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Publication Metadata only A Compact Low SAR Value Circularly Polarized Wearable Antenna Design for 5G Applications(Institute of Electrical and Electronics Engineers Inc., 2022) Gokdemir, Melih; Saeidi, Tale; Karamzadeh, Saeid; Akleman, Funda; Gokdemir, Melih, Department of Electronics and Communication Engineering, İstanbul Teknik Üniversitesi, Istanbul, Turkey; Saeidi, Tale, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Akleman, Funda, Department of Electronics and Communication Engineering, İstanbul Teknik Üniversitesi, Istanbul, TurkeyIn this study, a wideband wearable antenna is proposed for 5G and IoT applications. The presented circularly polarized coplanar waveguide antenna has a compact size (16mm x 21.5mm). The other result of the novel design which makes this antenna one of the best choices for wearable applications is its low SAR values. These values are 0.0846 and 0.0497 W/kg for mass densities of 1g and 10g, respectively. © 2022 Elsevier B.V., All rights reserved.Publication Metadata only A Wearable Circularly Polarized Antenna for 5G Applications, 5G Uygulamalari için Giyilebilir Dairesel Polarizasyonlu Anten(Institute of Electrical and Electronics Engineers Inc., 2022) Ibrahim, Assim; Tetık, Evrim; Karamzadeh, Saeid; Ibrahim, Assim, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Tetık, Evrim, Department of Electrical and Electronic Engineering, İstanbul Arel Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey5G technology for health care is a considerable demand nowadays due to the revolution in IoT devices. A dual-band antenna on a Rogers RT/duroid 5880 substrate with a dielectric constant of 2.2 and thickness of 0.508 mm, is presented for 3.4 GHz and 5.85GHz frequency bands. The top layer of the proposed antenna consists of a square part that includes an inductive meander line. It is connected to an I-shape, which is merged with reversed L-shaped, the higher resonant frequency excited at 3.4 GHz. In the bottom layer, after the reflector is made, the inductive meander line is created and connected to a reversed U-shape. The proposed antenna of size 19 x 12 mm2 reveals to perform well for frequencies between 3.37 and 3.47 GHz. It has an axial ratio less than 3dBi and a peak gain of 1.7 dBi that increases after adding a multi-layer of a human hand up to 8 dBi. © 2022 Elsevier B.V., All rights reserved.Publication Metadata only Metamaterial-Based Circularly Polarized Wearable Antenna for ISM and 5G Communications(Institute of Electrical and Electronics Engineers Inc., 2022) Saeidi, Tale; Gokdemir, Melih; Karamzadeh, Saeid; Saeidi, Tale, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Gokdemir, Melih, Elctronics and Communication Engineering Department, İstanbul Teknik Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyA multiband, small, high gain, low specific absorption rate (SAR), and circularly polarized (CP) textile wearable antenna is designed on a layer of denim (ϵr = 1.3, h= 0.787 mm) substrate. The antenna is comprised of a rectangular patch that feeds through an inset transmission line and four tilted periodic slots to enhance the bandwidth (BW) and achieve circular polarization. A layer of fleece fabric (ϵr = 1.04, h= 3 mm) attached to a layer of full ShieldIt to create maximum directivity and minimize SAR value. Then, the antenna is loaded with six arrays of Split Ring Resonator (SRR) on the same antenna layer to enhance the BW that had been reduced after adding the second layer. The antenna works for both ISM and 5G communication systems as it operates at 2.35-2.45 GHz and 3.3-3.9 GHz, respectively. It has the maximum directive gain of 8.52 dBi, acceptable SAR values for both standards with total dimensions of 54 × 56 mm2. In addition, the antenna's CP is examined, showing AR values of < 3 dB at the working BW with a decent agreement between the simulation and measurement outcomes. © 2022 Elsevier B.V., All rights reserved.Publication Metadata only High gain couple feed multiband wearable antenna for 5G and sub-6 GHz communications(John Wiley and Sons Inc, 2022) Saeidi, Tale; Karamzadeh, Saeid; Saeidi, Tale, Department of Electrical and Electronic Engineering, İstinye Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyA multi-band, small, high gain, low specific absorption rate (SAR), and circularly polarized (CP) textile wearable antenna fed using aperture coupled technique is designed on two layers of denim ((Formula presented.), h = 0.787 mm as feeding layer) and felt ((Formula presented.), h = 1.5 mm as a resonating layer) textile substrates. The antenna is designed on two layers with two relative permittivities to enhance the BW and reduce the negative mutual coupling. Afterward, another layer of denim with the complete ground of ShieldIt conductor is added to decrease the SAR value along with the directive gain. The antenna works for Industrial, Scientific, and Medical (ISM), 5G, and sub-6 GHz communication systems as it operates at 2.45–2.55 GHz and 3.8 GHz (3.6–4.15 GHz), and 5.6 GHz (5.55–5.65 GHz), respectively. The proposed antenna has the maximum directive gain of 8.35 dBi, acceptable SAR values at a 10 mm distance from the human body for both standards. In addition, the antenna's CP is examined, showing AR values of <2.5 dB at the working BW. Finally, the proposed antenna is measured and compared with the simulation results. A good agreement exists between simulation and measurement results. © 2022 Elsevier B.V., All rights reserved.Publication Open Access A Miniaturized Full-Ground Dual-Band MIMO Spiral Button Wearable Antenna for 5G and Sub-6 GHz Communications(MDPI, 2023) Saeidi, Tale; Abdullah Al-Gburi, Ahmed Jamal; Karamzadeh, Saeid; Saeidi, Tale, Department of Electrical and Electronic Engineering, İstinye Üniversitesi, Istanbul, Turkey; Abdullah Al-Gburi, Ahmed Jamal, Center for Telecommunication Research and Innovation (CeTRI), Universiti Teknikal Malaysia Melaka, Malacca, Malaysia; Karamzadeh, Saeid, Intelligent Wireless System, Silicon Austria Labs GmbH, Graz, Austria, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyA detachable miniaturized three-element spirals radiator button antenna integrated with a compact leaky-wave wearable antenna forming a dual-band three-port antenna is proposed. The leaky-wave antenna is fabricated on a denim (εr = 1.6, tan δ = 0.006) textile substrate with dimensions of 0.37 λ0 × 0.25 λ0 × 0.01 λ0 mm3 and a detachable rigid button of 20 mm diameter (on a PTFE substrate εr = 2.01, tan δ = 0.001). It augments users’ comfort, making it one of the smallest to date in the literature. The designed antenna, with 3.25 to 3.65 GHz and 5.4 to 5.85 GHz operational bands, covers the wireless local area network (WLAN) frequency (5.1–5.5 GHz), the fifth-generation (5G) communication band. Low mutual coupling between the ports and the button antenna elements ensures high diversity performance. The performance of the specific absorption rate (SAR) and the envelope correlation coefficient (ECC) are also examined. The simulation and measurement findings agree well. Low SAR, <−0.05 of LCC, more than 9.5 dBi diversity gain, dual polarization, and strong isolation between every two ports all point to the proposed antenna being an ideal option for use as a MIMO antenna for communications. © 2023 Elsevier B.V., All rights reserved.Publication Metadata only A Miniaturized Multi-Frequency Wide-Band Leaky Wave Button Antenna for ISM/5G Communications and WBAN Applications(John Wiley and Sons Inc, 2023) Saeidi, Tale; Karamzadeh, Saeid; Saeidi, Tale, Department of Electrical and Electronic Engineering, İstinye Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Intelligent Wireless System, Silicon Austria Labs GmbH, Graz, Austria, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyA low-profile multi-frequency leaky wave button antenna for body-centric communications is presented. A leaky wave antenna loaded with U-slots (a combination of U-slots and slits) and tapered slot structures to improve the radiation efficiency, broadside radiation pattern, and widen the steering range is designed. Furthermore, it comprises a whole ground to meet the Specific Absorption Rate standard requirements based on the known standards. The antenna's performances are examined for on and off-body conditions. For demonstration, a prototype is implemented, and the measurement is performed on the chest. The antenna operates at multi bands of 1.7–3.3 GHz (Industrial, Scientific, and Medical and 5G communication) and 4.15–10 GHz (sub-6 GHz and X-band communications). The peak gains of 6.9 and 8.2 dBi were obtained for on and off- body conditions, respectively. Furthermore, the antenna offers maximum radiation efficiencies of 89.3% and 99.3% for on-body and free-space conditions. The specific absorption rate (SAR) values obtained for body-centric communications meet the regulation requirements (e.g., on body tissue at 3.2 GHz, it is 0.78 (1 g) and 0.44 (10 g) W/kg). With an overall miniaturized size, the proposed button antenna could be integrated with clothes. In addition, a multi-wide bandwidth, circularly polarized radiation, a small size, high efficiency and gain, and low SAR values prove that the proposed antenna can be a potential candidate for wireless body area network and simultaneous wireless information and power transfer applications. © 2023 Elsevier B.V., All rights reserved.Publication Metadata only Evaluating Substrate Influence on Rectangular and Circular Microstrip Patch Antennas for 5G(Institute of Electrical and Electronics Engineers Inc., 2024) Göksel, Fatih; Karamzadeh, Saeid; Kolosovs, D.; Göksel, Fatih, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Intelligent Wireless System, Silicon Austria Labs GmbH, Graz, Austria, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyMicrostrip Patch Antennas (MSPAs) are favored for their low production cost, compact size, lightweight nature, and adaptability to planar and non-planar surfaces. They are particularly suitable for wideband and multi-frequency operations, making them ideal for sub-6 GHz applications in 5G devices. This study aims to design and compare rectangular and circular MSPAs using six different substrates: FR4 Glass Epoxy (dielectric constant 4.3), ROGERS DT5880 (2.2), ROGERS 4003C (3.3), Teflon (2.1), Arlon AD300A (3), and Alumina (9.9). Using CST Microwave Studio, we first design rectangular MSPAs and then circular MSPAs, maintaining a 1.6 mm substrate height and using Copper (Anneal) for both the patch and ground materials. The target frequency is 5.8 GHz, relevant for 5G applications. By comparing the antenna parameters across different substrates, we aim to identify the optimal substrate and antenna design for future technology needs. © 2024 Elsevier B.V., All rights reserved.