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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Analysis of Wireless Power Transfer between Near-Field Antennas Using the Bi-Characteristic-Impedance Transmission Line (BCITL) Model
(2025-01-01)
Phaebua, Kittisak
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Phongcharoenpanich, Chuwong
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Lertwiriyaprapa, Titipong
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Torrungrueng, Danai
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Chou, Hsi Tseng
Analysis of wireless power transfer (WPT) between near-field (NF) antennas is proposed by using a bi-characteristic- impedance transmission line (BCITL) model. In particular, misalignment between small NF transmitting (TX) and receiving (RX) antennas degrades the power transfer efficiency (PTE). The proposed novel optimization procedure, based on the BCITL model, effectively maximizes WPT area, which is strongly influenced by antenna characteristics, the RX antenna's position, and the load reflection coefficient (Γ<inf>L</inf>) at each misaligned position. In such misalignment, Γ<inf>L</inf> ≠ 0, which is a crucial parameter in impedance matching to broaden the WPT area. This letter investigates the Γ<inf>L</inf> impact on the PTE at misaligned positions based on BCITL parameters, providing a new optimization framework that adapts to varying degrees of misalignment. In simulation and measurement validation, it is demonstrated that this BCITL model may estimate an optimal Γ<inf>L</inf> (Γ<inf>L</inf> ≠ 0) to produce WPT areas much broader than those using the conventional matching condition (Γ<inf>L</inf> = 0).
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Compact High-Gain Dual-band Patch Antenna With Dielectric Superstrate for Wi-Fi 6 Applications
(2023-01-01)
Muangrung, Bhuwakorndit
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Lang, Alongkorn
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Torrungrueng, Danai
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Phongcharoenpanich, Chuwong
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Kawdungta, Supakit
The compact high-gain dual-band double circular patch antenna with dielectric superstrate is introduced for Wi-Fi 6 applications. The double circular patch antenna can be operated at two frequency bands of 2.41-2.54 GHz and 4.94-6.03 GHz. The dielectric superstrate and parasitic patches are employed in front of the antenna to enhance the antenna gain. From simulated results, the dielectric superstrate and parasitic patches can improve the antenna gain. The proposed antenna has |S11| less than-10 dB in both operating frequency bands, unidirectional radiation pattern, and gain of 4.8 dBi at 2.45 GHz and 4.57 dBi at 5.5 GHz.
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Dual-Band Band-Stop Filter using Multiple Hexagonal Microstrip Line for Chipless RFID Sensor
(2023-01-01)
Suwalak, Rattapong
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Lertsakwimarn, Kittima
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Lertwiriyaprapa, Titipong
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Phongcharoenpanich, Chuwong
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Torrungrueng, Danai
The dual-band band-stop filter using a hexagonal-shape microstrip line is presented in this paper. The chipless RFID with the band-stop filter used to determine the relative permittivity of material under test and identify characteristic based on the unique responded signal from the chipless RFID sensor. This paper proposed the multiple microstrip line structure with a quarter-wavelength transformer to generate an identification (ID) code, i.e., ID-01, ID-10, and ID-11 at the center frequency of 2.2 GHz and 2.7 GHz. From the results, the proposed chipless RFID sensor can be identified and determined the relative permittivity of the LWC.
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Flexible Chipless RFID Sensor for permittivity sensing of Cylindrical Impedance Surface
(2023-01-01)
Suwalak, Rattapong
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Phongcharoenpanich, Chuwong
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Torrungrueng, Danai
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Lertwiriyaprapa, Titipong
This paper presents the chipless RFID sensor characteristics when placed on the cylindrical impedance surface. The chipless RFID sensor is designed based on the multiple resonant printed on the flexible substrate of Polyimide (r = 3.5 and tan δ = 0.0027). The humidity of the material under test is identified using the chipless RFID sensor based on the multi-resonators. This chipless sensor can be generated 5 bits of identification (ID). Furthermore, the orientation effect of the plane wave is studied. The results shows that the flexible chipless RFID sensor can be identified the different dielectric constant that related with the water content in the material. Therefore, this sensor can be applied to recognize the humidity state of material under test.
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Dual-Band Circularly Polarized Omni-Directional Biconical Antenna With Double-Circular Parallelepiped Elements for WLAN Applications
(2022-01-01)
Janpangngern, Pisit
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Torrungrueng, Danai
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Krairiksh, Monai
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Phongcharoenpanich, Chuwong
This research proposes a novel dual-band (2.45/5.80 GHz) omnidirectional circularly polarized (CP) biconical antenna with double-circular parasitic parallelepiped elements for wireless local area network (WLAN) applications. The proposed dual-band CP antenna scheme consisted of a biconical radiating structure surrounded by inner- and outer-circular parallelepiped elements that convert linearly polarized electric fields into CP fields. Simulations were performed to optimize the antenna parameters, and an antenna prototype was fabricated and experiments were conducted. The measured impedance bandwidths (IBWs) were 44.4% (1.84 - 2.89 GHz) and 4.56% (5.73 - 5.99 GHz) for the lower- (2.4 GHz) and upper-frequency (5.80 GHz) bands, respectively. The corresponding 3-dB axial ratio bandwidths (ARBWs) were 11.22% (2.27 - 2.54 GHz) and 10.49% (5.6 - 6.2 GHz). The radiation patterns of the dual-band antenna scheme were omnidirectional left-hand circular polarization, with the measured antenna gains of 3.2 dBic and 8.5 dBic at 2.45 and 5.80 GHz, respectively. The simulated and measured results were reasonably agreeable. Despite the narrow IBW and ARBW for the upper-frequency band, the bandwidths adequately covered the target upper frequency band, rendering the proposed CP omnidirectional biconical antenna scheme operationally suitable for WLAN applications. Furthermore, the novelty of this research lies in the use of a biconical radiating structure augmented with double-circular parasitic parallelepiped elements to realize circular polarization for dual-band WLAN applications.
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Dual-Band Band-Stop Filter for Chipless RFID Sensor in a Dielectric Constant Determination
(2022-01-01)
Suwalak, Rattapong
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Phaebua, Kittisak
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Lertwiriyaprapa, Titipong
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Phongcharoenpanich, Chuwong
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Torrungrueng, Danai
This paper presents the dual-band band-stop filter to operate with the chipless RFID tag acts as the RFID sensor for a dielectric constant determination and the identification characteristic based on the signature responded signal from the chipless RFID sensor system. The proposed dual-band filter can generate the dual-stop band of the frequency of 2.2 GHz and 2.7 GHz. The 3-bits identification (ID) i.e., ID-01, ID-10, and ID-11 are obtained from the proposed filter. In addition, the chipless RFID sensor with band-stop filter technique can be determined the dielectric constant of RT/Duroid5880, Fr4 (Glass Epoxy), and low-Temperature cofired ceramic (LTCC).
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Study of the limitation of characteristic modes using the far-field based reconstruction technique for complex antenna structures
(2021-05-19)
Eardprab, Sanchai
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Phongcharoenpanich, Chuwong
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Torrungrueng, Danai
This paper presents the study of the characteristic mode simulation and the limitation of the far-field based reconstruction technique for complex antenna structures. The characteristic modes can also be reconstructed based on the radiated far fields obtained from simulations or measurements. Traditionally, the characteristic modes are usually calculated by using the method of moments (MoM) to determine the impedance matrix and associated eigenvalues and eigenvectors in order to calculate the current distribution on antenna structures and associated radiated far fields. In an inverse approach, the characteristic modes can also be reconstructed based on the radiated far fields obtained from simulations or measurements. The characteristic modes of a relevant simplified antenna structure and the related far fields are used to approximate characteristic modes of more complex antenna structures. It has been shown in the literature that characteristic modes can be reconstructed with good accuracy for simplified antenna structures with small perturbation. However, when the antenna structures are more complex or the structure perturbation is larger over the important part of antenna structures associated with dominant characteristic modes, the far field based reconstruction of these modes may not be sufficiently accurate due to significant mode perturbation. In this paper, the limitation of the far-field based reconstruction technique is investigated. The parametric studies of the structure perturbation are performed in terms of scaling and location on antenna structures to determine the limitation of the method. The proper perturbation remaining dominant modes are discussed as well.
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Chipless RFID sensing for dielectric property of light weight concrete
(2021-05-19)
Suwalak, Rattapong
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Phaebua, Kittisak
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Phongcharoenpanich, Chuwong
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Lertwiriyaprapa, Titipong
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Pathoumvanh, Somsanouk
This paper presents a passive chipless RFID tag (Electromagnetic sensor) based on the modified printed monopole antenna with a frequency filter technique. The proposed chipless RFID sensor is the wireless sensor technology with the nondestructive technique (NDT) testing. This proposed RFID tag is designed to obtain both determination and identification (ID) properties for a sensor application. To determine the dielectric constant of MUT under test, the circular monopole tag antenna is modified using adding the elliptical shape to achieve the wideband operating frequency. Moreover, this sensor is used the stripline frequency filter technique to obtain the 1-bit ID at the frequency of 2.77 GHz. The CST Microwave Studio simulator program uses to design and optimize the passive chipless RFID parameters. Simulated results show the proposed chipless RFID sensor can identify and determine the dielectric property of the LWC under test.

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