Browsing by Author "Kamarudin, Muhammad Ramlee"

Now showing 1 - 4 of 4
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    Complementary split ring resonator for isolation enhancement in 5G communication antenna array
    (Electromagnetics Academy, 2018-04-24) Selvaraju, R.; Jamaluddin, M. H.; Kamarudin, Muhammad Ramlee; Nasir, J.; Dahri, M. H.
    A square-shaped complementary split ring resonator (CSRR) filtering structure for isolation improvement is presented in this paper. The proposed research work investigates the design and development of a simple and compact CSRR structure. In order to verify the performance of the proposed filtering element and improve the isolation among the closely placed antenna elements, arrays of configured CSRR structures are implemented between two antenna elements. An array of configured CSRR elements has been integrated with the printed antenna on the top and bottom layers. The proposed filtering elements offer an enhancement in isolation by 25 dB as compared to the simple array. The entire configuration has been simulated using the Ansoft HFSS simulator. Finally, the proposed design is fabricated and experimentally validated. In the experiment, coupling suppression of -51 dB at the operating frequency is successfully achieved, resulting in a recovery of the array pattern. The proposed antenna is highly efficient, which is suitable to be utilized for 5G communication.
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    Highly efficient wearable CPW antenna enabled by EBG-FSS structure for medical body area network applications
    (IEEE, 2018-11-26) Ashyap, Adel Y. I.; Abidin, Zuhairiah Zainal; Dahlan, Samsul Haimi; Majid, Huda A.; Kamarudin, Muhammad Ramlee; Alomainy, Akram; Abd-Alhameed, Raed A.; Kosha, Jamal Sulieman; Noras, James M.
    A wearable fabric CPW antenna is presented for medical body area network (MBAN) applications at 2.4 GHz based on an electromagnetic bandgap design and frequency selective surface (EBG-FSS). Without EBG-FSS, the basic antenna has an omnidirectional radiation pattern, and when operated close to human tissue, the performance and efficiency degrade, and there is a high specific absorption rate. To overcome this problem, the antenna incorporates EBG-FSS, which reduces the backward radiation, with SAR reduced by 95%. The gain is improved to 6.55 dBi and the front-to-back ratio is enhanced by 13 dB compared to the basic antenna. The overall dimensions of the integrated design are 60×60×2.4 mm 3 . Simulation and experimental studies reveal that the antenna integrated with EBG-FSS can tolerate loading by human tissue as well as bending. Thus, the design is a good candidate for MBAN applications.
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    Radiation pattern performance of unequally linear arrays with parasitic element
    (Institute of Advanced Engineering and Science, 2017-04-01) Zaina, Noor Ainniesafina; Kamarudin, Muhammad Ramlee; Yamada,Yoshihide; Seman, Norhudah
    For next generation of 5G mobile base station antennas, multibeam, multifrequency and low sidelobe characteristics requested. Simplify the feeding network will contribute a low feeder loss and frequency dependent. From the previous research by the author, low sidelobe level reported by density tapered array configuration from -13 dB to -16 dB and the result maintained for wideband operation frequency at 28 GHz, 42 GHz, and 56 GHz. However, the grating lobe has occurred due to element spacing larger than a wavelength of higher frequency (56 GHz). In this paper, an investigation was made of the performance of radiation pattern for unequally microstrip linear array antenna in frequency 42 GHz and 56 GHz by loading parasitic elements. The effect of parasitic element to the impedance, gain, and sidelobe level of unequally microstrip linear spaced tapered array also examined. The design has been simulated using Ansoft High Frequency Structural Simulator (HFSS) ver 16.0.
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    User influence on mobile terminal antennas: a review of challenges and potential solution for 5G antennas
    (IEEE, 2018-11-28) Khan, Rizwan; Al-Hadi, Azremi Abdullah; Soh, Ping; Kamarudin, Muhammad Ramlee
    This paper presents a comprehensive review of mobile terminal antenna researches performed in the past seven years and the current challenges related to the user’s influence on the performance of fifth generation (5G) terminal antennas. The main challenges for the designing of mobile terminal antennas are to meet the compact size requirements of built-in structures and their multiband capabilities. The antenna design techniques that are used to achieve broader operating bandwidths with smaller antenna dimensions will be first discussed. This is followed by the effects of user interactions with the head/hand for mobile antennas in terms of radiation efficiency and, consequently, the correlation of multiple input multiple output (MIMO) antenna systems. The ultimate aims of this paper are as follows: 1) to highlight the different frequencies of mobile terminal antennas for different applications; 2) to highlight mobile terminal antennas that have been developed for 5G application; 3) to study and discuss the effects of user’s hand on 5G mobile terminal antennas; and 4) to discuss the research gap, issues, and challenges in the field of user’s effects on mobile terminal antennas for 5G applications. In addition to that, an investigation of the users’ hand effects on two MIMO mobile terminal antennas operational in the sub-6-GHz 5G band is presented. This investigation performed using two MIMO antennas is an attempt to formulate guidelines on efficient mobile terminal antenna design in the presence of user’s hand in C Band (from 3.4 to 3.6 GHz) and LTE-U Band 46 (from 5.15 to 5.925 GHz).