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A Flexible and Compact UWB MIMO Antenna with Dual-Band-Notched Double U-Shaped Slot on Mylar® Polyester Film
(2025-09-01)
Chutchavong, Vanvisa
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Chanwattanapong, Wanchalerm
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Wongsin, Norakamon
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Rakluea, Paitoon
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Tangjitjetsada, Maleeya
Ultra-wideband (UWB) technology is a crucial facilitator for high-data-rate wireless communication due to its extensive frequency spectrum and low power consumption. Simultaneously, multiple-input multiple-output (MIMO) systems have garnered considerable attention owing to their capability to enhance channel capacity and link dependability. This article discusses the development of small, high-performance MIMO UWB antennas with mutual suppression capabilities to fully use the benefits of both technologies. Additionally, the suggested antenna features a straightforward design and dual-band-notched characteristics. The antenna structure includes two radiating elements measuring 85 × 45 mm2. These elements use a rectangular patch provided by a coplanar waveguide (CPW). Double U-shaped slots are incorporated into the rectangular patch to introduce dual-band-notched properties, which help mitigate interference from WiMAX and WLAN communication systems. The antenna is fabricated on a Mylar® polyester film substrate of 0.3 mm in thickness, with a dielectric constant of 3.2. According to the measurement results, the suggested antenna functions efficiently across the frequency spectrum of 2.29 to 20 GHz, with excellent impedance matching throughout the bandwidth. Furthermore, it provides dual-band-notched coverage at 3.08–3.8 GHz for WiMAX and 4.98–5.89 GHz for WLAN. The antenna exhibits impressive performance, including favorable radiation attributes, consistent gain, and little mutual coupling (less than −20 dB). Additionally, the envelope correlation coefficient (ECC) is extremely low (ECC < 0.01) across the working bandwidth, which indicates excellent UWB MIMO performance. This paper offers an appropriate design methodology for future flexible and compact UWB MIMO systems that can serve as interference-resilient antennas for next-generation wireless applications.
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Deployable Wideband Circularly Polarized S-Band Antenna Array for CubeSat Applications
(2024-01-01)
Supreeyatitikul, Nathapat
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Akkaraekthalin, Prayoot
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Kawdungta, Supakit
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Phongcharoenpanich, Chuwong
A broadband circularly polarized (CP) S-band antenna array for CubeSat technology was proposed. The proposed CP antenna array comprised of 2 × 2 rectangular-shaped ring patches and sequentially rotated feeding structure. Besides, the sequentially rotated feeding structure is utilized to match impedance. This antenna is made of single-layered Roger RT5880 substrate. The simulation results at 2 GHz achieved IBW of 81% (1.3 - 2.92 GHz) and ARBW of 25% (1.85 - 2.35 GHz). The optimal RHCP gain is 4.69 dBic at 2.25 GHz. The half-power beamwidth at 2 GHz is 71.51°. The radiation patterns are RHCP characteristic. The proposed CP S-band antenna array with sequentially rotated feeding structure is deployed with the CubeSat platform, resulting in the proposed CP antenna array befitting CubeSat technology.
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Wideband dielectric properties of silicon and glass substrates for terahertz integrated circuits and microsystems
(2021-05-01)
Chudpooti, Nonchanutt
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Duangrit, Nattapong
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Burnett, Andrew D.
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Freeman, Joshua R.
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Gill, Thomas B.
This paper presents a comprehensive study of the optical and electrical dielectric material properties of six commonly-used silicon and glass substrates at terahertz (THz) frequencies, including refractive index, absorption coefficient, dielectric constant and loss factor. The material characterization techniques used in this paper feature THz time-domain transmission and reflection spectroscopy with the measurement frequencies from 0.5 THz up to a maximum of 6.5 THz. Of the six selected dielectric and semiconductor substrates, two are silicon wafers with resistivities ranging from 0.001 to 0.02 Ω-cm. From the measurement results, loss tangents of the selected silicon wafers range from 0.680 to 5.455 and the dielectric constants are from 1.079 to 17.735. The four other wafers are all glass-based substrates: D263 glass, Borofloat 33 glass, fused silica and Sapphire. From the measurements, it is found that the THz dielectric properties vary considerably between the substrate samples e.g. dielectric constants range from 1.925 to 3.207 while loss tangents are from 0.042 × 10-3 to 0.127. Most of the selected silicon and glass-based substrates are quite useful for many THz applications, e.g., THz integrated circuits (THz ICs), THz microsystem technologies (THz MSTs) and THz system-on-a-chip (THz SoC) and system-on-substrate (SiP).
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Single-Layer Wideband CP CPW-Fed Antenna based on Staircase-Shape Metasurface
(2021-01-01)
Supreeyatitikul, Nathapat
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Akkaraekthalin, Prayoot
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Phongcharoenpanich, Chuwong
This research proposed a single-layer wideband circularly polarized (CP) coplanar waveguide (CPW)-fed antenna based on staircase-shaped metasurface (MTS) for C-band applications. The proposed CPW-fed antenna was a single-layer, which consisted of 4 × 4 periodic staircase-shaped MTS on the upper layer, a CPW feed, and a rectangular slot ground plane on the lower layer. A linearly polarized (LP) wave was generated by a CPW with a slot ground plane and converted to a circularly polarized wave by staircase-shaped MTS elements. The dimensions of the proposed antenna were 0.54 × 0.54 × 0.04 at the lowest operating frequency. The simulated results of impedance bandwidth (IBW) and axial ratio (ARBW) at the center frequency of 5.2 GHz were 67.3% (4.1 - 7.6 GHz) and 15.9% (4.8 - 5.7 GHz), respectively. The maximum gain was 5.6 dBi at 5.3 GHz. The radiation patterns of the proposed CPW-fed antenna based on staircase-shaped MTS were right-hand circular polarization (RHCP) characteristic radiation at the operating frequency.
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Single-fed broadband CP bidirectional antenna with double-layer diagonally aligned plates for universal UHF-RFID applications
(2020-01-01)
Dentri, Sitthichai
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Pookkapund, Khanet
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Luadang, Bancha
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Akkaraekthalin, Prayoot
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Phongcharoenpanich, Chuwong
This research proposes a single-fed broadband circularly polarized (CP) bidirectional antenna operable in 840-960 MHz frequency band for readers of universal UHF-RFID applications. The proposed antenna is comprised of upper-layer conductor, lower-layer conductor, and wall patches. The upper-layer conductor consists of two diagonally aligned rectangular copper plates with a feeding gap at the center, and the lower-layer conductor is of two diagonally adjoined rectangular plates. The upper- and lower-layer conductors are adjoined with the wall patches. The diagonal alignment technique of the upper- and lower-layer plates was used to realize circular polarization and improve 3-dB axial ratio (AR) bandwidth. The double layers were deployed to improve impedance bandwidth (|S11| < -10 dB) and achieve bidirectional radiation pattern. The simulated impedance bandwidth and 3-dB AR bandwidth were 772.19-1014.6 MHz (27.13%) and 675-1000 MHz (38.80%), and the corresponding measured results were 759-1011 MHz (28.47%) and 648-1110 MHz (52.55%). The simulated LHCP/RHCP half-power beamwidth (HPBW), 3-dB AR beamwidth, and gain were 56° - 90°/54° - 92°, 60° - 104°, and 4.94 - 5.89 dBic, while the corresponding measured results were 52° - 98°/62° - 97°, 96° - 126°, and 4.28 - 5.72 dBic. As a result, the single-fed broadband CP bidirectional antenna is applicable to universal UHF-RFID readers. Besides, the novelty of this research lies in the use of diagonal alignment of conducting plates to achieve circular polarization and wider AR bandwidth.
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Curved meander line resonators for chipless RFID sensors
(2019-09-01)
Suwalak, Rattapong
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Phongcharoenpanich, Chuwong
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Akkaraekthalin, Prayoot
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Torrungrueng, Danai
This paper presents a chipless RFID sensor based on the curved meander line resonator. The sensor is designed and printed on Fr4-substrate with thickness of 0.8 mm. The resonator on the RFID sensor acts as a data bit for identification, where we use only one bit in this paper for illustration. Transmitting and receiving antennas on the RFID sensor are properly designed to sense the dielectric property of the material under test. From the results, it can operate from 1.8-2.5 GHz. The gain is 2.14 dBi at the resonant frequency of 2.28 GHz. Therefore, it can be candidate as a RFID sensor with a nondestructive testing technique.
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A triple-band high-gain planar dipole with double interdigital structure for indoor LTE and WLAN base stations
(2019-02-01)
Archevapanich, Tuanjai
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Chomtong, Pongsathorn
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Chutchavong, Vanvisa
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Akkaraekthalin, Prayoot
This paper presents a triple-band antenna using interdigital technique based on dipole structure at a frequency of 1.8 GHz. Using this technique, harmonic frequency bands can be generated as desired, resulting in the resonance frequencies of the second and third harmonics at 2.4 and 5.2 GHz, respectively. The proposed antenna consists of two square brass plates with an overall size of 63 × 64 mm2. The antenna bandwidths are found to be 410 MHz (1.59–2.00 GHz), 70 MHz (2.40–2.47 GHz), and 790 MHz (4.99–5.78 GHz), and the gains obtained are 9.63, 8.95, and 8.97 dB, respectively. The radiation patterns are directional at all frequency bands. Therefore, the proposed antenna can be appropriately used for indoor long-term evolution (LTE) and wireless local area network (WLAN) base stations. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
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Triband compact printed antenna for 2.4/3.5/5 GHz WLAN/WiMAX applications
(2019-01-01)
Osklang, Pracha
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Phongcharoenpanich, Chuwong
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Akkaraekthalin, Prayoot
This research presents a triband compact printed antenna for WLAN and WiMAX applications. The antenna structure consists of a folded open stub, long and short L-shaped strips, and asymmetric trapezoid ground plane. Besides, it is of simple structure and operable in 2.4 GHz and 5 GHz (5.2/5.8 GHz) WLAN and 3.5/5.5 GHz WiMAX bands. The folded open stub and long and short L-shaped strips realize impedance matching at 2.4, 3.5, 5.2, and 5.8 GHz, and the asymmetric trapezoid ground plane fine-tunes impedance matching at 5.2, 5.5, and 5.8 GHz. In addition, the equivalent circuit model consolidated into lumped elements is also presented to explain its impedance matching characteristics. In this study, simulations were carried out, and a prototype antenna was fabricated and experimented. The simulation and experimental results are in good agreement. Specifically, the simulated and experimental radiation patterns are omnidirectional at 2.4, 3.5, and 5.2 GHz and near-omnidirectional at 5.5 and 5.8 GHz. Furthermore, the simulated and measured antenna gains are 1.269-3.074 dBi and 1.10-2.80 dBi, respectively. Essentially, the triband compact printed antenna covers 2.4 GHz and 5 GHz (5.2/5.8 GHz) WLAN and 3.5/5.5 GHz WiMAX frequency bands and thereby is a good candidate for WLAN/WiMAX applications.
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Circularly Polarized Omnidirectional Antenna with Dipole Core and Diagonally Adjoined Parasitic Braces for ISM Band Applications
(2019-01-01)
Dangkham, Piyapong
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Dentri, Sitthichai
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Phongcharoenpanich, Chuwong
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Akkaraekthalin, Prayoot
This research proposes a circularly polarized (CP) single-fed omnidirectional dipole antenna operable in 2.45 GHz frequency for the industrial, scientific, and medical (ISM) radio band applications. The proposed antenna consisted of bisectional dipole core, a pair of quarter-wave baluns, and four diagonally adjoined parasitic braces. The bisectional dipole core was utilized to improve the antenna gain and realize omnidirectional radiation pattern, and the quarter-wave baluns were to symmetrize the current on the bisectional core. The four parasitic braces collectively generated circular polarization. In the study, simulations were conducted using CST Microwave Studio and a prototype antenna fabricated. To validate, experiments were carried out, and simulation and experimental results compared. The finding revealed good agreement between the simulation and experimental results. Essentially, in addition to achieving an antenna gain of 2.07 dBic, the proposed CP single-fed omnidirectional antenna is suited to ISM frequency band applications.
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Recent Advances in RFID Sensors for Construction Material Monitoring Applications (Invited Paper)
(2018-07-02)
Suwalak, Rattapong
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Lertsakwimarn, Kittima
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Phongcharoenpanich, Chuwong
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Akkaraekthalin, Prayoot
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Torrungrueng, Danai
This paper presents recent advances in radiofrequency identification (RFID) sensors for monitoring applications of construction material products (CMPs) (e.g., light weight concrete (LWC) and concrete). These RFID sensors can offer both identification and sensing capabilities simultaneously without any additional sensors. The research and development of both chipped and chipless RFID sensors will be discussed during presentation, including their interesting applications.

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