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Coupling Minimization of Dual-Port Meta-Surface MIMO Antenna With Pin Vias for IoT Technology
(2025-01-01)
Supreeyatitikul, Nathapat
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Boonpoonga, Akkarat
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Phongcharoenpanich, Chuwong
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Lerttheerachanchai, Wirote
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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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Clutter Effect on a Combination of Microwave Imaging and Target Identification Using Ground-Penetrating Radar
(2024-01-01)
Yochanang, Kiattisak
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Bannawat, Lakkhana
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Boonpoonga, Akkarat
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Phongcharoenpanich, Chuwong
This paper presents an experimental investigation of the effect of clutter on the performance of microwave imaging and target identification using ground-penetrating radar (GPR) for buried objects. Signals collected by the GPR were formed to be B-scan and 3D images to carry out the microwave imaging of buried objects. Poles extracted using the short-time matrix pencil method from a late-time response of the received signal collected at a specific position were exploited to identify buried objects. The experiment was set up by constructing a large box filled with sand where an L-shaped metallic sheet was buried. The GPR was installed along with a 2-dimensional scanner above the box to image and identify the buried metallic sheet. In order to investigate the effect of the clutter on the performance of the GPR-based microwave imaging and target identification, small rocks were arranged on the sand surface, and their density was then varied. The experimental results have shown that clutter density significantly affects the sharpness of the B-scan and 3D images. The rocks result in an additional surface layer in the images. Moreover, the results have also shown that the clutter does not affect the performance of the identification of the buried object. From the results, the poles obtained from the GPR scanning inside and outside the buried object region differed. This confirms that the poles of the buried object should be different from those without the object. The poles of the buried object remain constant, although rocks on the sand surface exist since the clutter affects only the early-time response (not the late-time response). With varying clutter densities, the underlying poles were significantly changed, but this does not affect the identification of the buried object.
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Artificial Magnetic Conductor as Planar Antenna for 5G Evolution
(2023-01-01)
Kanjanasit, Komsan
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Osklang, Pracha
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Jariyanorawiss, Terapass
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Boonpoonga, Akkarat
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Phongcharoenpanich, Chuwong
A 5G wireless system requests a high-performance compact antenna device. This research work aims to report the characterization and verification of the artificial magnetic conductor (AMC) metamaterial for a high-gain planar antenna. The configuration is formed by a double-side structure on an intrinsic dielectric slab. The 2-D periodic pattern as an impedance surface is mounted on the top surface, whereas at the bottom surface the ground plane with an inductive narrow aperture source is embedded. The characteristic of the resonant transmission is illustrated based on the electromagnetic virtual object of the AMC resonant structure to reveal the unique property of a magnetic material response. The characteristics of the AMC metamaterial and the planar antenna synthesis are investigated and verified by experiment using a low-cost FR4 dielectric material. The directional antenna gain is obviously enhanced by guiding a primary field radiation. The loss effect in a dielectric slab is essentially studied having an influence on antenna radiation. The verification shows a peak of the antenna gain around 9.7 dB at broadside which is improved by 6.2 dB in comparison with the primary aperture antenna without the AMC structure. The thin antenna profile of λ/37.5 is achieved at 10 GHz for 5G evolution. The emission property in an AMC structure herein contributes to the development of a low-profile and high-gain planar antenna for a compact wireless component.
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Gain Enhancement of Circularly Polarized Aperture-Coupled Microstrip Patch Antenna Using Partially Reflective Surface
(2022-01-01)
Supreeyatitikul, Nathapat
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Boonpoonga, Akkarat
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Phongcharoenpanich, Chuwong
This paper proposes a compact and high-gain circularly polarized H-shaped aperture-coupled cornertruncated square microstrip patch antenna with partially reflective surface for C-band applications. The H-shaped aperture-coupled corner-truncated square patch antenna performed a right-handed circularly polarized radiation. The PRS was utilized to enhance bandwidth and gain, which placed above (air gap) the CP H-shaped aperture-coupled microstrip patch antenna. The PRS contained 8×8 arranged-periodically rhombus-shaped unit cells on the FR-4 single-substrate. Simulations of the proposed CP antenna with PRS at 4.5 GHz (center frequency) achieved impedance bandwidth, axial ratio bandwidth, and maximum gain of 37.7% (4-5.7 GHz), 13.3% (4.3-4.9 GHz), and 12 dBi at 4.7 GHz. The overall dimension antenna was 100 mm x 100 mm x 43.2 mm. Essentially, a high gain of the proposed antenna is suitable for C-band frequency.
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High-Gain Wideband CP S-shaped Slot Antenna with Metasurface Reflector for UHF-RFID Readers
(2022-01-01)
Supreeyatitikul, Nathapat
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Boonpoonga, Akkarat
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Phongcharoenpanich, Chuwong
This research proposes a high-gain wideband circularly polarized (CP) S-shaped slot antenna with metasurface (MTS) reflector for UHF-RFID handheld readers. The proposed antenna consisted of the S-shaped slot antenna with coplanar waveguide feed on the upper substrate and 4 × 4 periodically-arranged plus-sign-shaped slot MTS unit cells on the lower substrate functioning as a reflector. The MTS reflector was utilized to realize the high-gain of the CP S-shaped slot antenna. To achieve wide impedance bandwidth (IBW) and axial ratio bandwidth (ARBW), the evolution of the antenna was developed in four stages. The simulated IBW and ARBW of the Antenna IV (proposed antenna) at 0.9 GHz (center frequency) were 37.7% (0.66-1 GHz) and 27.7% (0.72-0.97 GHz), respectively. In addition, the maximum gain was 7.56 dBic at 0.78 GHz with left-hand circular polarization (LHCP) radiation characteristics. The dimension of the proposed antenna was 0.35?0 × 0.35?0 × 0.195?0.
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Z-Shaped Metasurface-Based Wideband Circularly Polarized Fabry-Pérot Antenna for C-Band Satellite Technology
(2022-01-01)
Supreeyatitikul, Nathapat
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Boonpoonga, Akkarat
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Phongcharoenpanich, Chuwong
This research proposes a low-profile Z-shaped metasurface (MTS)-based wideband circularly polarized (CP) Fabry-Pérot antenna for C-band satellite communication. The proposed low-cost and low-complexity CP Fabry-Pérot antenna is realized by using three substrate layers: upper, middle, and lower. The substrates are of FR-4 type with a dielectric constant of 4.3 and loss tangent of 0.025. The upper substrate contains 9× 9 periodically-arranged Z-shaped MTS unit cells functioning as the partially reflecting surface and circular polarization conversion, and at the center of the middle substrate sits a corners-truncated square patch. The lower substrate consists of a copper plate with an H-shaped slot at the center of the ground plane and a microstrip feed line. The lower and middle substrates function as the source antenna. The periodic Z-shaped MTS unit cells are utilized to enhance the impedance bandwidth (IBW) and gain of the source antenna and also to convert linearly polarized into CP wave. The antenna dimension is 1.5λ 0 × 1.5λ 0 × 0.51λ 0. Simulations are performed and experiments carried out. The measured IBW and axial ratio bandwidth are 64% (4.4- 7.6 GHz) and 18% (4.4- 5.3 GHz) at the center frequency of 5 GHz. In addition, the proposed antenna scheme achieves a measured 3-dB boresight gain bandwidth of 30% (4.3- 5.8 GHz) with the maximum gain of 12.88 dBic at 4.7 GHz, rendering the proposed Z-shaped MTS-based CP Fabry-Pérot antenna operationally suitable for satellite communication. In essence, the novelty of this research lies in the use of the low-cost and low-complexity Z-shaped MTS unit cell to effectively enhance the antenna gain and convert LP into CP wave.
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Metasurface-based Circularly Polarized Dual-Port MIMO Antenna for C-band Uplink Applications
(2022-01-01)
Supreeyatitikul, Nathapat
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Boonpoonga, Akkarat
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Phongcharoenpanich, Chuwong
The rectangular-shaped metasurface (MTS)- based circularly polarized (CP) dual-port MIMO antenna was proposed. The proposed rectangular-shaped MTS-based CP dual-port MIMO antenna included two substrate layers (upper and lower). The periodic 4×4 rectangular-shaped MTS elements on the upper layer functioned as CP polarizers. Also, the lower substrate layer comprised the microstrip probe feed and ground plane which generated a linearly polarized (LP) wave. The proposed rectangular-shaped MTS-based CP dual-port MIMO antenna at 5.3 GHz achieved impedance bandwidth (IBW) of 30.9% (4.86 - 6.5 GHz) and axial ratio (ARBW) of 14% (5.16 - 5.9 GHz). The maximum gain was 7.3 dBi at 5.1 GHz. The ECC was lower than 0.002, and DG was greater than 9.98 dB between entire frequency ranges. The direction of the radiation was right-hand circular polarization (RHCP). The dimension of proposed rectangular-shaped MTS-based CP dual-port MIMO antenna was 1.342λ0 × 0.652λ0 × 0.0372λ0.
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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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Mics/ism meander-line microstrip antenna encapsulated in oblong-shaped pod for gastrointestinal tract diagnosis
(2021-06-01)
Kawdungta, Supakit
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Boonpoonga, Akkarat
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Phongcharoenpanich, Chuwong
In light of the growth in demand for multiband antennas for medical applications, this research proposes a MICS/ISM meander-line microstrip antenna encapsulated in an oblong-shaped pod for use in diagnoses of the gastrointestinal tract. The proposed antenna is operable in the Medical Implant Communication System (MICS) and the Industrial, Scientific and Medical (ISM) bands. The antenna structure consists of a meander-line radiating patch, a flipped-L defected ground plane, and a loading resistor for antenna miniaturization. The MICS/ISM microstrip antenna encapsulated in an oblong-shaped pod was simulated in various lossy-material environments. In addition, the specific absorption rate (SAR) was calculated and compared against the IEEE C95.1 standard. For verification, an antenna prototype was fabricated and experiments carried out in equivalent liquid mixtures, the dielectric constants of which resembled human tissue. The measured impedance bandwidths (|S11| ≤ −10 dB) for the MICS and ISM bands were 398–407 MHz and 2.41– 2.48 GHz. The measured antenna gains were −38 dBi and −13 dBi, with a quasi-omnidirectional radiation pattern. The measured SAR was substantially below the maximum safety limits. As a result, the described MICS/ISM microstrip antenna encapsulated in an oblong-shaped pod can be used for real-time gastrointestinal tract diagnosis. The novelty of this work lies in the use of a meander-line microstrip, flipped-L defected ground plane, and loading resistor to miniaturize the antenna and realize the MICS and ISM bands.
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Effect of antenna frequency bands on the resolution of GPR images
(2017-12-19)
Yochanang, Kiattisak
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Boonpoonga, Akkarat
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Akkaraekthalin, Prayoot
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Bannawat, Lakkhana
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Phongcharoenpanich, Chuwong
This paper presents an investigation of the effect of the antenna frequency band on the ground penetrating radar (GPR) image resolution. The investigation is achieved through simulations. In the simulations, two Scutcheon antennas are modeled as the receiving and transmitting antennas. A cross-shaped object is buried under the ground constructed with the dielectric material. The Gaussian pulses with different frequency bands is transmitted and propagated to the buried object. The EM wave scattered from the object is collected to form the GPR image. The simulation results obtained from different frequency band show that the resolution of the GPR image obtained from the wider frequency band is better than that of the GPR image obtained from narrower one.

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