Yazar "Yalduz, Husnu" seçeneğine göre listele

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    Öğe
    An ultra-wide band low-SAR flexible metasurface-enabled antenna for WBAN applications
    (Springer Heidelberg, 2019) Yalduz, Husnu; Koc, Burak; Kuzu, Lokman; Turkmen, Mustafa
    In this study, an ultra-wideband low-specific absorption rate (SAR) flexible metasurface-enabled wearable antenna is proposed for wireless body area network applications. The antenna and metamaterial (MM) structure were designed and analyzed using a commercial electromagnetic simulation software program which uses a finite integration technique solver. The antenna is designed and fabricated on a jeans textile substrate in the size of 58 x 80 x 1 mm(3). Moreover, MM reflector was designed on a felt textile substrate to reduce the SAR effect of the antenna and to increase the antenna performance (such as impedance matching, radiation pattern, and realized gain) parameters. Designed and fabricated antenna parameters and the SAR value results with and without MM are investigated. The simulated peak SAR values when the antenna with MM is placed on the body model are 0.86, 0.198, and 0.103 W/kg at frequencies of 4 GHz, 7 GHz, and 10 GHz, respectively, for 10 g of tissue. The simulated peak SAR value of the antenna with MM is also reduced by a percentage of 97, compared to the simulated peak SAR value of the antenna without MM. The peak SAR values of the antenna were less than the European safety limit of 2 W/kg for 10 g of tissue when the MM was used as an isolator. Furthermore, the simulated peak realized gain value of the antenna with the MM was increased by 98% (from 4.6 to 9.1 dB) compared to the simulated peak realized gain value of the antenna without MM. Simulation and measurement results showed that performance characteristics and peak SAR values of the proposed antenna were suitable and safe for wearable technologies.
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    Öğe
    Design and analysis of low profile and low SAR full-textile UWB wearable antenna with metamaterial for WBAN applications
    (Elsevier Gmbh, 2020) Yalduz, Husnu; Tabaru, Timucin Emre; Kilic, Veli Tayfun; Turkmen, Mustafa
    In this paper, a low-profile wearable antenna with metamaterial (MM) for wireless body area network (WBAN) applications is presented. The designed antenna with MM operates in the ultra-wideband (UWB) between 4.55 and 13 GHz and it has a thickness of 4.68 mm. To the best of our knowledge, it is the lowest thickness reported in the literature for UWB antennas with MM. The proposed is designed and manufactured using fully flexible textiles. The designed antenna was simulated in free space and on the human body model. Simulation results show that gain, directionality, and front-to-back ratio of the antenna increase considerably with the placement of the MM. Also, in simulations, it is found that the specific absorption rate (SAR) values for the designed antenna reduce by 98.3% when MM is used. These SAR values calculated for the designed antenna with MM are well below the limits defined in European standards. The designed antenna and metamaterials were manufactured, too, and scattering parameters were measured. Measurement results are in good agreement with the results found in the simulations. It shows that the proposed antenna is very suitable for use in WBAN applications due to its low thickness, having low SAR, and UWB operation.
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    Öğe
    Dual-Band Patch Antenna with Simple Rectangular Shaped Slots for Local Area Networks
    (Springer, 2021) Turkmen, Mustafa; Gunes, Yakup Emre; Hakanoglu, Baris Gurcan; Yalduz, Husnu; Sen, Osman
    In this study, a coplanar waveguide fed patch antenna is proposed for Wireless Local Area Network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX) operations. To obtain multiband functionality and tune the frequencies rectangular shaped slots are embedded vertically and horizontally on the radiating part. The effects of the slots on the operating frequencies are analyzed in detail by performing parametric analyzes. The proposed antenna operates in a wide range covering WLAN and WiMAX frequencies between 2.38 and 5.46 GHz. To authenticate the simulation results an example model is manufactured using a 40 x 30 mm(2) FR4 dielectric substrate with the permittivity of 4.3. It has been obtained a good compatibility between the computer software results and measurment results. The measurement shows that the antenna can provide dual impedance bandwidths by having resonances at 2.74 GHz and 4.94 GHz. Consequently, the final antenna model is a good candidate to be used at the designed frequencies and one can have a clear idea how to control the resonant frequencies of the antenna for different dimension parameters of the slots.
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    Öğe
    Stub Loaded Patch Antenna and a Novel Method for Miniaturization at Sub 6 GHz 5G and Wi-Fi Frequencies
    (Univ Suceava, Fac Electrical Eng, 2021) Hakanoglu, Bans Gurcan; Koc, Burak; Sen, Osman; Yalduz, Husnu; Turkmen, Mustafa
    This paper presents both a comprehensive analysis of a stub loaded rectangular patch antenna and a novel method to achieve more compact sizes for the antenna. It has been found that with certain stub dimensions the operating frequency shifts about 24%-27% to the lower ranges and it is possible to design the antenna with more compact sizes at these shifted bands. The model antennas are designed to operate at sub 6 GHz 5G bands and 5.8 GHz Wi-Fi band. It has been shown that the method can also be used for any frequency between 1.3 GHz and 8 GHz. Detailed parametric analyses have been performed for the best results. With these modifications, it is attained a remarkable size reduction from nearly 0.32 lambda(2) to 0.16 lambda(2) which means a decrease of 50% for each antenna with almost the same or better radiation characteristics. Moreover, to explain the method clearer a flow chart is given for the design procedure and to gain more confidence for our simulation results a prototype for 2.4 GHz is fabricated and measured. It has been proven that experimental measurements and simulation results are in good agreement.