KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 80

Some of the metrics are blocked by your
consent settings
Machine Learning-Optimized Dual-Band LoRa Elliptical Patch Antenna in LoRa Communication System for Waterborne Microplastic Detection
(2026-02-01)
Romputtal, Adisak
;
Phongcharoenpanich, Chuwong
This research proposes a dual-band LoRa elliptical patch antenna for the LoRa communication system to detect waterborne microplastics. The proposed LoRa communication system comprises a LoRa sensor node board and an IoT-LoRa gateway board. The LoRa sensor node board is used to capture microplastic images using a digital camera and collect analog signal data from an 8 × 8 photodiode array which detects the reflected light from microplastic fragments. The data are transmitted using a LoRa elliptical patch antenna in the sensor node board, operating at 0.915 GHz for long-range data transfer. The IoT-LoRa gateway board is used to forward data received from the LoRa sensor node board to a cloud server via the internet, and the stored data are accessible and viewable via a smartphone. In this research, the antenna design is optimized by using machine learning (ML) algorithms, unlike conventional antenna design methods which rely on the manual and iterative process. The ML-optimized dual-band LoRa elliptical patch antenna covers the LoRa, UHF RFID, and ZigBee frequency bands, with an omnidirectional radiation pattern. The measured impedance bandwidths (IBWs) are 8.93% (0.868–0.949 GHz) and 12.69% (2.36–2.68 GHz) for the lower and upper frequency bands, respectively, with the corresponding impedance matching (|S<inf>11</inf>|) of –23.02 dB at 0.907 GHz and −27.27 dB at 2.52 GHz. Two ML-optimized LoRa elliptical patch antennas are subsequently integrated into the LoRa communication system, that is, one on the LoRa sensor node board and other on the IoT-LoRa gateway board. Furthermore, prior to indoor and outdoor experiments, the ML-driven waterborne microplastic detection scheme with the LoRa communication system is trained and tested using camera-captured images and analog signal-converted images from the photodiode array. The ML-driven microplastic detection scheme can classify different types of microplastics in water, achieving an accuracy of 100% for all types of microplastics. The detection scheme is also capable of identifying the presence of microplastics in water, achieving an overall accuracy of 98.5%. The originality of this work lies in the use of ML algorithm to optimize the antenna design and to streamline identification and detection of microplastics in water.
Some of the metrics are blocked by your
consent settings
Dual-Band CP Metasurface-Array Antenna with Sequential-Phase Feed Network for C-Band Operation
(2026-01-01)
Kakhong, Khwanlada
;
Phaebua, Kittisak
;
Phongcharoenpanich, Chuwong
;
Supreeyatitikul, Nathapat
This paper presents a four-cluster dual-band circularly polarized (CP) metasurface (MTS)-array antenna integrated with a sequential-phase feed (SPF) network for C-band applications. The antenna is implemented on dual-layer FR-4 substrates, incorporating both big- and small-sized MTS-array elements per cluster, with a tilted square-slot ground plane and microstrip-line feed. The SPF network excites each cluster with equal amplitude and 90<sup>°</sup> phase shifts, significantly enhancing return loss bandwidth (RLBW), axial ratio bandwidth, and realized gain. The simulated results demonstrate RLBW of 3.08 - 4.51 GHz and 4.94 - 8 GHz, and ARBWs of 3.08 - 4.66 GHz and 5.27 - 6.42 GHz for the lower and higher operating bands, respectively. The corresponding highest RHCP gains are 6.15 dBic at 3.8 GHz and 4 dBic at 6 GHz. The proposed antenna design achieves bi-directional radiation patterns and shows substantial performance improvements over conventional dual-band CP MTS-array antennas.
Some of the metrics are blocked by your
consent settings
EBG-backed ultrawideband circularly polarized Archimedean spiral antenna scheme for IoT applications
(2025-12-01)
Luadang, Bancha
;
Ainthachot, Chalanthon
;
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.
Some of the metrics are blocked by your
consent settings
Corner-truncated patch antenna with parasitic elements and circular feed slot for S-band CubeSat applications
(2025-12-01)
Hemachai, Thanaphon
;
Dentri, Sitthichai
;
Janpangngern, Pisit
;
Phakphisut, Watid
;
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.
Some of the metrics are blocked by your
consent settings
A circularly polarized tunable frequency circular patch antenna for S-band space base application
(2025-05-01)
Waranon, Likhit
;
Dentri, Sitthichai
;
Phakphisut, Watid
;
Krairiksh, Monai
;
Phongcharoenpanich, Chuwong
This research proposes a unidirectional circularly polarized tunable frequency circular patch antenna scheme for S-band uplink satellite communications. In the antenna scheme, the circular radiating patch is enclosed by 4×8 rectangular-shaped auxiliary elements along the +x, −x, +y, and −y−axes. To shift the resonant frequency of the antenna to lower frequencies, the auxiliary elements on the four axes are uniformly shorted. There are nine shorting configurations (configurations A – I) corresponding to the S-band uplink chain (2.025 GHz to 2.110 GHz). Besides, the circular polarization is switchable between right- (RHCP) and left-hand circular polarization (LHCP) by relocating the feed point from the +y axis for RHCP to +x axis for LHCP. Switching mechanisms dynamically reconfigure the antenna by modifying its electrical length to support multiple frequency bands, all of which maintain circular polarization. Since the proposed antenna scheme is intended for the S-band uplink frequency of 2.06 GHz, measurements are carried out with configuration F of the antenna scheme. The measured impedance bandwidth (|S<inf>11</inf>|≤-10 dB) and axial ratio bandwidth (AR<3 dB) are 6.2% and 4.49%, with the maximum gain of 6.54 dBic for RHCP and LHCP. The radiation pattern is of unidirectionality. Furthermore, the proposed antenna scheme meets the qualification sine vibration and random vibration test requirements. The proposed antenna scheme is thus suitable for S-band uplink satellite communications. The novelty of this research lies in the use of the auxiliary elements of various shorting configurations to achieve frequency tunability; and the alteration of the feed point location to switch between RHCP and LHCP.
Some of the metrics are blocked by your
consent settings
Gain Enhancement of a Dual-Band S-Patch Antenna Array for 5G Application
(2025-04-01)
Udomratanasiri, Dhanapon
;
Kawdungta, Supakit
;
Pansomboon, Rassamitut
;
Lang, Alongkorn
;
Phongcharoenpanich, Chuwong
This paper proposes the dual-band S-patch antenna with gain enhancement by using the planar array configuration and dielectric superstrate. The design of the proposed antenna is focused on the base station antenna in the 5G frequency bands n41 (2.6 GHz) and n78 (3.5 GHz). The dual-band S-patch antenna is arranged in the 2 × 6 elements planar array antenna and the FR4 dielectric superstrate is on the top of the array. The simulated results indicated that the operating frequency of 2.55–2.65 GHz and 3.46–3.61 GHz with uni-directional radiation pattern. The antenna gain can be improved with 18.70 dBi at 2.6 GHz and 19.30 dBi at 3.5 GHz. The prototype antenna is fabricated and the measured results are in good agreement. With the simple design of the proposed antenna, it would be useful for the installation of the base station antenna.
Some of the metrics are blocked by your
consent settings
A dual-band rectangular shape incorporated into circular patch antenna for 2.4/5 GHz wireless local area network applications
(2025-02-01)
Lamultree, Suthasinee
;
Somsanook, Nattakarn
;
Narkkoht, Wararak
;
Phongcharoenpanich, Chuwong
This research exhibits a design of a dual-band patch antenna (DBPA) implemented by a rectangular shape incorporated into a circular patch together with a pair of half-wavelength inverted U-slots (HWIUSs) with the single feed for 2.4/5 GHz wireless local area network (WLAN) applications. For this work, the HWIUSs are key in designing a dual-band antenna. The DBPA is fed by a 50-Ohm microstrip line, printed on a copper layer overlaid on an FR4 substrate with a relative permittivity of 4.3 and height of 1.6 mm, while the bottom layer is backed by a partial ground plane. An antenna prototype with a dimension of 0.384λL×0.304λL×0.013λL was contrived and admeasured to verify the simulation. The measurement provides a nearly omnidirectional pattern with a 2.55 and 3.3 dBi peak gain covering a dual-band 10 dB return loss bandwidth of 15% (2.4–2.8 GHz) and 20% (4.96–5.86 GHz), respectively. Noticeably, simulated |S11| and radiation patterns are reasonable following experimental results showing its potential in 2.4/5 GHz WLAN services.
Some of the metrics are blocked by your
consent settings
Analysis of Wireless Power Transfer between Near-Field Antennas Using the Bi-Characteristic-Impedance Transmission Line (BCITL) Model
(2025-01-01)
Phaebua, Kittisak
;
Phongcharoenpanich, Chuwong
;
Lertwiriyaprapa, Titipong
;
Torrungrueng, Danai
;
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).
Some of the metrics are blocked by your
consent settings
Prism-Shaped Dielectric Resonator Circularly Polarized Antenna with Loop-Shaped Metasurface-Enhanced Reflector
(2025-01-01)
Supreeyatitikul, Nathapat
;
Lertwiriyaprapa, Titipong
;
Phongcharoenpanich, Chuwong
;
Konpang, Jessada
This paper proposes a prism-shaped dielectric resonator (DR) -based antenna with circularly polarized (CP) characteristics for C-band wireless systems. This antenna comprised a prism-shaped DR and single-layer substrate. The prism-shaped DR is on the upper-side substrate. Besides, a rod-shaped probe was plugged into a DR and connected by an SMA connector on the lower-side substrate. A loop-shaped metasurface-enhanced reflector is employed to improve bandwidth (i.e., RLBW and ARBW) and antenna gain. A regularly spaced array of 7 × 7 loop-shaped metasurface unit structures is positioned on the upper substrate side. The simulation RLBW and ARBW results at 5.8 GHz (center frequency) are 34% (5.22 - 7.2 GHz) and 16% (5.27 - 6.2 GHz). This antenna radiates left-hand circular polarization with an optimal maximum gain at 5.5 GHz of 6.7 dBic, making it suitable for C-band wireless networks.
Some of the metrics are blocked by your
consent settings
Wideband Circularly Polarized Sequentially-Rotated Cubic-Shaped Dielectric Resonator Array Antenna
(2025-01-01)
Supreeyatitikul, Nathapat
;
Lertwiriyaprapa, Titipong
;
Phongcharoenpanich, Chuwong
;
Konpang, Jessada
This study proposes a cubic-shaped dielectric resonator (DR) broadband circularly polarized (CP) array antenna for S-band networks. The design includes 2 × 2 cubic-shaped DR units and a substrate. The upper and lower substrates feature a split-annular aperture ground plane and a sequential-phase feed. Employing the sequential-phase feed, the proposed array antenna aims to enhance performance metrics, including RLBW, ARBW, and antenna gain. Simulation results indicate a RLBW of 56.25% (2.25 - 3.6 GHz) and an ARBW of 43.33% (2.38 - 3.42 GHz). The optimal gain achieved is 9.14 dBic at 3.3 GHz. Furthermore, the array antenna demonstrates right-hand circular polarization (RHCP) characteristics, rendering it suitable for S-band technology.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results