Browsing by Author "Nasir, J."

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    A compact frequency reconfigurable hybrid DRA for LTE/Wimax applications
    (Hindawi Publishing, 2017-09-25) Aqeel, S.; Kamarudin, M. R.; Khan, A. A.; Saleem, J.; Nasir, J.; Kazim, J. R.; Owais, O.
    A compact hybrid antenna structure with frequency reconfiguration capabilities is presented in this article. The proposed design employs a combination of a rectangular DR element and a coupling slot on the structure’s ground plane (GP). The slot shifts the fundamental DRA mode by introducing a slow wave effect and its resonant behavior helps to achieve an omni-directional pattern at low frequencies. The slot is loaded with a series of PIN diode switches whose ON/OFF combinations alter the effective slot length. Slot loading with PIN diodes results in frequency reconfiguration of the proposed structure with a large tuning range of 76.2 % (between 1.73 to 3.86 GHz). A parametric analysis was performed to investigate the effects of slot length, width and position on the reflection coefficients of the proposed structure. A prototype of the proposed design was fabricated and results were measured. The measured results show a close agreement with the simulated ones. The proposed design is suitable for DCS 1800 MHz, PCS 1900 MHZ, UMTS, LTE 2500-2700 MHz, and Wimax 3.5 GHz.
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    ItemOpen Access
    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.