Browsing by Author "Daw, Ahmed Fawzy"

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Four ports MIMO printed antenna with high isolation for UWB and X-band systems
(Cambridge University Press, 2023-11) Ibrahim, Ahmed A; Eltokhy, Amira; Daw, Ahmed Fawzy
In this work, a compact size 4 ports multiple input multiple output (MIMO) slot antenna with the connected ground for Ultra-Wide Band (UWB) and X band applications is introduced and discussed. The single antenna is a cross-shaped slot antenna in the ground plane and a 50 Ω microstrip line with a small L-stub is used to feed the antenna on the other side. The suggested MIMO antenna has four identical elements arranged to be orthogonal to each other to enhance the MIMO system performance. The antenna elements are connected with a small strip to compose the proposed connected ground antennas. The suggested MIMO antenna has an overall size of 47 mm × 47 mm. The antenna has tested and simulated bandwidth with S11 < −10 dB extended from 4– 14 GHz and has isolation greater than 20 dB between ports without utilizing the decoupling elements and with good consistency between results. The MIMO antenna has peak gain and efficiency, envelope correlation coefficient, diversity gain, and channel capacity loss of 5.6 dBi and 80%, <5 × 10–3, 10 dB, and <0.4 bit/s/Hz, respectively which prove that our antenna can be suggested for the UWB MIMO applications.
Novel Compact Reconfigurable Metamaterial Diplexer-Based on RF Switches for Wireless Applications
(Semarak Ilmu Publishing, 2025-02) Tolba, Youssef Khaled; Daw, Ahmed Fawzy; Esia, Saleh Mohamed
This paper proposes a novel reconfigurable diplexer design based on metamaterial DCRLH transformer. The D-CRLH concept provides duality in the overall response of the diplexer achieving several bands and reducing the overall size of the diplexer, the novel reconfigurable diplexer size is 39x15mm!. The system achieves reconfigurability by utilizing a PIN-diode RF switching circuit in the D-CRLH load line, allowing for seamless connection and disconnection using a biasing circuit. The novel reconfigurable diplexer offers a wide band of operation of 1GHz to 4GHz with notches to cantered at bands 1.8GHz and 2.6GHz with both notches having suppression band of 300MHz. The reconfigurable diplexer covers commercially used wireless bands, making it suitable for diverse wireless communication applications.
A Novel of Metamaterial Ultra Compact Reconfigurable Phase Shifter Based on Dual Composite Right Left Handed Structure (D-CRLH)
(EMW Publishing, 2024-01) Farag, Yasser Sobhy; Abaza, Mohamed; Daw, Ahmed Fawzy
A novel ultra-compact dual-band reconfigurable microstrip phase shifter designed by using a dual-composite right/left handed D-CRLH technique of metamaterial is introduced. The paper proposes detailed studies between the simulation and the fabricated prototype results. Moreover, the study of the proposed phase shifter explains a shifting range from 0◦ till 360◦ by submitting four mounted surface switches in different spots of the fingers. Switches have fixed states shifting to provide the controlling of the requested range. The switches were chosen to be from PIN Diode as it has many compatible characteristics which are explained in the proposed paper. The reconfigurable phase shifter designed with high quality factors and low insertion loss 0.25 and 0.2 at 5.7 GHz and 7.5 GHz respectively with a very compact size area 8 × 11. The proposed shifter supports the application of wide band usage especially for network access point, Wi-Fi, WiMAX network, and wireless LAN connections in addition to the application of point to point microwave radio links and X-band of satellite & space communications.