| 1. |
- Alibakhshikenari, Mohammad, et al.
(author)
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A Comprehensive Survey on Antennas On-Chip Based on Metamaterial, Metasurface, and Substrate Integrated Waveguide Principles for Millimeter-Waves and Terahertz Integrated Circuits and Systems
- 2022
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In: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 10, s. 3668-3692
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Journal article (peer-reviewed)abstract
- Antennas on-chip are a particular type of radiating elements valued for their small footprint. They are most commonly integrated in circuit boards to electromagnetically interface free space, which is necessary for wireless communications. Antennas on-chip radiate and receive electromagnetic (EM) energy as any conventional antennas, but what distinguishes them is their miniaturized size. This means they can be integrated inside electronic devices. Although on-chip antennas have a limited range, they are suitable for cell phones, tablet computers, headsets, global positioning system (GPS) devices, and WiFi and WLAN routers. Typically, on-chip antennas are handicapped by narrow bandwidth (less than 10%) and low radiation efficiency. This survey provides an overview of recent techniques and technologies investigated in the literature, to implement high performance on-chip antennas for millimeter-waves (mmWave) and terahertz (THz) integrated-circuit (IC) applications. The technologies discussed here include metamaterial (MTM), metasurface (MTS), and substrate integrated waveguides (SIW). The antenna designs described here are implemented on various substrate layers such as Silicon, Graphene, Polyimide, and GaAs to facilitate integration on ICs. Some of the antennas described here employ innovative excitation mechanisms, for example comprising open-circuited microstrip-line that is electromagnetically coupled to radiating elements through narrow dielectric slots. This excitation mechanism is shown to suppress surface wave propagation and reduce substrate loss. Other techniques described like SIW are shown to significantly attenuate surface waves and minimise loss. Radiation elements based on the MTM and MTS inspired technologies are shown to extend the effective aperture of the antenna without compromising the antenna's form factor. Moreover, the on-chip antennas designed using the above technologies exhibit significantly improved impedance match, bandwidth, gain and radiation efficiency compared to previously used technologies. These features make such antennas a prime candidate for mmWave and THz on-chip integration. This review provides a thorough reference source for specialist antenna designers.
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| 2. |
- Alibakhshikenari, Mohammad, et al.
(author)
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An innovative antenna array with high inter element isolation for sub-6 GHz 5G MIMO communication systems
- 2022
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In: Scientific Reports. - : NATURE PORTFOLIO. - 2045-2322. ; 12:1
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Journal article (peer-reviewed)abstract
- A novel technique is shown to improve the isolation between radiators in antenna arrays. The proposed technique suppresses the surface-wave propagation and reduces substrate loss thereby enhancing the overall performance of the array. This is achieved without affecting the antenna's footprint. The proposed approach is demonstrated on a four-element array for 5G MIMO applications. Each radiating element in the array is constituted from a 3 x 3 matrix of interconnected resonant elements. The technique involves (1) incorporating matching stubs within the resonant elements, (2) framing each of the four-radiating elements inside a dot-wall, and (3) defecting the ground plane with dielectric slots that are aligned under the dot-walls. Results show that with the proposed approach the impedance bandwidth of the array is increased by 58.82% and the improvement in the average isolation between antennas #1&2, #1&3, #1&4 are 8 dB, 14 dB, 16 dB, and 13 dB, respectively. Moreover, improvement in the antenna gain is 4.2% and the total radiation efficiency is 23.53%. These results confirm the efficacy of the technique. The agreement between the simulated and measured results is excellent. Furthermore, the manufacture of the antenna array using the proposed approach is relatively straightforward and cost effective.
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| 3. |
- Ahmad, Sarosh, et al.
(author)
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A Compact CPW-Fed Ultra-Wideband Multi-Input-Multi-Output (MIMO) Antenna for Wireless Communication Networks
- 2022
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In: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 10, s. 25278-25289
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Journal article (peer-reviewed)abstract
- In this article, a compact coplanar waveguide (CPW) technique based ultra-wideband multiple-input-multiple-output (MIMO) antenna is proposed. The design is characterized by a broad impedance bandwidth starting from 3 GHz to 11 GHz. The overall size of the MIMO design is 60 x 60 mm(2) (1.24 x 1.24 lambda(2)(g) @ 3 GHz) with a thickness of 1.6 mm. To make the design ultra-wideband, the proposed MIMO antenna design has four jug-shaped radiating elements. The design is printed on a FR-4 substrate (relative permittivity of epsilon(r) = 4.4 and loss tangent of tan delta = 0.025). The polarization diversity phenomenon is realized by placing four antenna elements orthogonally. This arrangement increases the isolation among the MIMO antenna elements. The simulated results of the ultra-wideband MIMO antenna are verified by measured results. The proposed MIMO antenna has a measured diversity gain greater than 9.98, envelope correlation coefficient (ECC) less than 0.02, and good MIMO performance where the isolation is more than -20dB between the elements. The group delay, channel capacity loss (CCL), and the total active reflection coefficient (TARC) multiplexing efficiency and mean effective gain results are also analyzed. The group delay is found to be less than 1.2ns, CCL values calculated to be less than 0.4 bits/sec/Hz, while the TARC is below -10dB for the whole operating spectrum. The proposed design is a perfect candidate for ultra-wideband wireless communication systems and portable devices.
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| 4. |
- Elkorany, Ahmed Saad, et al.
(author)
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Implementation of a Miniaturized Planar Tri-Band Microstrip Patch Antenna for Wireless Sensors in Mobile Applications
- 2022
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In: Sensors. - : MDPI AG. - 1424-8220. ; 22:2
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Journal article (peer-reviewed)abstract
- Antennas in wireless sensor networks (WSNs) are characterized by the enhanced capacity of the network, longer range of transmission, better spatial reuse, and lower interference. In this paper, we propose a planar patch antenna for mobile communication applications operating at 1.8, 3.5, and 5.4 GHz. A planar microstrip patch antenna (MPA) consists of two F-shaped resonators that enable operations at 1.8 and 3.5 GHz while operation at 5.4 GHz is achieved when the patch is truncated from the middle. The proposed planar patch is printed on a low-cost FR-4 substrate that is 1.6 mm in thickness. The equivalent circuit model is also designed to validate the reflection coefficient of the proposed antenna with the S-11 obtained from the circuit model. It contains three RLC (resistor-inductor-capacitor) circuits for generating three frequency bands for the proposed antenna. Thereby, we obtained a good agreement between simulation and measurement results. The proposed antenna has an elliptically shaped radiation pattern at 1.8 and 3.5 GHz, while the broadside directional pattern is obtained at the 5.4 GHz frequency band. At 1.8, 3.5, and 5.4 GHz, the simulated peak realized gains of 2.34, 5.2, and 1.42 dB are obtained and compared to the experimental peak realized gains of 2.22, 5.18, and 1.38 dB at same frequencies. The results indicate that the proposed planar patch antenna can be utilized for mobile applications such as digital communication systems (DCS), worldwide interoperability for microwave access (WiMAX), and wireless local area networks (WLAN).
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| 5. |
- Fakharian, Mohammad M., et al.
(author)
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A Tunable Linear to Right-Handed Circularly Polarized THz Antenna Based on Graphene Switch
- 2022
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In: 32nd International Symposium of Space Terahertz Technology, ISSTT 2022. - : International Symposium on Space Terahertz Technology.
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Conference paper (peer-reviewed)abstract
- We propose a linear to right-handed circularly polarized tunable terahertz antenna. Polarization-switchable graphene is used to enable tunable polarization conversion and circular polarization. Polyimide is used as a substrate material for designing THz components due to its low absorption. By adjusting the graphene chemical potential to be between 0 eV to 0.8 eV, the polarization state in the 0.55 THz band can be obtained without changing the physical geometry. The proposed antenna has a significant potential for use in tunable terahertz devices and related applications.
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| 6. |
- Ahmad, Ikhlas, et al.
(author)
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Highly Compact GCPW-Fed Multi-Branch Structure Multi-Band Antenna for Wireless Applications
- 2022
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In: International Journal of Antennas and Propagation. - : Hindawi Limited. - 1687-5869 .- 1687-5877. ; 2022, s. 1-9
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Journal article (peer-reviewed)abstract
- In this work, we present a highly compact multi-branch structure multi-band antenna with a grounded coplanar waveguide (GCPW)-fed structure printed on 26 x 13 x 1.6 mm(3) sized FR-4 substrate having dielectric constant epsilon r of 4.3 and loss tangent delta of 0.02. In the proposed antenna, five branches are extended from the main radiator to provide multi-band behavior. Two branches are introduced at the upper end of the main radiator, effectively covering the lower bands, while the other three branches are introduced near the center of the main radiator to extend operation to higher bands. The designed antenna covers five different bands: 2.4 GHz, 4.5 GHz, 5.5 GHz, 6.5 GHz, and 7.8 GHz, with respective gain values of 1.34, 1.60, 1.83, 1.80, and 3.50 dBi and respective radiation efficiency values of 90, 88, 84, 75, and 89%. The antenna shows a good impedance bandwidth, ranging from 170 MHz to 3070 MHz. The proposed antenna is simulated in CST Microwave Studio, while its performance is experimentally validated by the fabrication and testing process. The antenna has potential applications for IoT, sub-6 GHz 5G and WLAN (both enablers for IoT), C-band, and X-band services.
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| 7. |
- Ahmad, Sarosh, et al.
(author)
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A Wideband Bear-Shaped Compact Size Implantable Antenna for In-Body Communications
- 2022
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In: Applied Sciences. - : MDPI AG. - 2076-3417. ; 12:6, s. 2859-
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Journal article (peer-reviewed)abstract
- Biomedical implantable antennas play a vital role in medical telemetry applications. These types of biomedical implantable devices are very helpful in improving and monitoring patients' living situations on a daily basis. In the present paper, a miniaturized footprint, thin-profile bear-shaped in-body antenna operational at 915 MHz in the industrial, scientific, and medical (ISM) band is proposed. The design is a straightforward bear-shaped truncated patch excited by a 50-Omega coaxial probe. The radiator is made up of two circular slots and one rectangular slot at the feet of the patch, and the ground plane is sotted to achieve a broadsided directional radiation pattern, imprinted on a Duroid RT5880 roger substrate with a typical 0.254-mm thickness (epsilon(r) = 2.2, tan delta = 0.0009). The stated antenna has a complete size of 7 mm x 7 mm x 0.254 mm and, in terms of guided wavelength, of 0.027 lambda(g) x 0.027 lambda(g) x 0.0011 lambda(g). When operating inside skin tissues, the antenna covers a measured bandwidth from 0.86 GHz to 1.08 GHz (220 MHz). The simulations and experimental outcomes of the stated design are in proper contract. The obtained results show that the calculated specific absorption rate (SAR) values inside skin of over 1 g of mass tissue is 8.22 W/kg. The stated SAR values are lower than the limitations of the federal communications commission (FCC). Thus, the proposed miniaturized antenna is an ultimate applicant for in-body communications.
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| 8. |
- Alharbi, Abdullah G., et al.
(author)
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Novel MIMO Antenna System for Ultra Wideband Applications
- 2022
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In: Applied Sciences. - : MDPI AG. - 2076-3417. ; 12:7
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Journal article (peer-reviewed)abstract
- The design of a 4 x 4 MIMO antenna for UWB communication systems is presented in this study. The single antenna element is comprised of a fractal circular ring structure backed by a modified partial ground plane having dimensions of 30 x 30 mm(2). The single antenna element has a wide impedance bandwidth of 9.33 GHz and operates from 2.67 GHz to 12 GHz. Furthermore, the gain of a single antenna element increases as the frequency increases, with a peak realized gain and antenna efficiency of 5 dBi and >75%, respectively. For MIMO applications, a 4 x 4 array is designed and analyzed. The antenna elements are positioned in a plus-shaped configuration to provide pattern as well as polarization diversity. It is worth mentioning that good isolation characteristics are achieved without the utilization of any isolation enhancement network. The proposed MIMO antenna was fabricated and tested, and the results show that it provides UWB response from 2.77 GHz to over 12 GHz. The isolation between the antenna elements is more than 15 dB. Based on performance attributes, it can be said that the proposed design is suitable for UWB MIMO applications.
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| 9. |
- Alibakhshikenari, Mohammad, et al.
(author)
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Broadband 3-D shared aperture high isolation nine-element antenna array for on-demand millimeter-wave 5G applications
- 2022
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In: Optik (Stuttgart). - : Elsevier BV. - 0030-4026 .- 1618-1336. ; 267
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Journal article (peer-reviewed)abstract
- The paper presents the results of a novel 3-D shared aperture 3 x 3 matrix antenna-array for 26 GHz band 5 G wireless networks. Radiation elements constituting the array are hexagonal-shaped patches that are elevated above the common dielectric substrate by 3.35 mm and excited through a metallic rod of 0.4 mm diameter. The rod protrudes through the substrate of 0.8 mm thickness. It is shown that by isolating each radiating element in the array with a wall suppresses unwanted electromagnetic (EM) wave interactions, resulting in improvement in the antenna's impedance matching and radiation characteristics. Moreover, the results show that by embedding hexagonalshaped slots in the patches improve the antenna's gain and radiation efficiency performance. The subwavelength length slots in the patches essentially transform the radiating elements to exhibit metasurface characteristics when the array is illuminated by EM-waves. The proposed array structure has an average gain and radiation efficiency of 20 dBi and 93%, respectively, across 24.0-28.4 GHz. The isolation between its radiation elements is greater than 22 dB. Compared to the unslotted array the improvement in isolation between radiating elements is greater than 11 dB, and the gain and efficiency are better than 10.5 dBi, and 25%, respectively. The compact array has a fractional bandwidth of 16% and a form factor of 20 x 20 x 3.35 mm(3).
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| 10. |
- Alibakhshikenari, Mohammad, et al.
(author)
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Dual-Polarized Highly Folded Bowtie Antenna with Slotted Self-Grounded Structure for Sub-6 GHz 5G Applications
- 2022
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In: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 70:4, s. 3028-3033
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Journal article (peer-reviewed)abstract
- In this paper, a novel dual-polarized highly-folded self-grounded Bowtie antenna that is excited through I-shaped slots is proposed for applications in sub-6GHz 5G multiple-input-multiple-output (MIMO) antenna systems. The antenna consists of two pairs of folded radiation petals whose base is embedded in a double layer of FR-4 substrate with a common ground-plane which is sandwiched between the two substrate layers. The ground-plane is defected with two I-shaped slots located under the radiation elements. Each pair of radiation elements are excited through a microstrip line on the top layer with RF signal that is 180° out of phase with respect to each other. The RF signal is coupled to the pair of feedlines on the top layer through the I-shaped slots from the two microstrip feedlines on the underside of the second substrate. The proposed feed mechanism gets rid of the otherwise bulky balun. The Bowtie antenna is a compact solution with dimensions of 32 32 33.8 mm3. Measured results have verified that the antenna operates over a frequency range of 3.1–5 GHz and exhibits an average gain and antenna efficiency in the vertical and horizontal polarizations of 7.5 dBi and 82.6%, respectively.
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