A faculty member in the Department of Electronic and Communications Engineering (Assist. Prof. Dr. Dhirgham Kamal Naji) participated in the membership of the discussion committee for the doctoral student (Maryam Qutaiba Abdel Razzaq) from Al-Nahrain University - College of Information Engineering, which took place on Thursday, 07/04/2024.” About her thesis titled:

Equalizer Based Squinting Beam Effects Removal from Planar Array Antennas for 5G Communications

The discussion committee consisted of distinguished professors:

Prof. Dr. Malik Jassim Farhan / College of Engineering / Al-Mustansiriya University / Chairman

Prof. Dr. Anas Ali Hussein / Al-Nahrain University / Al-Nahrain Research Center for Renewable Energy / Member.

Assist. Prof Dr. Dhirgham Kamal Naji / Al-Nahrain University / College of Engineering / Member

Assist. Prof Dr. Taha Ahmed Aliwi / Al-Nahrain University / Ministry of Higher Education and Scientific Research / Member.

Assist. Prof Dr. Ammar Abdul Malik Abdul Karim / Al-Nahrain University / College of Information Engineering / Member.

Assist. Prof. Dr. Asmaa Hamid Majeed / Al-Nahrain University / College of Information Engineering / Member and First Supervisor

Prof. Dr. Raed Abdel Hamid Abdel Majeed / University of Bradford / United Kingdom / member and second supervisor

The student fulfilled the requirements for obtaining a doctoral degree with a very good grade

The dissertation dealt with an in-depth analysis of the effect of “beam diffraction” in millimeter wave antenna assemblies, including its mechanisms and effects. Initially, a square-shaped antenna was designed for high-frequency millimeter wave communications at 26.2 gigahertz with a bandwidth of 2 gigahertz using the CST program. The design was then expanded into linear and planar configurations to measure the value of mutual entanglement between the antenna elements in relation to their separation distance. The use of antenna combinations resulted in an increase in antenna gain to 16.2 dBi for ULA and 25.8 dBi for UPA.

The nature of the beam deflection was then investigated, and a suitable model was developed for both ULA and UPA groups. This was followed by a simulation using MATLAB to evaluate the effect of beam deviation on channel performance. Quadrature Phase Shift Keying, M-ary Phase Shift Keying, and M-ary Quadrature Amplitude Modulation were used to complete the comprehensive analysis.

Extensive simulation results indicate that beam diffraction in millimeter wave communications reduces channel capacity by 15% at 40 dB power-to-noise ratio (Eb/No), and potentially increases data error rates. Finally, strategies based on compensation methods are proposed to mitigate the beam diffraction phenomenon and improve system performance. Linear compensation correctors, such as Zero Forcing, Minimum Mean Square Error, are first used to eliminate beam aberration by treating the antenna array as a frequency-selective channel. Then a new type of compensation corrector was developed that uses neural networks, and the performance of the three correctors was tested under different working conditions of the system. The results emphasized the importance of dealing with beam deviation as a potential problem affecting the performance of fifth generation systems and highlighted the possibility of treatment using artificial intelligence as an effective solution.