Ali Abdulateef Abdulbari

Bio: Ali Abdulateef Abdulbari is an academic researcher from Universiti Teknologi Malaysia. The author has contributed to research in topics: Return loss & Wideband. The author has an hindex of 2, co-authored 3 publications receiving 5 citations.

New design of wideband microstrip branch line coupler using T-shape and open stub for 5G application

Abstract: A new design of wideband branch-line coupler (BLC) using T-shape with open stub microstrip line is proposed. The branch line coupler is integrated with low and high impedance λ/4 transmission lines to achieve the comparatively compact size of (27.2 mm × 16.5 mm). operating the bandwidth in simulated of BLC from 2.9 to 4 GHz is obtained 30.22% with a frequency center of 3.5 GHz. Meanwhile, the measured bandwidth of the BLC is cover from 2.8 GHz to 4.22 GHz is equal 33.40% at the center frequency 3.55 GHz respectively. The BLC simulated has low isolation and high return loss of -29.28 dB and -30.69 dB at the center frequency 3.5 GHz.Whereas, the measured result has a simple difference in the return loss and isolation are -27.43dB and -24.46 dB at the frequency 3.55GHz respectively. This BLC design has a good coupling factor of -2.97 and insertion loss of -3.65 dB. Furthermore, it obtains an excellent amplitude and phases different between two output of ±0.1 and 93.6°±3.4° with high performance. There is a good agreement between the simulated result and the measured result. This branch line coupler design used for 5G applications for future wireless communication systems.

Design and development broadband monopole antenna for in-door application

Abstract: This paper describes the broadband monopole antenna refers to a signal wideband of the frequencies, which can be divided the signal into channels of the frequency bins. Aim this paper to design and development broadband monopole antenna. The monopole antenna was designed by adding slot to the radiated patch antenna with a single feed line, which reduced the size and the design complexity. A rectangular patch antenna was presented using feed line to decrease the ground plane with a suitable gap distance. The broadband monopole antenna was designed with a frequency range of 800 MHz–3 GHz, with Bandwidth 0.66(dB), reflection coefficients and return loss. The frequency-dependent characteristic impedance was included. It can be used in various broadband applications in used commercially for various communication systems such as 4G (LTE), WiMAX and WLAN (LTE), remote sensing, biomedical, and mobile wireless. Apart from that, this technology is environment-friendly; an antenna which consists of reception and transmission. The antenna is simulated by using computer simulation (CST) software; a low cost of 4.4 permittivity FR-4 substrate is used. The measurement result is accepted with simulation result, proving the acceptable broadband operation for this proposed structure.

Single-Layer Planar Monopole Antenna-Based Artificial Magnetic Conductor (AMC)

Abstract: In this paper, a coplanar waveguide (CPW)-fed patch antenna is fabricated on a layer of metasurface to increase gain. The antenna is fabrication on Roger substrate with a thickness of 0.25 mm, with the overall dimension of the proposed design being 45 × 30 × 0.25 mm3. The size of the patch antenna is 24 × 14 × 0.25 mm3, and the AMC unit cell is 22 × 22 × 0.25 mm3. This metasurface is designed based on the split-ring resonator unit cells forming an array of the artificial magnetic conductor (AMC). Meanwhile, the antenna operation on 3.5 GHz is enabled by etching a split-ring resonator slot on the ground plane with a small gap to enhance antenna gain and improve impedance bandwidth when integrated with a metasurface. This simulation planer monopole antenna is applied for 5G application. The experimenter test is applied for the antenna performance in terms of return loss, gain, and radiation patterns. The operating frequency range with and without MTM is from 3.41 to 3.68 GHz (270 MHz) and 3.37 to 3.55 GHz (180 MHz), respectively, with gain improvements of about 2.7 dB (without MTM) to 6.0 dB (with MTM) at 3.5 GHz. The maximum improvement of the gain is about 42% when integrated with the AMC. The AMC has solved several issues to overcome the typical limitation in conventional antenna design. A circuit model is also proposed to simplify the estimation of the performance of this antenna at the desired frequency band. The proposed design is simulated by CST microwave studio. Finally, the antenna is fabricated and measured. Result comparison between simulations and measurements indicates a good agreement between them.

Single-Layer PlanarMonopole Antenna-Based ArtificialMagnetic Conductor (AMC)

Abstract: Wireless Communication Centre (WCC), School of Electrical Engineering, Universiti Teknologi Malaysia (UTM), Skudai 81310, Malaysia Department of Computer Techniques Engineering, Imam Al-Kadhum College (IKC), „i-Qar, Baghdad, Iraq Department of Mathematics, College of Education, Al-Zahraa University for Women Karbala, Karbala, Iraq Centre for Wireless Communications (CWC), University of Oulu, P. O Box 4500, 90014 Oulu, Finland Department of Computer Technical Engineering, College of Information Technology, Imam Ja’afar Al-Sadiq University, 66002 Al-Muthanna, Iraq Department of Medical Instrumentation Techniques Engineering, Al-Mustaqbal University College, Hillah 51001, Iraq Department of Signal „eory and Communications, Universidad Carlos III de Madrid, Leganes 28911, Madrid, Spain Centre for Telecommunication Research and Innovation (CeTRI), Faculty of Electronics and Computer Engineering, Universiti Teknikal Malaysia Melaka (UTeM), Melaka, Malaysia

Microwave Differential Circuit Design Using Mixed Mode S Parameters

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Miniaturized fractal rat-race, branch-line, and coupled-line hybrids

Abstract: In this paper, space-filling curves have been used to realize a family of miniaturized hybrids. The large surface area occupied by a conventional structure has been significantly reduced through the use of space-filling curves having the same electrical characteristics. Several space-filling curves have been studied and implemented in different designs. The second-iteration Moore rat-race coupler occupies only 12.6% of the conventional coupler's area, while the area of the second-iteration Sierpinski branch-line coupler is 24.7% of the conventional case. On the other hand, a nine-section Minkowski coupled-line balun is confined in 60% of the conventional balun's area. However, the effective size reduction depends on the used space-filling curve, compression ratio, and associated coupling between segments. The performance of the proposed space-filling hybrids is as good as that of the corresponding conventional structures, and even better in some cases. The design and simulation of the proposed space-filling hybrids have been performed using a moment-method-based full-wave electromagnetic simulator. Measurements of one fabricated coupler prototype are in good agreement with simulation results.

Design and Implementation of a beam steering antenna array using butler matrix feed network for X band applications

Abstract: This article proposes the design, simulation, fabrication and testing of a beam steerable antenna array using a 4 × 4 Butler Matrix feed network technique. The proposed antenna is developed to operate at the X band frequency range. The integrated antenna array and the Butler Matrix feed network operating at 10 GHz has a bandwidth of approximately 2 GHz with an achieved gain of 12 dBi. The main beam pattern of the antenna array is switched between four directions (+10°, −38°, +38°, −10°) providing an effective coverage of over 100°. The proposed antenna has the advantages of low cost, easy fabrication, and simplicity.

Single-Layer Planar Monopole Antenna-Based Artificial Magnetic Conductor (AMC)

Abstract: In this paper, a coplanar waveguide (CPW)-fed patch antenna is fabricated on a layer of metasurface to increase gain. The antenna is fabrication on Roger substrate with a thickness of 0.25 mm, with the overall dimension of the proposed design being 45 × 30 × 0.25 mm3. The size of the patch antenna is 24 × 14 × 0.25 mm3, and the AMC unit cell is 22 × 22 × 0.25 mm3. This metasurface is designed based on the split-ring resonator unit cells forming an array of the artificial magnetic conductor (AMC). Meanwhile, the antenna operation on 3.5 GHz is enabled by etching a split-ring resonator slot on the ground plane with a small gap to enhance antenna gain and improve impedance bandwidth when integrated with a metasurface. This simulation planer monopole antenna is applied for 5G application. The experimenter test is applied for the antenna performance in terms of return loss, gain, and radiation patterns. The operating frequency range with and without MTM is from 3.41 to 3.68 GHz (270 MHz) and 3.37 to 3.55 GHz (180 MHz), respectively, with gain improvements of about 2.7 dB (without MTM) to 6.0 dB (with MTM) at 3.5 GHz. The maximum improvement of the gain is about 42% when integrated with the AMC. The AMC has solved several issues to overcome the typical limitation in conventional antenna design. A circuit model is also proposed to simplify the estimation of the performance of this antenna at the desired frequency band. The proposed design is simulated by CST microwave studio. Finally, the antenna is fabricated and measured. Result comparison between simulations and measurements indicates a good agreement between them.

A 4 × 4 Millimeterwave-Frequency Butler Matrix in Grounded Co-Planar Waveguide Technology for Compact Integration With 5G Antenna Arrays

Abstract: This article presents a novel $4\times 4$ Butler matrix implemented in the grounded co-planar waveguide (GCPW) technology, compactly integrated with a highly efficient and broadband $1\times 4$ air-filled substrate integrated waveguide (AFSIW) cavity-backed patch antenna array (AA), giving rise to a broad operational frequency range [23.75, 31 GHz] (26.5%) covering the n257, n258, and n261 fifth-generation (5G) bands. Three novel quadrature hybrid couplers and two crossovers are designed and compared to obtain the optimal building blocks for the Butler matrix. Within each of the supported 5G bands, the measured excess insertion loss of the optimized Butler matrix remains smaller than 3.5dB with a maximal amplitude imbalance of ±0.9dB. Isolation between input ports is higher than 16.4dB. A maximal measured realized gain of 12.3dBi is obtained for the Butler matrix with integrated $1\times 4$ AA while ensuring a −3-dB beamwidth coverage of 110°. The main beamsteering directions of [−40°, −14°, 14°, 40°] exhibit measured deviations that stay within ±3°. The fabricated Butler matrix with AA features a very compact footprint of 21.4 mm $\times$ 46.0 mm $\times $ 2 mm [ $2\lambda _{0} \times 4.3\lambda _{0} \times 0.2\lambda _{0}$ ].