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    A four element mm-wave MIMO antenna system with wide-band and high isolation characteristics for 5G applications
    (MDPI, 2023) Munir, Mehr E.; Kiani, Saad Hassan; Savcı, Hüseyin Şerif; Marey, Mohamed; Khan, Jehanzeb; Mostafa, Hala; Parchin, Naser Ojaroudi
    In this article, we propose a light weight, low profile Multiple Input Multiple Output (MIMO) antenna system for compact 5th Generation (5G) mmwave devices. Using a RO5880 substrate that is incredibly thin, the suggested antenna is made up of circular rings stacked vertically and horizontally on top of one another. The single element antenna board has dimensions of 12 × 12 × 0.254 mm (Formula presented.) while the size of the radiating element is 6 × 2 × 0.254 mm (Formula presented.) (0.56 (Formula presented.) (Formula presented.) × 0.19 (Formula presented.) (Formula presented.) × 0.02 (Formula presented.) (Formula presented.)). The proposed antenna showed dual band characteristics. The first resonance showed a bandwidth of 10 GHz with a starting frequency of 23 GHz to an ending frequency point of 33 GHz followed by a second resonance bandwidth of 3.25 GHz ranging from 37.75 to 41 GHz, respectively. The proposed antenna is transformed into a four element Linear array system with size of 48 × 12 × 0.254 mm (Formula presented.) (4.48 (Formula presented.) (Formula presented.) × 1.12 (Formula presented.) (Formula presented.) × 0.02 (Formula presented.) (Formula presented.)). The isolation levels at both resonance bands were noted to be >20 dB which shows high levels of isolation among radiating elements. The MIMO parameters such as Envelope Correlation Co-efficient (ECC), Mean Effective Gain (MEG) and Diversity Gain (DG) were derived and were found to be in satisfactory limits. The proposed MIMO system model is fabricated and through validation and testing of the prototype, the results were found to be in good agreement with simulations.
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    Eight element MIMO antenna array with tri-band response for modern smartphones
    (Institute of Electrical and Electronics Engineers Inc., 2023) Kiani, Saad Hassan; Savcı, Hüseyin Şerif; Abubakar, Hassan Sani; Parchin, Naser Ojaroudi; Rimli, Hatem; Hakim, Bandar
    This article presents an eight-element tri-band Multiple Input Multiple Output (MIMO) antenna system for future handheld devices. The suggested antenna system consists of a main and sideboards. The feed lines are connected on the main board while the antennas are placed on sideboards, two on each side separately. The total dimension of the main board is $150\times 75$ mm2, and the sideboard is $150\times 7$ mm2. The antenna resonates at three distinct 5G allocated bands of 3.1-3.7 GHz, 4.47-4.91 GHz, and 5.5-6.0 GHz with impedance bandwidths of 600 MHz, 440 MHz, and 450 MHz, respectively. The antenna system provides pattern and spatial diversity characteristics with radiation and total efficiency of 78% and 62% and peak gain of 5.8 dBi. The MIMO system is fabricated, and the measured results are found to be in good agreement with the simulations. The isolation among radiating elements in all resonating bands is found to be >16 dB. The vital MIMO performance parameters such as envelope correlation coefficient (ECC) is less than 0.2 for any two antenna array meeting the required standard of less than 0.5 alongside the mean effective gain or MEG ratio of any two antenna meeting the required standard of less than 3 dB for power balance and optimal diversity. The Channel Capacity (CC) is found to be 41.1 bps/Hz, approximately 3 times that of $2\times $ 2 MIMO operations.
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    mmWave polarization diversity wideband multiple-input/multiple-output antenna system with symmetrical geometry for future compact devices
    (MDPI, 2023) Münir, Mehr E.; Kiani, Saad Hassan; Savcı, Hüseyin Şerif; Sehrai, Daniyal Ali; Muhammad, Fazal; Ali, Ayyaz; Mostafa, Hala; Parchin, Naser Ojaroudi
    The fifth generation (5G) of mobile networks is a significant technological advancement in telecommunications that provides faster data speeds, lower latency, and greater network capacity. One of the key technologies that enables 5G is multiple-input/multiple-output (MIMO) antenna systems, which allow for the transmission and reception of multiple data streams simultaneously, improving network performance and efficiency. MIMO is essential to meeting the demand for higher data rates and improved network performance in 5G networks. This work presents a four-element MIMO antenna system dedicated to the upper 5G millimeter-wave (mmWave) spectrum. The suggested antenna system is designed using an ultra-thin RO5880 substrate having total dimensions of 20 x 20 x 0.254 mm(3) with symmetrical geometry. The proposed antenna covers a fractional bandwidth of 46.875% (25-38 GHz), covering potential 5G bands of 26, 28, and 32 GHz, and offers isolation of >18 dB. The proposed MIMO system is fabricated and tested in-house. The antenna showed efficiency >88% at the potential band of interest and a peak gain of 3.5 dBi. The orthogonal arrangement of the resonating elements provides polarization diversity. Also, the MIMO parameters obtained, such as mean effective gain (MEG), envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), and total active reflection coefficient (TARC), are found to have good performance. The measured results obtained are found to be in good agreement with simulations, hence making the proposed MIMO antenna suitable for handheld mmWave 5G devices.
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    Performance enhancement of Vivaldi-shaped planar UWB antenna using a single-layer FSS reflector
    (2024) Kiani, Saad Hassan; Rafique, Umair; Savcı, Hüseyin Şerif; Rmili, Hatem; Parchin, Naser Ojaroudi; Algarni, Abeer D.; Elmannai, Hela
    This work proposes the design of a frequency-selective surface (FSS)-based planar monopole antenna for ultra-wideband (UWB) communication applications. The UWB response is observed by integrating a Vivaldi-shaped slot and by introducing a stepped-like pattern on the bottom edges of the radiating patch, while the back side is composed of a partial ground plane. This configuration results in a broad impedance bandwidth spanning from 3.11 to 20 GHz. For radiation performance enhancement of the proposed antenna, a single-layer UWB FSS reflector is placed beneath the antenna element at an optimized distance. The proposed FSS reflector employs a 3 × 3 array of fractal structure with a unit cell size of 12.25 × 12.25 mm2. The designed FSS reflector exhibits a linear phase response over a frequency range of 3.28 to 14 GHz, with a stop-band transmission coefficient less than -10 dB. The incorporation of the FSS reflector results in an increased gain, elevating it from 1 to 4 dBi at low-band frequencies, while at mid-band frequencies, the gain is increased from 1 to 6 dBi. The structural configuration of the proposed antenna yields directional far-field patterns, making it well-suited for UWB radar applications.
  • Küçük Resim Yok
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    Tri-band MIMO diversity antenna for modern smartphones
    (Institute of Electrical and Electronics Engineers Inc., 2023) Kiani, Saad Hassan; Savcı, Hüseyin Şerif; Rafique, Umair; Parchin, Naser Ojaroudi; Dalal, Priyanka; Abbas, Syed Muzahir
    This paper proposes the design of a MIMO antenna system with four elements, specifically tailored for future smartphones. The MIMO antenna system is operating in three important 5G frequency bands: 3.5 GHz, 4.7 GHz, and 5.8 GHz. The MIMO system utilizes a single hybrid H-shaped patch radiator as the radiating element, which is integrated into the smartphone's side-edge frame. The main board of the device consists of the feeding lines. By employing this configuration, the antenna achieves a tri-band response, satisfying the -6 dB impedance bandwidth criteria for each desired frequency band, providing bandwidths of 680 MHz, 440 MHz, and 470 MHz, respectively. The MIMO antenna system also demonstrates notable performance characteristics, including a peak gain of 5.8 dBi, a radiation efficiency of 70%, and a total efficiency of 80%. The strategic placement of antenna elements at the corners of the side-edge frames ensures isolation of greater than 16 dB between the elements in the relevant frequency bands. Furthermore, this antenna design facilitates both spatial and pattern diversity, enhancing the overall performance of the MIMO system.