Yazar "Abdullah, Mujeeb" seçeneğine göre listele
Listeleniyor 1 - 5 / 5
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe A novel high GainWideband MIMO antenna for 5G millimeter wave applications(MDPI, 2020) Sehrai, Daniyal Ali; Abdullah, Mujeeb; Altaf, Ahsan; Kiani, Saad Hassan; Muhammad, Fazal; Tufail, Muhammad; Irfan, Muhammad; Glowacz, Adam; Rahman, SaifurA compact tree shape planar quad element Multiple Input Multiple Output (MIMO) antenna bearing a wide bandwidth for 5G communication operating in the millimeter-wave spectrum is proposed. The radiating element of the proposed design contains four different arcs to achieve the wide bandwidth response. Each radiating element is backed by a 1.57 mm thicker Rogers-5880 substrate material, having a loss tangent and relative dielectric constant of 0.0009 and 2.2, respectively. The measured impedance bandwidth of the proposed quad element MIMO antenna system based on 10 dB criterion is from 23 GHz to 40 GHz with a port isolation of greater than 20 dB. The measured radiation patterns are presented at 28 GHz, 33 GHz and 38 GHz with a maximum total gain of 10.58, 8.87 and 11.45 dB, respectively. The high gain of the proposed antenna further helps to overcome the atmospheric attenuations faced by the higher frequencies. In addition, the measured total efficiency of the proposed MIMO antenna is observed above 70% for the millimeter wave frequencies. Furthermore, the MIMO key performance metrics such as Mean Effective Gain (MEG) and Envelope Correlation Coefficient (ECC) are analyzed and found to conform to the required standard of MEG < 3 dB and ECC < 0.5. A prototype of the proposed quad element MIMO antenna system is fabricated and measured. The experimental results validate the simulation design process conducted with Computer Simulation Technology (CST) software.Öğe Eight element side edged framed MIMO antenna array for future 5G smart phones(MDPI, 2020) Kiani, Saad Hassan; Altaf, Ahsan; Abdullah, Mujeeb; Muhammad, Fazal; Shoaib, Nosherwan; Anjum, Muhammad Rizwan; Damasevicius, Robertas; Blazauskas, TomasThis paper presents a novel design of a Multiple Input Multiple Output (MIMO) antenna system for next generation sub 6 GHz 5G and beyond mobile terminals. The proposed system is composed of a main board and two side boards. To make the design cost-effective, FR4 is used as a substrate. The design is based on a unit monopole antenna etched at the side substrate. The single element is resonating at 3.5 GHz attaining a 10 dB bandwidth of 200 MHz and a 6 dB bandwidth of 400 MHz. The single element is then transformed into an MIMO array of 8-elements with an overall dimension of 150 mm x 75 mm x 7 mm, providing pattern diversity characteristics and isolation better than -12 dB for any two radiating elements. A number of studies such as effects of human hand on the system that includes single hand mode and dual mode scenarios and the effects of Liquid Crystal Display (LCD) over the principal performance parameters of the system are presented. The envelop correlation coefficient (ECC) is computed for all the scenarios and it is found that ECC is less than 0.1 for any case and maximum channel capacity is 38.5 bps/Hz within the band of interest. The main advantage of the proposed design over available designs in the literature is that almost all of the main substrate is empty providing wide space for different sensors, systems, and mobile technology components. A brief literature comparison of the proposed system is also presented. To validate the proposed model, a prototype is fabricated and results are presented. This design can be applied on higher frequencies to future micromachines for on chip communications using same theocratical approach as the space for higher frequencies in mmwave spectrum has been reserved. The simulated results are in an excellent agreement with the measured results. All the main performance parameters of the design are calculated and compared with the measured results wherever possible.Öğe Future smartphone: MIMO antenna system for 5G mobile terminals(IEEE-Institute of Electrical and Electronics Engineers Inc., 2021) Abdullah, Mujeeb; Altaf, Ahsan; Anjum, Muhammad Rizwan; Arain, Zulfiqar Ali; Jamali, Abdul Aleem; Alibakhshikenari, Mohammad; Falcone, Francisco; Limiti, ErnestoIn this article, an inverted L-shaped monopole eight elements Multiple Input Multiple Output (MIMO) antenna system is presented. The multi-antenna system is designed on a low cost 0.8 mm thick FR4 substrate having dimensions of 136 x 68 mm(2) resonating at 3.5GHz with a 6dB measured bandwidth of 450MHz, and with inter element isolation greater than 15 dB and gain of 4 dBi. The proposed design consists of eight inverted L-shaped elements and parasitic L-shaped strips extending from the ground plane. These shorted stripes acted as tuning stubs for the four inverted L-shaped monopole elements on the side of chassis. This is done to achieve the desired frequency range by increasing the electrical length of the antennas. A prototype is fabricated, and the experimental results show good impedance matching with reasonable measured isolation within the desired frequency range. The MIMO performances, such as envelope correlation coefficient (ECC) and mean effective gain (MEG) are also calculated along with the channel capacity of 38.1bps/Hz approximately 2.6 times that of 4 x 4 MIMO system. Due to its simple shape and slim design, it may be a potential chassis for future handsets. Therefore, user hand scenarios, i.e. both single and dual hand are studied. Also, the effects of hand scenarios on various MIMO parameters are discussed along with the SAR. The performance of the proposed system in different scenarios suggests that the proposed structure holds promising future within the next generation radio smart phones.Öğe Modified U-shaped resonator as decoupling structure in MIMO antenna(MDPI, 2020) Iqbal, Amjad; Altaf, Ahsan; Abdullah, Mujeeb; Alibakhshikenari, Mohammad; Limiti, Ernesto; Kim, SunghwanThis paper presents an isolation enhancement of two closely packed multiple-input multiple-output (MIMO) antenna system using a modified U-shaped resonator. The modified U-shaped resonator is placed between two closely packed radiating elements resonating at 5.4 GHz with an edge to edge separation distance of 5.82 mm (lambda(degrees)/10). Through careful adjustment of parametric modelling, the isolation level of -23 dB among the densely packed elements is achieved. The coupling behaviour of the MIMO elements is analysed by accurately designing the equivalent circuit model in each step. The antenna performance is realized in the presence and absence of decoupling structure, and the results shows negligible effects on the antenna performance apart from mutual coupling. The simple assembly of the proposed modified U-shaped isolating structure makes it useful for several linked applications. The proposed decoupling structure is compact in nature, suppress the undesirable coupling generated by surface wave and nearby fields, and is easy to fabricate.Öğe Nature inspired MIMO antenna system for future mmWave technologies(MDPI, 2020) Rahman, Saifur; Ren, Xin-cheng; Altaf, Ahsan; İrfan, Muhammad; Abdullah, Mujeeb; Muhammad, Fazal; Anjum, Muhammad Rizwan; Mursal, Salim Nasar Faraj; AlKahtani, Fahad SalemIn this work, a new Multiple Input Multiple Output (MIMO) antenna system with a novel shape inspired by nature is proposed for Fifth-Generation (5G) communication systems. The antenna is designed on a Rogers 5880. The dielectric constant of the substrate is 2.2, and the loss tangent is assumed to be 0.0009. The gain of the system for the desired bandwidth is nearly 8 dB. The simulated and the measured efficiency of the proposed system is 95% and 80%, respectively. To demonstrate the capability of the system as a potential candidate for future 5G communication devices, MIMO key performance parameters such as the Envelope Correlation Coefficient (ECC) and Diversity Gain (DG) are computed. It is found that the proposed system has low ECC, constant DG, and high efficiency for the desired bandwidth.
