Khairul Najmy Abdul Rani
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Preferred name
Khairul Najmy Abdul Rani
Official Name
Abdul Rani, Khairul Najmy
Alternative Name
Rani, Khairul Najmy Abdul
Rani, Khairul Najmy Abd
Rani, K. N.A.
Abdul Rani, K. N.
Rani, Khairul N.Abdul
Abdul Rani, Khairul Najmy
Rani, K. N.Abdul
Main Affiliation
Scopus Author ID
57210770305
Researcher ID
GBP-6810-2022

Research Output

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  • Publication
    Split Ring Resonator Array Metamaterial of Zero Index Unit Cell Configuration
    ( 2022-01-01)
    Mohd Aminudin Jamlos
    ;
    Othman N.A.
    ;
    Wan Azani Wan Mustafa
    ;
    Hasliza A Rahim @ Samsuddin
    ;
    Al-Kharasan I.H.
    ;
    Khairul Najmy Abdul Rani
    A split-ring resonator (SRR) array metamaterial of zero-index unit cell configuration has been proposed. The SRR is made up of four loops; r1, r2, r3, and r4, which are inductance related, and the gaps (slots) are introduced to the ring to create the capacitance effect. The split ring is designed and simulated using sophisticated simulation software to have accurate simulation results. The SRR is placed between two waveguide terminals on the z-axis, at the top and bottom of the z-axis, respectively. SRR unit cell is configured into two array structures with a size of 110 x 65 mm2 which are the 7 x 4-unit cell and the 10 x 5-unit cell. A parametric study has been carried out for the split ring resonator to find the optimized design to have zero index as well as positive permittivity and permeability at the desired frequency of 2.7 GHz. Both array configurations recorded zero index (phase) at the desired frequency of 2.70 GHz. The positive on the point of close to zero results of the real part of permittivity and permeability lies at frequency 2.70 GHz as well.
  • Publication
    Hybridization of strength pareto multiobjective optimization with modified Cuckoo search algorithm for rectangular array
    ( 2017-04-20)
    Khairul Najmy Abdul Rani
    ;
    Mohamedfareq Abdulmalek
    ;
    Hasliza A Rahim @ Samsuddin
    ;
    Neoh Siew Chin
    ;
    Alawiyah Abd Wahab
    This research proposes the various versions of modified cuckoo search (MCS) metaheuristic algorithm deploying the strength Pareto evolutionary algorithm (SPEA) multiobjective (MO) optimization technique in rectangular array geometry synthesis. Precisely, the MCS algorithm is proposed by incorporating the Roulette wheel selection operator to choose the initial host nests (individuals) that give better results, adaptive inertia weight to control the positions exploration of the potential best host nests (solutions), and dynamic discovery rate to manage the fraction probability of finding the best host nests in 3-dimensional search space. In addition, the MCS algorithm is hybridized with the particle swarm optimization (PSO) and hill climbing (HC) stochastic techniques along with the standard strength Pareto evolutionary algorithm (SPEA) forming the MCSPSOSPEA and MCSHCSPEA, respectively. All the proposed MCS-based algorithms are examined to perform MO optimization on Zitzler-Deb-Thiele's (ZDT's) test functions. Pareto optimum trade-offs are done to generate a set of three non-dominated solutions, which are locations, excitation amplitudes, and excitation phases of array elements, respectively. Overall, simulations demonstrates that the proposed MCSPSOSPEA outperforms other compatible competitors, in gaining a high antenna directivity, small half-power beamwidth (HPBW), low average side lobe level (SLL) suppression, and/or significant predefined nulls mitigation, simultaneously.
  • Publication
    5.8 GHz Circularly Polarized Rectangular Microstrip Antenna Arrays simulation for Point-to-Point Application
    ( 2022-11-01)
    Mohd Aminudin Jamlos
    ;
    Sabri N.H.M.
    ;
    Jamlos M.F.
    ;
    Wan Azani Wan Mustafa
    ;
    Syed Zulkarnain Syed Idrus
    ;
    Mohamad Nur Khairul Hafizi Rohani
    ;
    Khairul Najmy Abdul Rani
    ;
    Mohd Al-Hafiz Mohd Nawi
    In this paper, the design and simulation of rectangular microstrip antenna arrays for improving antenna gain is performed for point-to-point application. The circular polarization is proposed to restrict the limitation of linear polarization which is less reliable in base station antenna. The circular polarization antenna is made to allow the receiver constantly to receive the power at any wave angle and make the transmission between two antennas are more constant. The proposed design is composed of four elements microstrip antenna with an array configuration operating at 5.8 GHz. Each element is constructed from four truncated arrays radiating elements and an inclined slot on each patch which capable to achieve circular polarized capability. The design of the 2x1 and 2x2 of rectangular microstrip array antenna was implemented from the design of single rectangular patch antenna as the basic building element. The designed 2x1 and 2x2 array were fed by microstrip transmission line which applied a technique of quarter wave impedance matching. The antenna design was etched on Rogers RT 5880 substrate with 2.1 and 1.53 mm of dielectric constant and thickness respectively. All the designed structure were simulated in CST software. The main results of the designed antennas were compared in terms of gain, axial ratio and return loss. Based on the return loss simulation results, the designed antennas resonated exactly at the desired resonant frequency of 5.8 GHz which indicates good antenna designs. Compared to the single patch antenna having an antenna gain of 8.26 dB, the 2x1 and 2x2 arrays achieved a gain of 10.24 dB and 13.29 dB respectively. The results show that the designed rectangular microstrip antenna arrays have an improved gain performance over the single patch antenna.
  • Publication
    Perpendicular High Isolation MIMO Antenna
    ( 2022-01-01)
    Mohd Aminudin Jamlos
    ;
    Sabri N.H.M.
    ;
    Wan Azani Wan Mustafa
    ;
    Khairul Najmy Abdul Rani
    ;
    Syed Zulkarnain Syed Idrus
    ;
    Husna H.
    This research presented a perpendicular high isolation MIMO antenna for LTE advance application. A high gain perpendicular MIMO antenna is concentrated on designing used in LTE advance application. The issues of low isolation of conventional antenna can be solved by structuring a MIMO antenna in order to increase the isolation in LTE advance application. Generally, the array antenna design causes a bigger antenna size and has a mutual coupling which lead to spectral efficiency damage and reduce the MIMO antenna framework performance. The substrate material like FR-4 is choosing as a dielectric substrate due to its good performances for many applications beside it has a low cost and more usable. The advantage of copper such as has a great relative material, cheaper and easy to construct is choose in this project as a conductive material. ADS software has been utilized for the structure stage to design the antenna. Then, the results are evaluated in terms of return loss (S11 and S22), mutual coupling (S12 and S21), match impedance, directivity, radiation pattern, gain and radiated power. Vector Network Analyzer (VNA) is used to measure the fabricated antenna. The factor of cable loses and the soldering technique will make the measurement result was slightly change from the simulating result. However, the antenna design satisfied the proficiency necessity of the antenna which the frequency is drop at 2.5 GHz with the return loss is below than −10 dB.
  • Publication
    Linear antenna array synthesis using the enhanced and hybrid cuckoo search metaheuristic algorithms
    ( 2014)
    Khairul Najmy Abdul Rani
    The antenna geometry synthesis plays an important role to determine the physical layout of the antenna array, which produces the radiation pattern closest to the actual desired pattern. The synthesis can be realized by defining the location of antenna array elements, and by choosing suitable excitation of amplitude, and excitation phase applied on the antenna array elements. Many synthesis techniques are done through suppressing the side lobe level (SLL) and/or mitigating prescribed nulls while simultaneously maintaining or improving the major lobe radiation intensity. Studies show that some conventional analytical, numerical, and modern evolutionary algorithm (EA) or evolutionary computation (EC) techniques have certain limitations in antenna array geometry synthesis. This includes beamwidth expanding and directivity saturation in amplitude tapering, exhaustive checking impairment in analytical method, disparity predicament between local and global search accelerators in particle swarm optimization (PSO), and drawbacks of crossover and mutation operators in genetic algorithm (GA). This thesis presents the sequential development of enhanced and hybrid versions of cuckoo search (CS) metaheuristic algorithm as an alternative of EA/EC technique for symmetric linear antenna array synthesis. Firstly, the proposal of the modified CS (MCS) algorithm through the integration with the Roulette wheel selection operator, dynamic inertia weight, and dynamic discovery rate controlling the best solutions exploration for a single objective (SO) optimization. Secondly, there is the hybridization of MCS with PSO (MCSPSO), and MCS with GA (MCSGA) in both SO and weighted−sum multiobjective (MO) approaches. Thirdly, the proposed amalgamation of MCS with strength Pareto evolutionary algorithm (MCSSPEA), hill climbing (HC) stochastic method within MCSSPEA algorithm (MCSHCSPEA), and PSO within MCSSPEA algorithm (MCSPSOSPEA) equipped with distance expansion formulae to reduce local trap problem. These newly techniques are specifically for Pareto MO optimization to find non−dominated solutions including element location, excitation amplitude, and excitation phase. All the tested algorithms development, source code writing, and results execution are performed using MATLAB scientific software. The optimal solutions are then compared against corresponding counterparts. Based on simulation results, the proposed MCSPSO outperforms other SO and weighted−sum MO algorithms whereas the proposed MCSPSOSPEA algorithm surpasses other tested Pareto MO algorithms in SLL suppression and/or nulls mitigation whilst achieving a high linear antenna directivity, and small half−power beamwidth (HPBW), respectively.
  • Publication
    Bending Assessment of Dual-band Split Ring-shaped and Bar Slotted All-Textile Antenna for Off-body WBAN/WLAN and 5G Applications
    ( 2020-09-28)
    Mashaghba H.A.
    ;
    Hasliza A Rahim @ Samsuddin
    ;
    Soh Ping Jack
    ;
    Abdulmalek M.
    ;
    Ismahayati Adam
    ;
    Muzammil Jusoh
    ;
    Thennarasan Sabapathy
    ;
    Mohd Najib Mohd Yasin
    ;
    Khairul Najmy Abdul Rani
    This paper presents a dual-band split ring-shaped and bar slotted textile antenna for potential WBAN/WLAN and 5G applications. The antenna is made using textiles and features a full ground plane to possibly alleviate coupling to the human body. The overall size of the antenna is 70 x 70 mm2, with a patch sized at 47.2 x 31 mm2 0.472 \lambda \times 0.031 \lambda. The antenna is made using ShieldIt Super as its conductive textile and felt as its substrate. To enable its dual-band resonance at 2.45 and 3.5 GHz a split ring-shaped and bar slots are integrated onto the patch. The proposed antenna is evaluated when bent under different radii and at different axes to estimate its performance in terms of reflection coefficient, bandwidth, efficiency and gain. A 10-dB impedance bandwidth of 57 % or 135 MHz (from 2.39 to 2.52 GHz) and 70 % or 240 MHz (from 3.45 to 3.56 GHz) are obtained when evaluated in the planar /bent configuration. The maximum realized gain is 6 dBi for at 3.5 GHz. These performances indicate that the antenna proposed in this work can be potentially improved for applications in WBAN/WLAN and 5G bands.
  • Publication
    The effects of metallic loop-like accessory worn on the human body on SAR at 2.45 GHz
    ( 2017-12-11)
    Zainal H.H.
    ;
    Hasliza A Rahim @ Samsuddin
    ;
    Soh Ping Jack
    ;
    Khairul Najmy Abdul Rani
    ;
    Herwansyah Lago
    ;
    Muhammad Solihin Zulkefli
    ;
    Yah N.F.N.
    This paper presents the Specific Absorption Rates (SAR) in the human body with a monopole antenna. The distance between the antenna and the body were varied at different distances. The parameters (ϵr, σ) used in the human body set according to the standard tissue equivalent liquids recommended by the IEEE and FCC. The simulations were made by means of CST Microwave Studio software at frequencies of 2.45GHz.The effect of the body on the SAR calculation in the body were measured. The SAR values were recorded in term of SAR for 10g of tissue. The TM is positioned against the metallic loop-like accessory, place on the left wrist of the generic arm at a varied distance from the cylindrical phantom. Numerical analysis conducted using a broadband textile monopole antenna (TM) with variations of orientation and distance showed that SAR values increased when the TM is horizontally polarized.
  • Publication
    Hybridization of strength pareto multiobjective optimization with modified cuckoo search algorithm for rectangular array
    ( 2017)
    Khairul Najmy Abdul Rani
    ;
    Mohamedfareq Abdulmalek
    ;
    Hasliza A Rahim @ Samsuddin
    ;
    Neoh Siew Chin
    ;
    Alawiyah Abd Wahab
    This research proposes the various versions of modified cuckoo search (MCS) metaheuristic algorithm deploying the strength Pareto evolutionary algorithm (SPEA) multiobjective (MO) optimization technique in rectangular array geometry synthesis. Precisely, the MCS algorithm is proposed by incorporating the Roulette wheel selection operator to choose the initial host nests (individuals) that give better results, adaptive inertia weight to control the positions exploration of the potential best host nests (solutions), and dynamic discovery rate to manage the fraction probability of finding the best host nests in 3-dimensional search space. In addition, the MCS algorithm is hybridized with the particle swarm optimization (PSO) and hill climbing (HC) stochastic techniques along with the standard strength Pareto evolutionary algorithm (SPEA) forming the MCSPSOSPEA and MCSHCSPEA, respectively. All the proposed MCS-based algorithms are examined to perform MO optimization on Zitzler–Deb–Thiele’s (ZDT’s) test functions. Pareto optimum trade-offs are done to generate a set of three non-dominated solutions, which are locations, excitation amplitudes, and excitation phases of array elements, respectively. Overall, simulations demonstrates that the proposed MCSPSOSPEA outperforms other compatible competitors, in gaining a high antenna directivity, small half-power beamwidth (HPBW), low average side lobe level (SLL) suppression, and/or significant predefined nulls mitigation, simultaneously.
  • Publication
    Compact Parallel Coupled Line Microstrip BPF Design for 5G Applications
    ( 2023-01-01)
    Anak Temuli H.U.
    ;
    Khairul Najmy Abdul Rani
    ;
    Fairul Afzal Ahmad Fuad
    ;
    Khairil Syahmi Musa
    ;
    Norfatihah Bahari
    ;
    Faizah Abu Bakar
    ;
    Mohd Aminudin Jamlos
    ;
    Rahayu Y.
    A compact parallel coupled line microstrip bandpass filter (BPF) for sub-6 GHz fifth generation (5G) applications is designed operating between edge frequencies of 3.40 and 3.80 GHz. The design is designed and simulated by means of the Advanced Design System (ADS) software using the flame retardant-4 (FR-4) board as the substrate. The BPF design applies the insertion loss method (ILM) to generate a parallel coupled line filter structure that performs passband permission and unwanted noise attenuation below 3.40 GHz and above 3.80 GHz, respectively. Consistent and relevant performances in terms of matching impedance, return loss (S11), insertion loss (S21), voltage standing wave ratio (VSWR), far field radiation pattern, gain, directivity, and radiated efficiency promise the microstrip BPF design has a potential for sub-6 GHz 5G applications.
  • Publication
    Flexible UWB Compact Circular Split-Ring Slotted Wearable Textile Antenna for Off-Body Millimetre-Wave 5G Mobile Communication
    ( 2020-01-01)
    Lee H.W.
    ;
    Hasliza A Rahim @ Samsuddin
    ;
    Abdulmalek M.
    ;
    R Badlishah Ahmad
    ;
    Jamaluddin M.H.
    ;
    Muzammil Jusoh
    ;
    Mohsin D.A.
    ;
    Wee Fwen Hoon
    ;
    Ismahayati Adam
    ;
    Yahya N.Z.
    ;
    Khairul Najmy Abdul Rani
    A flexible ultra-wideband (UWB) compact circular split-ring slotted wearable textile antenna for off-body 28 GHz fifth-generation (5G) mobile communication is proposed. The proposed antenna is implemented using low-cost felt textile substrates and copper. The proposed 5G wearable antenna of compact circular split-ring slotted with enhanced bandwidth of 0.5% with the resonance frequency of 28 GHz is presented. The S11 for patch antenna with slot exhibited 43.4% more than the patch antenna without slot. The results also exhibited that the bending angle of 10° and 20° perform better return loss than in flat condition, up to 14% for patch antenna with slot against without the slot.