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This paper presents a new periodic grooved dielectric leaky-wave antenna with non-identical irregularities for an extremely high-frequency range capable of performing efficiently in the Ka band through a stable gain, a decrease in the level of the side lobes, and the achievement of a narrower main lobe beam. It consists of a dielectric waveguide antenna placed inside a channelled rectangular metallic waveguide to improve performance. A dielectric rod was used to overcome the losses related to the propagation of electromagnetic waves in metal conductors. A grooved dielectric of a 21-element linear array is used to propose a simple approach for the synthesis of such antennas based on a modified energy method and is fed by a standard waveguide. It was designed and simulated at 37.2 GHz for satellite, 5G antenna, and radar applications. The major novelty of this study is the ability to control the direction of the main lobe through non-identical irregularities in geometric parameters such as the width, height, and distance between each element. Radiation techniques have been extensively studied using simulations. A performance antenna with radiation efficiency of 99.35%, gain of 22 dBi, width of radiation pattern of 3.2 $$^{\circ }$$ ∘ , and side lobe level (SLL) of $${-}$$ -  18.3 dB has been achieved.

This research paper aims to present an integrated evaluation model in e-learning systems for students. The paper describes the phases of development and analysis of the application of a web-based open student evaluation model in an e-Learning System. The proposed model has been tested and evaluated in terms of its effectiveness on student communication, collaboration, and progress. The evaluation has showed that the proposed model provides the students with flexible mechanism to control access to their model information.

This paper presents a new periodic grooved dielectric leaky-wave antenna (LWA) with non-identical irregularities for an extremely high-frequency (EHF) range capable of performing efficiently in the Ka band through a stable gain, a decrease in the level of the side lobes, and the achievement of a narrower main lobe beam. It consists of a dielectric waveguide antenna placed inside a channeled rectangular metallic waveguide to improve performance. A dielectric rod was used to overcome the losses related to the propagation of electromagnetic waves in metal conductors. A grooved dielectric of a 21-element linear array is used to propose a simple approach for the synthesis of such antennas based on a modified energy method and is fed by a standard waveguide. It was designed and simulated at 37.2 GHz for satellite, 5G antennas, and radar applications. The major novelty of this study is the ability to control the direction of the main lobe through non-identical irregularities in geometric parameters, such as the width, height, and distance between each element. Radiation techniques have been studied extensively using simulations. A performance antenna with radiation efficiency 99.35%, gain 22 dBi, width of radiation pattern 3.2 ◦ , and side lobe level (SLL) -18.3 dB has been achieved.

This paper addresses the issue of constructing millimeter band antennas using dielectric waveguide structures. A new type of linear antenna, incorporating metal pins on the side walls of the grooved dielectric waveguide, is proposed for generating polarization perpendicular to the waveguide axis. However, these antennas suffer from the drawback of cross-polarized radiation in directions close to the waveguide axis. To overcome this limitation, a modified antenna design with transverse polarization is introduced, featuring a closed groove waveguide with a longitudinal slot in the top of wall. The paper provides a comparison between two types of dielectric waveguide antennas. First, waveguide antenna with grooves in the dielectric which resulting longitudinal polarization, and second, waveguide antenna with quarter-wavelength pins which resulting transverse polarization. Electrodynamic modeling data is provided to demonstrate the effectiveness of the proposed antennas for satellite, 5G antenna, and radar applications. Finally, antenna of quarter-wavelength pins is proposed with frequency of 39GHz, gain of 19.8dBi, width of radiation pattern of 3.2\(^{\circ}\) and side lobe level (SLL) of -13.3dB has been achieved.