Browsing by Author "Helala, M.A."

Now showing 1 - 3 of 3

Citation - Scopus: 1
Beamforming Network for 5g Applications
(Institute of Electrical and Electronics Engineers Inc., 2023) Raafat, M.A.; Allam, A.M.M.A.; Helala, M.A.; Ghanem, M.G.; Fawzy, Diaa E.; Abbas, M.A.; Abo, Sree, M.F.
This paper is devoted to the design, analysis, and implementation of switched beamforming network operating at 5.2 GHz for 5G applications. It is intended to launch four beams. The Butler matrix feeding network is presented to electronically switch the beam in the desired direction. This work achieves a good approach to alleviate the problem of cross-over implementation and fabrication. A Four-element array of printed antennas is designed and fabricated. The network and array are implemented on Rogers RT/duroid 5880 substrate with a relative permittivity of 2.2 and a thickness of 1.04 mm. The different scattering parameters are simulated using both ADS and CST which conduct good agreement between the simulated and measured results. © 2023 IEEE.
Citation - Scopus: 2
A Multi-Band Textile-Based Mtm Absorber for Energy Harvesting Applications
(Institute of Electrical and Electronics Engineers Inc., 2023) Allam, A.M.M.A.; Helala, M.A.; Fawzy, Diaa E.; Abbas, M.A.; Sree, M.F.A.; Parchin, N.O.; Amar, A.S.I.
This paper is devoted to design and implementation of multi-band textile based Metamaterial absorber operating at K and Ku bands to be deployed in energy harvesting system. The unit cell of the absorber comprises a ground plane of copper annealed, Felt textile and top ground layer with etched Jerusalem cross surrounded with etched square ring. It provides three highly resonant peaks at 16.7 GHz, 18.6GHz, and 22.45 GHz, with absorption percentages of 99.8%, 96.5%, and 99.7%, respectively. The full width at half maximum (FWHM) is 3.35 GHz (19%) at 17.6 GHz. In addition, the absorber provides a wideband of absorption for oblique incidence up to 20 degrees and also at different bending radii. The relative permittivity and permeability are studied to demonstrate it effect on the absorption mechanism. A negative index of refraction is achieved over a band of 6.5 GHz from 16 GHz to 22.5 GHz, which leads to perfect absorptivity. © 2023 IEEE.
Citation - Scopus: 1
An Ultra-Wideband Textile-Based Perfect Superstrate Metamaterial Absorber for 6g Applications
(Institute of Electrical and Electronics Engineers Inc., 2023) Allam, A.M.M.A.; Helala, M.A.; Ghanem, M.G.; Raafat, M.A.; Fawzy, Diaa E.; Akarsu, Gokberk; Abbas, M.A.
This paper presents an ultra-wideband textile-based perfect Metamaterial absorber for 6G applications. The design geometry of the unit cell is based on a modified split ring resonator and optimized akin to the word 6G. It enables a wideband in sub-THz at the standard of FCC. The structure consists of three layers; the ground layer, the textile layer, and MTM resonators. The two resonators are 6G and L shaped. The structure is optimized in terms of the different dimensions of both resonators. For more enhancement of the absorptivity band, superstrate textile material is added on top of the resonator's structure. It enhances the band by 6 %. The structure is subjected to different angles of incidence to study the sensitivity of the absorber to that angle. It contributes a bandwidth of 17.135 GHz up to 30 degrees and an FWHM of more than 33.332 GHz up to 45 degrees. The textile material used is felt having a permittivity of 1.27, thickness of 0.6 mm, and tangent loss of 0.016. The overall size of the absorber is 2.4 mm x 2.4 mm x 1.27 mm. © 2023 IEEE.