Z. Zakaria
Universiti Teknikal Malaysia Melaka (UTeM)

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Radiation pattern control of microstrip antenna in elevation and azimuth planes using EBG and pin diode. M. K Abdulhameed; M. S. Mohamad Isa; Z. Zakaria; I.M. Ibrahim; Mowafak K. Mohsen
International Journal of Electrical and Computer Engineering (IJECE) Vol 9, No 1: February 2019
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2030.269 KB) | DOI: 10.11591/ijece.v9i1.pp332-340

Abstract

An important issue in wireless communication systems, which is related to the antenna gain degradation in case of changing the main direction of the antenna radiation pattern, this variation is not approval in many communications systems. In order to improve antenna radiation performances, Electromagnetic band gap (EBG) - antenna with radiation pattern control capability is presented. Mushroom-like EBG structure for suppressing surface waves has been combined, with the switching diode to produce the radiation pattern control with improving antenna characteristics of gain, directivity and efficiency. EBG of several cells are surrounded the patch antenna and placed symmetrically for the two opposite sides, generating different radiation patterns control ability in both the elevation (E) (-20° < φ < 20°) and azimuth (Z) planes (−18° < θ < 18°). At the ground plane of antenna the diodes have been switched ON and OFF states, the EBG sector properties in stop band (connecting vias) and pass band (disconnecting vias) are altered. Using CST Microwave Studio (CST MWS) the results show the flexibility in radiation pattern control for the Z and E planes using only four diodes. Antenna directivity of 10 dBi, gain 9.86 dB and efficiency 96.5% at the operating frequency of 6 GHz, more results for all direction has been stated in Table1. Significantly, unlike a conventional beam steering, this method does not suffering from gain degradation and the main lobe gain is approximately constant for all steerig angles.
Hybrid Microstrip Diplexer Design for Multi-band WiMAX Application in 2.3 and 3.5 GHz Bands M. A. Sazali; N. A. Shairi; Z. Zakaria
International Journal of Electrical and Computer Engineering (IJECE) Vol 8, No 1: February 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1018.574 KB) | DOI: 10.11591/ijece.v8i1.pp576-584

Abstract

In this paper, a design of hybrid microstrip diplexer is proposed for multi-band Worldwide Interoperability for Microwave Access (WiMAX) application in 2.3 and 3.5 GHz bands. The diplexer consists of a combination of two different filter designs. These filters were designed based on microstripline coupling techniques in order to obtain minimum insertion losses and achieve the desired frequency bandwidth. Therefore, a coupled open loop ring resonator was chosen for the filter design in 2.3 GHz band and a folded coupled line resonator was chosen for the filter design in 3.5 GHz band. Then, these filters were combined with a ring manifold matching network to be a hybrid microstrip diplexer. Based on the results, good agreements were achieved between the simulation and measurement results in terms of insertion loss, return loss and bandwidth in the 2.3 and 3.5 GHz bands.
Mushroom-Like EBG to Improve Patch Antenna Performance For C-Band Satellite Application M. K. Abdulhameed; M. S. Mohamad Isa; Z. Zakaria; Mowafak K. Mohsin; Mothana L. Attiah
International Journal of Electrical and Computer Engineering (IJECE) Vol 8, No 5: October 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (787.276 KB) | DOI: 10.11591/ijece.v8i5.pp3875-3881

Abstract

In order to suppress the surface waves excitation that are caused by thick substrate in a patch antenna, a mushroom-like EBG (Electromagnetic Band Gap) structure is used. Such structures enhance its characteristics of gain, directivity, bandwidth and efficiency. Firstly, we determined frequency band gap characteristics of mushroom like EBG unit cell value by using CST software with 3mm (0.06λo) for covering 6 GHz. The periodic arrangement of such mushroom-like EBG structures was not limited by any interconnecting microstrip lines. Four columns of EBGs shifted inwards to antenna edges by 0.3mm (0.06λo) or a gap of its design around the patch from the left and right sides. Different configurations were also examined in order to get the better improvement in antenna performance. The final design of this mushroom-like shifted periodic structure shows an effective increase in the directivity by 77%, gain by 108%, bandwidth by 29% and the efficiency by 20% for the antenna. This structure has diversified application possibility for wireless and satellite communications.
Side lobe reduction in array antenna by using novel design of EBG Muhannad Kaml Abdulhameed; M. S. Mohamad Isa; I. M. Ibrahim; Z. Zakaria; Mowafak K. Mohsen; Mothana L. Attiah; Ahmed M. Dinar
International Journal of Electrical and Computer Engineering (IJECE) Vol 10, No 1: February 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (824.228 KB) | DOI: 10.11591/ijece.v10i1.pp308-315

Abstract

A novel design of EBG is used to replace the mushroom like EBG for surrounding the array patch antenna. In order to improve its radiation performances, Electromagnetic band stop for reducing the surface waves effects is presented. The novel design of Triple Side Slotted EBG (TSSEBG) showed an improvement in the antenna efficiency, directivity and gain as compared to the reference antenna without using EBG, due to reduce the surface waves effects which leads to decrease the side lobes. TSSEBG has been introduced by some modifications in conventional mushroom-like EBG structure. Reducing the complexity was achieved by reducing the number of unit cells and vias, in case of used TSSEBG instead of mushroom like EBG. Additionally, the TSSEBG provided triple band gap compared with mushroom like EBG structure which had only one band gap frequency at 6 GHz. The placement of TSSEBG is a flexible structure which provides a good choice in the antenna applications. The simulation results of array patch antenna with and without mushroom like EBG and TSSEBG are arranged in Table 1. This structure has vast applications in satellite communications.
Accurate characterizations of material using microwave T-resonator for solid sensing applications Rammah A. Alahnomi; Z. Zakaria; Zulkalnain Mohd Yussof; Tole Sutikno; H. Sariera; Amyrul Azuan Mohd Bahar
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 18, No 1: February 2020
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v18i1.14880

Abstract

The topic of microwave sensors in enclosures is one of the most active areas in material characterization research today due to its wide applications in various industries. Surprisingly, a microwave sensor technology has been comprehensively investigated and there is an industry demand for an accurate instrument of material characterization such as food industry, quality control, chemical composition analysis and bio-sensing. These accurate instruments have the ability to understand the properties of materials composition based on chemical, physical, magnetic, and electric characteristics. Therefore, a design of the T-resonator has been introduced and investigated for an accurate measurement of material properties characterizations. This sensor is designed and fabricated on a 0.787 mm-thickness Roger 5880 substrate for the first resonant frequency to resonate at 2.4 GHz under unloaded conditions. Various standard dielectric of the sample under test (SUT) are tested to validate the sensitivity which making it a promising low-cost, compact in size, ease of fabrication and small SUT preparation for applications requiring novel sensing techniques in quality and control industries.
Electronically controlled radiation pattern leaky wave antenna array for (C band) application Mowafak K. Mohsen; M. S. M. Isa; Z. Zakaria; A. A. M. Isa; M. K. Abdulhameed; Mothana L. Attiah; Ahmed M. Dinar
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 2: April 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i2.11126

Abstract

This paper provides an insight of a new, leaky-wave antenna (LWA) array. It holds the ability to digitally steer its beam at a fixed frequency by utilizing only two state of bias voltage. This is done with acceptable impedance matching while scanning and very little gain variation. Investigation is carried out on LWAs’ control radiation pattern in steps at a fixed frequency via PIN diodes switches. This study also presents a novel half-width microstrip LWA (HWMLWA) array. The antenna is made up of the following basic structures: two elements and reconfigurable control cell with each being comprised of two diodes and two triangle patches. A double gap capacitor in each unit cell is independently disconnected or connected via PIN diode switch to achieve fixed-frequency control radiation pattern. The reactance profile at the microstrip’s free edge and thus the main beam direction is changed once the control-cell states are changed. The main beam may be directed by the antenna between 61o and 19o at 4.2 GHz. C band achieved the measured peak gain of the antenna of 15 dBi at 4.2 GHz beam scanning range.
Enhanced symmetrical split ring resonator for metallic surface crack detection Rammah A. Alahnomi; Z. Zakaria; Zulkalnain Mohd Yussof; Tole Sutikno; Ammar Alhegazi; Ahmed Ismail Abu-Khadrah
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 4: August 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i4.12939

Abstract

An enhanced sensor based on symmetrical split ring resonator (SSRR) functioning at microwave frequencies has been proposed in order to detect and characterize the metal crack of the materials. This sensor is based on perturbation theory, in which the dielectric properties of the material affect the quality factor and resonance frequency of the microwave resonator. Conventionally, coaxial cavity, waveguide, dielectric resonator techniques have been used for characterizing materials. However, these techniques are often large, and expensive to build, which restricts their use in many important applications. Thus, the enhanced bio-sensing technique presents advantages such as high measurement sensitivity with the capability of suppressing undesired harmonic spurious and permits potentially metal crack material detection. Hence, using a High Frequency Structure Simulator (HFSS) software, the enhanced sensor is modeled and the reflection S11 is performed for testing the aluminum metal with crack and without crack at the frequency range of 100 MHz to 3GHz. Variation of crack width and depth has been investigated and the most obvious finding emerged from this study is that the ability of detecting a minimum of sub-millimeter crack width and depth which is a round 10 ????m width or depth where the minimum shift of reflected frequency is recorded at 6.2 MHz and 3 MHz for crack width and depth respectively. The enhanced SSRR provides high capability of detecting small crack defection by utilizing the interaction between coupled gap resonators and it is useful for various applications such as aircraft fuselages, nuclear power plant steam generator tubing, and steel bridges and for others that can be compromised by metal fatigue.
Design and development broadband monopole antenna for in-door application Ali Abdulateef Abdulbari; Z. Zakaria; Sharul Kamal Abdul Rahim; Yaqthan Mahmood Hussein; Mustafa Mohammed Jawad; Ayad Muslim Hamzah
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 18, No 1: February 2020
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v18i1.13171

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.
Analysis of switching and matching stubs in reconfigurable power divider with SPDT switch function N. Edward; N. A. Shairi; Z. Zakaria; I. D. Saiful Bahri
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 1: February 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i1.11714

Abstract

In this paper, performance analysis of switching and matching stubs was done to a reconfigurable power divider with Single Pole Double Throw (SPDT) switch function. Two designs (Design A and Design B) with different positions of switches and matching stubs were proposed. Rogers RO4350 (er=3.48, h=0.508 mm) was used in this analysis as a substrate material with copper thickness of 0.035 mm. The performance analysis was carried out based on insertion loss, return loss and isolation parameters. The simulated results showed that Design B had a better performance than Design A and was able to work as a reconfigurable power divider with SPDT switch function.
Novel design of triple-bands EBG M. K. Abdulhameed; M. S. Mohamad Isa; Z. Zakaria; I. M. Ibrahim; Mowafak K. Mohsen; Ahmed M. Dinar; Mothana L. Attiah
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 4: August 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i4.12616

Abstract

This paper presents a novel design for a triple band electromagnetic band gap (EBG) structures that provides three band gaps, with operating frequency of below 10 GHz, while the ordinary mushroom like EBG structure gives only one band gap. Complexity reduction (reduce the number of unit cells and Vias) was achieved by replacing each four cells of the Mushroom like EBG by the one of double slotted type EBG (DSTEBG) or triple side slotted EBG (TSSEBG). The Mushroom like EBG was further modified by increasing its size and inserting the slots to gain more capacitance and inductance which resulted into triple band stop.The new designs wer compared with bandwidths expressed by other EBGs and -20 dB cut-off frequencies. The size of EBG element and the gap between EBG elements, and slot width were investigated to analyse their effect on the transmission response. The structures were designed from 2.54 mm Rogers RT/Duroid 6010 substrate with relative permittivity of 10.2 and loss tangent of 0.0023. Among the investigated EBGs, the single band mushroom like EBG and the triple band of the TSSEBG demonstrated better bandwidth and lower resonance frequency performance, whereas the DSTEBG showed larger bandwidth for the first and third band. The proposed EBGs could be useful in the antenna design and other microwave circuits.