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    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.
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    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.
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    Coupling Minimization of Dual-Port Meta-Surface MIMO Antenna With Pin Vias for IoT Technology
    (2025-01-01)
    Supreeyatitikul, Nathapat
    ;
    Boonpoonga, Akkarat
    ;
    Phongcharoenpanich, Chuwong
    ;
    Lerttheerachanchai, Wirote
    ;
    Konpang, Jessada
    This study proposed a single-layer, compact, dual-port meta-surface multiple-input multiple-output (MIMO) antenna for Internet of Things (IoT) applications. Coupling between ports is effectively minimized using pin vias, which connects the meta-surface to the ground plane and functions as an LC resonator circuit to suppress useless frequencies. Here, L and C represent inductance and capacitance, respectively. Additionally, pin vias reduces mutual coupling by mitigating concentrated current distributions on the meta-surface components, achieving high isolation. The simulated results reveal a return loss bandwidth (RLBW) spanning 3.76-7.4 GHz (70% at a center frequency of 5.2 GHz) with isolation (S<inf>12</inf>) exceeding 19 dB. Furthermore, the envelope correlation coefficient is below 0.035, and the diversity gain reaches 9.82 dB. The antenna achieves a maximum gain of 5.54 dBi at 4.3 GHz. This demonstrates that the pin vias decoupling technique is highly effective for coupling reduction in meta-surface MIMO antennas.
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    Broadband Two-Array Metasurface-Gridded MIMO Antenna with Dual-CP Bi-Directional Capabilities
    (2025-01-01)
    Supreeyatitikul, Nathapat
    ;
    Kakhong, Khwanlada
    ;
    Prasong, Pusit
    ;
    Phongcharoenpanich, Chuwong
    ;
    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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    Two-Port Circularly Polarized Slot-Coupled Antenna Using Novel AMC Structure
    (2025-01-01)
    Supreeyatitikul, Nathapat
    ;
    Kakhong, Khwanlada
    ;
    Phongcharoenpanich, Chuwong
    ;
    Konpang, Jessada
    This research introduces a two-port circularly polarized (CP) slot-coupled MIMO antenna with an novel artificial magnetic conductor (AMC) reflector for Vehicle-to-Everything (V2X) technology. The proposed antenna comprises two layers separated by an air gap: the upper layer includes the dual-element slot-integrated MIMO antenna with microstrip-line feeds and defected ground structures (I-shaped slots) for coupling reduction, while the lower layer integrates an 8 × 8 array of AMC units. The AMC enhances gain and improves radiation properties through its reflective behavior. Measured results confirm the antenna's suitability for V2X applications, achieving a wide return loss bandwidth (RLBW) of 32% (4.72 - 6.61 GHz), axial ratio bandwidth (ARBW) of 21.18% (5.2 - 6.45 GHz), and isolation greater than 19 dB. The antenna attains a peak gain of 8.6 dBic at 5.9 GHz, with an envelope correlation coefficient below 0.003 and diversity gain exceeding 9.98 dB. The key innovation of this work lies in the combination of CP slot-integrated MIMO design with a novel AMC structure to enhance gain and isolation, making it highly effective for V2X wireless networks in modern vehicular communication networks.
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    Non Voltage Feedback Bluetooth Power Supply
    (2024-01-01)
    Kongjareansuk, Sayree
    ;
    Konpang, Jessada
    ;
    Purahong, Boonchana
    This paper introduces a voltage regulator circuit for various Bluetooth devices, designed to operate without voltage feedback. The circuit achieves a 5.1% error margin at a 5V(DC) output voltage and employs a minimal number of components, rendering it a practical solution. The results demonstrate a reduction in harmonic noise in the output voltage during operation. Measurement outcomes, featuring a comparison of harmonic signals, are presented using a digital storage oscilloscope (100MHz 2GSa/s).
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    Design and Experimentation of CP Sequential-Rotated Patch Antenna for Nanosatellite Technology
    (2024-01-01)
    Supreeyatitikul, Nathapat
    ;
    Phaebua, Kittisak
    ;
    Phongcharoenpanich, Chuwong
    ;
    Konpang, Jessada
    This paper proposes a circularly polarized (CP) sequential-rotated patch antenna for nanosatellite communication systems. The proposed CP sequential-rotated patch antenna comprised of 2 × 2 corner-truncated rectangular patch with a slot, and sequentially rotated feeding (SRF). The SRF was used to improve impedance matching and CP bandwidth. These patches and SRF were fabricated on Rogers 5880 substrate. Moreover, this antenna was integrated with radome and enclosures for space environment hazards. The measured results at 2.1 GHz (center frequency) achieved RLBW of 73.33% (1.46 - 3 GHz) and ARBW of 23.33% (1.87 - 2.36 GHz). The optimal gain (RHCP) was 5 dBic at 2.25 GHz with bi-directional radiation, rendering the proposed antenna suitable for S-band nanosatellite technology.
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    Enhancing Bandwidth of Circularly Polarized DRA Using Embedded Slot-Coupled Patch
    (2024-01-01)
    Supreeyatitikul, Nathapat
    ;
    Phongcharoenpanich, Chuwong
    ;
    Konpang, Jessada
    This paper proposes a bandwidth enhancement technique for circularly polarized (CP) dielectric resonator antenna (DRA) using the embedded slot-coupled patch. The proposed CP DRA for mid-band 5G applications consisted of an aperture-coupled feed, a dice-shaped dielectric resonator (DR), and an embedded slot-coupled patch. A slot-coupled feed included cross-aperture ground plane (upper substrate) and microstrip-line feed (lower substrate). The dice-shaped DR sits at the center of the cross-aperture ground plane. The slot-coupled patch was embedded into DR for bandwidth enhancement. The DR usually functioned as a resonance cavity, producing TEll1 mode. The embedded slot-coupled patch can generate the resonance frequency mode (TM01 and TMl0) at a higher frequency, resulting in a wide reflection coefficient bandwidth and ARBW. The results of simulation reflection coefficient bandwidth and ARBW at center frequency (3.5 GHz) achieved 44% (3.12 - 4.66 GHz) and 36.57% (3.23 - 4.51 GHz). The peak RHCP gain was 8.7 dBic at 4.5 GHz with right-hand circular polarization, rendering the proposed CP DRA with embedded slot-coupled patch suitable for mid-band 5G wireless networks.