Browsing by Author "Abd-Alhameed, Raed A."

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    Dynamic analysis model of a class E2 converter for low power wireless charging links
    (IET, 2019-01-07) Bati, Akram; Luk, Patrick Chi-Kwong; Aldhaher, Samer; See, Chan H.; Abd-Alhameed, Raed A.; Excell, Peter S.
    A dynamic response analysis model of a Class E2 converter for wireless power transfer applications is presented. The converter operates at 200 kHz and consists of an induction link with its primary coil driven by a class E inverter and the secondary coil with a voltage-driven class E synchronous rectifier. A seventh-order linear time invariant state-space model is used to obtain the eigenvalues of the system for the four modes resulting from the operation of the converter switches. A participation factor for the four modes is used to find the actual operating point dominant poles for the system response. A dynamic analysis is carried out to investigate the effect of changing the separation distance between the two coils, based on converter performance and the changes required of some circuit parameters to achieve optimum efficiency and stability. The results show good performance in terms of efficiency (90–98%) and maintenance of constant output voltage with dynamic change of capacitance in the inverter. An experiment with coils of the dimension of 53 × 43 × 6 mm3 operating at a resonance frequency of 200 kHz, was created to verify the proposed mathematical model and both were found to be in excellent agreement.
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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.