Hadia M. El-Hennawy

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This paper presents two applications of the coupled-line composite right/left-handed (CL-CRLH) unit cell, compact-size rat-race hybrid, and arbitrary coupling directional coupler. Benefiting from the slow-wave effect present in both the right- and left-handed regions of the CL-CRLH unit cell, two compact-size rat-race hybrids were realized. 60% area(More)
In this paper, an advanced closed loop polarized Multiple-Input Multiple-Output antenna system employing Pre-RAKE and Combined Transmit Diversity techniques “Polarized MIMO Pre-RAKE CTD system” is proposed in Frequency Division Duplex (FDD) mode. The proposed system introduces a significant performance gain without increasing the complexity and the power(More)
This paper evaluates the performance of the Selection Transmit Diversity (STD) technique in adaptive Polarized Multiple-Input Multiple-Output (MIMO) Pre-RAKE system. The proposed system will be examined in Frequency Division Duplex (FDD) mode. For the same spatial dimensions, the proposed system will be compared with the Pre/Post RAKE systems and the(More)
in this paper, a Space-Time-Frequency block code (STFBC) based on Quasi-Orthogonal designs is proposed over a frequency selective Rayleigh fading channel. The proposed code achieves rate-one and full diversity offered by the MIMO-OFDM channel. For quasi-static channel over adjacent OFDM symbol durations, as numerical results demonstrate, the proposed code(More)
A theoretical investigation of space-charge plane-wave interaction at dielectric-semiconductor interfaces is presented. A full-wave and charge transport formulation is applied to the analysis of the fundamental mode of propagation in a semiconductor substrate backed with a ground plane. Closed-form expressions for the field components, charge carrier(More)
This paper presents a novel quad-band power divider with equal power division ratio. The proposed power divider is realized using two cascaded sections of dual-band transformers based on coupled microstrip lines. Limitations of using dual-band quarterwavelength transformers based on coupled lines are studied through parametric analysis to obtain useful(More)
The Internet of Things (IoT) aims to connect the growing number of sensing and monitoring devices to humans or other devices with the goal of exchanging data or controlling these devices. IoT can be considered as the set of technologies that allow small devices e.g. sensors, which constitute wireless sensor networks (WSNs) that perform specific tasks, to(More)
Spectrum sensing technique is the most crucial factor that determines the performance of Cognitive Radio (CR) systems. Wideband spectrum sensing using Nyquist and sub Nyquist sampling rates proved to have better performance than other types of spectrum sensing. Multi-rate spectrum sensing technique have advantage over other wideband spectrum sensing(More)
In this paper, an advanced closed loop PolarizedMultiple-InputMultiple-Output Pre-RAKE Combined Transmit Diversity “Pol MIMO Pre-RAKE CTD” system is proposed for the downlink. The proposed system is designed and analyzed in frequency division duplex mode. The numerical results demonstrate that it can achieve a significant performance gain, especially for(More)
Recently in cooperative spectrum sensing, there are many researches on designing strategies for the optimization of the length of the sensing time (as a part of the total frame length) while fulfilling the objective of achieving certain level of protection of primary users. The performance of cooperative spectrum sensing scheme is greatly affected by the(More)