Jabir Salman Aziz
@ruc.edu.iq
Computer Communication Engineering Department
Al Rafidain University college
Prof. Dr. Jabir S. Aziz received the B.Sc. degree in Electrical Engineering from MTC – Baghdad – Iraq in 1977, Ph. D. in Communication Engineering ENSAE – Toulouse – France in 1982. He has supervised more than 45 M.Sc. and Ph.D. thesis and published more than 60 peer-reviewed research papers in national and international conferences and journals. He served as an Editor-in-chief, Managing Editor and Editorial Board Member in many Scientific Journals. He participated in many international conferences as member of organizing committee and TPC member. He is currently a Professor in Microwave and Wireless Communications in Al-Rafidain University College. His research interests are: Communications systems, antenna and propagation, RF and microwave, and wireless communications.
EDUCATION
- Ph.D. in Communication Engineering from ENSAE - Toulouse - France
- Emeritus Professor
RESEARCH INTERESTS
Communication Engineering
Scopus Publications
Scopus Publications
Ahmed A. Naser, Khalil H. Sayidmarie, and Jabir S. Aziz
Springer International Publishing
Abdullah A. Marzah and Jabir S. Aziz
IEEE
This work introduces the design, simulation, and implementation of a high-performance bandpass filter (BPF) for wireless applications. Size reduction becomes an important condition in filter design with minimum reflection coefficient, low insertion loss, out of band rejection, linear phase and flat group delay. Also, these filters needed to be easily integrated with transceivers and should be manufactured at a low cost. In this design, the microstrip structure was used with electrically coupled open loop resonators BPF based on Moore fractal geometry technique. FR-4 substrate with dielectric constant 4.3, and thickness 1.6 mm has been used. The proposed filter that centered at the 5.8 GHz frequency is simulated and evaluated using CST microwave studio package. The proposed filter structure is then fabricated to experimentally validate the simulated parameters, insertion loss and return loss in the desired bands of interest and out of band rejection level. Results of simulation and implementation show that the proposed filter possesses high performances and minimum size (with dimensions of 8.83 mm × 6 mm) enabling their use in a variety of wireless communication applications.
Mohammed Z. Hadi and Jabir S. Aziz
IEEE
In the current era, the rapid growth of wireless communications is leading to mass spectrum, which made the need to the monitoring systems that need unique antennas with ultra-wide bandwidth and reduced size in order to monitor and control the spectrum. Planar monopole antenna PMA is the preferred solution to design a reduced size and ultra-wide bandwidth antenna. This paper presents the design and implementation of new printed elliptical monopole antenna PEMA operating in the frequency range 1–18 GHz with very low input reflection coefficient (−15 dB on average) for EM radiation monitoring applications. The antenna bandwidth was further increased with a modified elliptical ground. Design and parameters optimization of the modified elliptical ground fulfill the bandwidth and input reflection coefficient requirements. Simulation results are introduced and validated with the measured ones. The antenna was printed on an FR4 substrate of 1.6 mm thickness and the resultant size of the proposed antenna is 75 mm × 65 mm.
Abdullah A. Marzah and Jabir S. Aziz
ACM Press
RF/Microwave filters represent an important component in most modern wireless communication systems since they reject unwanted signals (noise) and pass the required frequencies. Emerging new generations and development of communication systems need for good performance and miniaturized Band Pass Filters (BPFs). Minkowski fractals used as a miniaturization technique has been applied to slotted hexagonal loop resonator for designing BPF operate at a 3.5GHz resonance frequency which is suitable for WiMAX applications. The proposed filter has been designed using FR-4 substrate with dielectric constant 4.3 and thickness 1.6mm. More than one structure has been simulated. The overall dimensions of the second iteration Minkowski fractal proposed BPF are 7.07mm x 9.88mm which is demonstrates 80.46% reduction in size as compared with conventional closed hexagonal loop resonator BPF. CST microwave studio suite software package has been used in the simulation.
Abdullah A. Marzah and Jabir S. Aziz
IEEE
The band pass filter (BPF) is an important component that used in transmitter and receiver of a microwave communication system. The aim of this study is to design miniaturized BPF by fractal geometry techniques using microstrip structure. Meander line technique compound with Minkowski fractals was used for extra size reduction. The proposed BPF designed at center frequency 2.4 GHz which is used in industrial scientific medical (ISM) band applications with bandwidth 429 MHz (FBW=17.6%). The proposed filtering structure was designed using FR-4 substrate with 4.3 dielectric constant and 1.6mm thickness. The proposed filter demonstrates 1.6 dB insertion loss, 17 dB return loss, and size reduction about 74.5% as compared with conventional design. The overall dimensions of designed filter (14.18mm x 13.01mm) which equal to (0.2λgx0.18λg). CST microwave studio tools used in the design and simulation of the proposed BPFs.
Ahmad S. Abdulrasool, Jabir S. Aziz, and Sadiq J. Abou-Loukh
IEEE
The design and optimization of cellular communication networks in mountainous and hilly areas requires extra caution. The main problems are the shadowing resulted from obstruction and overshooting resulted from excessive elevation of base station or mobile. The empirical propagation models are used for the design and optimization of cellular networks, but such models do not consider the effect of shadowing or elevation fluctuation as they do not consider the terrain details strictly. The site-specific models are accurate, but the high complexity and time requirement limit their use for such purposes. This paper proposes a simplified propagation model with good accuracy that can be used for coverage prediction in mountainous nature areas. Also, the proposed model uses layering mechanism similar to Geographic Information System (GIS) in topographic layers to reduce the computation overhead and time by processing each layer alone. The validation of the proposed model will be done by comparing the results with field measurements. A coverage optimization case study using the proposed model will be done as well.
Ahmad S. Abdulrasool, Jabir S. Aziz, and Sadiq J. Abou-Loukh
IEEE
The accuracy of the propagation model is very crucial factor for successful wireless network design and optimization. The current existing models’ accuracy depends on the environment on which the network is being operated, thus the accuracy of the model deviate from one environment to another. The amount of deviation depends on the similarity between the environments at which the model was developed and the environments at which the model is being applied. This paper introduces a simple hybrid coverage prediction model for rural areas using hybrid of two models. The proposed model is based on layering mechanism similar to GIS topographic layers to reduce the computation overhead and time by processing each layer alone. The proposed model will be validated by comparing the results with field measurements. Also, a case study for coverage optimization using the proposed model will be done.
Ahmed A. Naser, Khalil H. Sayidmarie, and Jabir S. Aziz
IEEE
The favorable features of the Long-Term Evolution (LTE) standard has attracted much interest. At the lower bands of the LTE systems, designers of mobile handsets antennas face challenges of the conflicting requirements of limited space and long wavelengths. A multi-band PIFA antenna that is printed directly on the substrate is proposed for mobile handset applications. A parametric study using the CST Microwave Suite is presented to show the influences of various design parameters. The antenna design was optimized to attain a bandwidth of (0.67 GHz) centered at (2 GHz). The antenna has a compact size of 60×30×1.6mm3, and can be used to serve many LTE bands in the range of (1.7 GHz) to (2.37 GHz). A prototype antenna was fabricated for experimental evaluation where good agreement between simulated and measured results was obtained.
Ahmad S. Abdulrasool, Jabir S. Aziz, and Sadiq J. Abou-Loukh
Hindawi Limited
Applying propagation models with good accuracy is an essential issue for increasing the capacity and improving the coverage of cellular communication systems. This work presents an algorithm to calculate total diffraction losses for multiple obstacles objects using Epstein–Peterson approach. The proposed algorithmic procedure to model the diffracting can be integrated with other propagation mechanisms in ray-tracing for the prediction of received signal level in non-line-of-sight environments. This algorithm can be interpreted into software application to scan large areas with a reasonable simulation time.
Ahmed A. Naser, Khalil Hassan Sayidmarie, and Jabir S. Aziz
The Electromagnetics Academy
MIMO systems have become an essential part in many communications networks and Long Term Evolution (4G) mobile communication systems. Mobile handsets using lower band of LTE (LTE- 700 band) require antennas of reduced size that can be adapted to the limited space in the handset. This paper presents the design, optimization and implementation of two meandered-line PIFA antennas working as an MIMO system with high isolation for LTE-700 band mobile applications. To solve the problem of mutual coupling, a combination of decoupling arrangements was used to improve the isolation between the two antennas. The influences of various design parameters are investigated using the CST Microwave Studio Suite. A prototype of the proposed Meandered-line PIFA Antenna was fabricated and tested using vector network analyzer. Good agreement was found between the simulated and measured results. The fabricated MIMO antenna shows an isolation better than 12 dB and a �6 dB bandwidth of (75 MHz) in the frequency range from (720 MHz) to (795 MHz). The antenna has 1.94 dB gain, total efficiency of 85%, and volume of 110 × 65 × 1. 6m m 3 ,t hat is (0.275 × 0.1625 × 0.004) in wavelengths.
Ahmed A. Naser, Khalil H. Sayidmarie, and Jabir S. Aziz
IEEE
The long-term evolution (LTE) standard has attracted much interest due to its many advantages. Antenna design for the lower band of the LTE systems for mobile handsets faces challenges of the limited space and long wavelengths. An LTE smart mobile antenna is presented, and influences of various design parameters are investigated using the CST Microwave Suite. The antenna shape was then modified to obtain a bandwidth of (50) MHz centered at (767) MHz, and VSWR of 1.163. The antenna has compact size of 60×15×0.8mm3 (0.154×0.038×0.002 wavelengths at center frequency).
Ahmed A. Naser, Khalil H. Sayidmarie, and Jabir S. Aziz
IEEE
The long-term evolution (LTE) standard has attracted much interest because it offers many advantages. Antenna designers for the lower band of the LTE700 band for mobile handsets have to compromise between the limited space in the handset and long wavelengths implied by frequency of operation. An antenna with meandered line-PIFA combination is proposed as a solution for the above challenge. The influences of various design parameters are investigated using the CST Microwave Studio Suite. The antenna shape was then optimized to obtain a -6dB bandwidth of (58) MHz centered at (765) MHz. The antenna offers a second band at 2.16GHz for other applications. The antenna has compact size of 65×110×1.6mm3 (0.165×0.28×0.004 wavelengths at the center frequency of the lower band).
Dhrgham. K. Naji, Jaber. S. Aziz, and Raad S. Fyath
SAGE Publications
Different fractal antennas based on aperture coupled feeding technique are studied, analysed and compared for size reduction, low profile, and good omini-dirctional pattern suitable for RFID applications. The results are used as a guideline to propose modified fractal shapes patch antennas having lower size reduction parameters. All the designed antennas are based on zero - order square patch antenna where different fractal geometries are introduced to miniaturize the size of antenna for 5.8 GHz band. A maximum reduction in patch antenna size of 59.80 % is achieved when using modified Minkowski pre-fractal patch antenna.
Jabir Salman Aziz, Abbas Ahmed AL-Shalchi, Anwar Kasim Al-Kateeb, and F.N. Pavlidou
IEEE
The paper deals with the estimation of two main parameters of frequency-hopping spread spectrum (FH-SS) signals': hop rate and epoch time. Hop rate is the number of frequency changes per second and it is equivalent to the code clock rate. Epoch time is the timing offset between the first hop and the receiver's clock when the transmitter and the receiver are not synchronized. Multiple-hop autocorrelation (MHAC) processor is used for estimating the hop rate of FH signals in the presence of broadband thermal noise. During the hopping time, the single-hop autocorrelation (SHAC) processor can be also used to estimate the epoch time. Previous work on both estimators assumes precise knowledge of the signal power, which in practical applications is usually not available apriori. Therefore modified MHAC and SHAC estimators are proposed here, which do not require prior knowledge of signal power. However, the signal power is estimated first and then utilized in the hop rate or epoch time estimation .The performance of the proposed estimators has been tested using extensive computational experiments. The estimators of hop rate for known and unknown signal power approach the same value for signal-to-noise ratio (SNR) ges 0 dB and the error in the estimation < 10% and similar results were obtained for epoch time, while the error in the estimation of signal power < 5% for SNR ges 0 dB.