In this paper, Finite Difference Time Domain (FDTD) is utilized to simulate metamaterials of Double Negative (DNG) origin that refers to those materials having simultaneous negative permittivity and permeability. The ...In this paper, Finite Difference Time Domain (FDTD) is utilized to simulate metamaterials of Double Negative (DNG) origin that refers to those materials having simultaneous negative permittivity and permeability. The problem regarding space formulation is achieved by means of auxiliary differential equation method (ADE), which is easy, reliable and also causal process in nature thus making it proficient. It uses fair approximations to explicate the model. Mur’s boundary condition is used for 1-D problem space and convolution perfectly matched layer boundary is implemented for 2-D problem space. The properties of metamaterial conform their speculations of energy absorption, enhancement and backward propagation property with the aid of graphs engineered by Matlab simulation both in 1-D and 2-D. Also, the interaction of fields on DNG and Double Positive (DPS) layers is contrasted. The results achieved elucidate the validity and effectiveness of the ADE method and the Convolution Perfectly Match Layer (CPML) in designing DNG metamaterials.展开更多
This study proposed a new royal crown-shaped polarisation insensitive double negative triple band microwave range electromagnetic metamaterial absorber(MA).The primary purpose of this study is to utilise the exotic ch...This study proposed a new royal crown-shaped polarisation insensitive double negative triple band microwave range electromagnetic metamaterial absorber(MA).The primary purpose of this study is to utilise the exotic characteristics of this perfect metamaterial absorber(PMA)for microwave wireless communications.The fundamental unit cell of the proposed MA consists of two pentagonal-shaped resonators and two inverse C-shaped metallic components surrounded by a split ring resonator(SRR).The bottom thin copper deposit and upper metallic resonator surface are disjoined by an FR-4 dielectric substrate with 1.6 mm thickness.The CST MW studio,a high-frequency electromagnetic simulator has been deployed for numerical simula-tion of the unit cell in the frequency range of 4 to 14 GHz.In the TE mode,the offered MA structure demonstrated three different absorption peaks at 6.85 GHz(C-band),8.87 GHz(X-band),and 12.03 GHz(Ku-band),with 96.82%,99.24%,and 99.43%absorptivity,respectively.The electric field,magnetic field,and surface current distribution were analysed using Maxwell’s-Curl equations,whereas the angle sensitivity was investigated to comprehend the absorption mechanism of the proposed absorber.The numerical results were verified using the Ansys HFSS(high-frequency structure simulator)and ADS(advanced design system)for equivalent circuit models.Moreover,the proposed MA is polarisation and incident angle independent.Hence,the application of this MA can be extended to a great extent,including airborne radar applications,defence,and stealth-coating technology.展开更多
This paper presents a textile-based C-shaped split-ring resonators(SRR)metamaterial(MTM)unit cells with an electrical tunability function.The proposed MTM was composed of two symmetrical C-shaped SRR combined with a c...This paper presents a textile-based C-shaped split-ring resonators(SRR)metamaterial(MTM)unit cells with an electrical tunability function.The proposed MTM was composed of two symmetrical C-shaped SRR combined with a central diagonal metal bar,whereas the RF varactor diode is placed on the backside of the splitted ground plane.Stopband behavior of single and array MTM unit cells were analyzed while the achieved negative index physical characteristics were widely studies.Though four different MTM arrays(i.e.,1×1,1×2,2×1,and 2×2)were analyzed in simulation,a 2×2-unit cell array was chosen to fabricate,and it was further undergone experimental validation.This proposed tunable MTM exhibits double negative(DNG)/left-handed properties with an average bandwidth of more than 2.8 GHz.Furthermore,attainable negative permittivity and negative permeability are within 2.66 to 9.59 GHz and within 2.77 to 15 GHz,respectively,at the frequency of interest(between 1 and 15 GHz).Moreover,the proposed tunable MTM also showed tunable transmission coefficient characteristics.The proposed electrically tunable textile MTM might function in a dynamic mode,making it suitable for a variety of microwave-wearable applications.A satisfactory agreement between simulations and experiments were achieved,demonstrating that the proposed MTM can operate over a wide bandwidth.展开更多
A novel metamaterial structure has been proposed for Electromagnetic Compatibility (EMC) applications. A patch antenna with dimension of 18 mm × 13.9 mm and resonating at 5 GHz has been designed and the effect of...A novel metamaterial structure has been proposed for Electromagnetic Compatibility (EMC) applications. A patch antenna with dimension of 18 mm × 13.9 mm and resonating at 5 GHz has been designed and the effect of Double Negative (DNG) metamaterial loading for the patch size reduction as well as a lowering in resonance frequency for the fixed size patch antenna has been proposed. A size reduction of 72.5% in the patch antenna has been obtained with the loading of this metamaterial structure and the effect of loading the metamaterial shows that without reducing the size, the patch antenna can work at 3.7 GHz resonance, providing a lowering in resonance frequency by 26%. The metamaterial structure consists of two concentric loops with an outer radius of 3.1 mm. The width of the ring is 1.0 mm and the split is 0.5 mm and has been designed over a 1.57 mm thick Fr4 substrate. The bending effect of the patch antenna with and without metamaterial loading and its comparison with the planar patch antenna has been also shown here. The metamaterial structure has shown its resonance at 5 GHz and its permittivity and permeability behavior over the desired frequency range has been plotted. The simulation of traditional patch antenna and patch antenna over metamaterial has been compared for its return loss, VSWR, gain and efficiency. Finally, a spice circuit for the S parameter of the metamaterial, patch antenna and patch antenna loaded with metamaterial has been obtained using Matlab and ADS for its equivalence to 3D field solver and its comparison has been plotted for its verification.展开更多
文摘In this paper, Finite Difference Time Domain (FDTD) is utilized to simulate metamaterials of Double Negative (DNG) origin that refers to those materials having simultaneous negative permittivity and permeability. The problem regarding space formulation is achieved by means of auxiliary differential equation method (ADE), which is easy, reliable and also causal process in nature thus making it proficient. It uses fair approximations to explicate the model. Mur’s boundary condition is used for 1-D problem space and convolution perfectly matched layer boundary is implemented for 2-D problem space. The properties of metamaterial conform their speculations of energy absorption, enhancement and backward propagation property with the aid of graphs engineered by Matlab simulation both in 1-D and 2-D. Also, the interaction of fields on DNG and Double Positive (DPS) layers is contrasted. The results achieved elucidate the validity and effectiveness of the ADE method and the Convolution Perfectly Match Layer (CPML) in designing DNG metamaterials.
基金supported by Fundamental Research Grant Scheme(FRGS),MOE,Malaysia,Code:FRGS/1/2022/TK07/UKM/02/22.
文摘This study proposed a new royal crown-shaped polarisation insensitive double negative triple band microwave range electromagnetic metamaterial absorber(MA).The primary purpose of this study is to utilise the exotic characteristics of this perfect metamaterial absorber(PMA)for microwave wireless communications.The fundamental unit cell of the proposed MA consists of two pentagonal-shaped resonators and two inverse C-shaped metallic components surrounded by a split ring resonator(SRR).The bottom thin copper deposit and upper metallic resonator surface are disjoined by an FR-4 dielectric substrate with 1.6 mm thickness.The CST MW studio,a high-frequency electromagnetic simulator has been deployed for numerical simula-tion of the unit cell in the frequency range of 4 to 14 GHz.In the TE mode,the offered MA structure demonstrated three different absorption peaks at 6.85 GHz(C-band),8.87 GHz(X-band),and 12.03 GHz(Ku-band),with 96.82%,99.24%,and 99.43%absorptivity,respectively.The electric field,magnetic field,and surface current distribution were analysed using Maxwell’s-Curl equations,whereas the angle sensitivity was investigated to comprehend the absorption mechanism of the proposed absorber.The numerical results were verified using the Ansys HFSS(high-frequency structure simulator)and ADS(advanced design system)for equivalent circuit models.Moreover,the proposed MA is polarisation and incident angle independent.Hence,the application of this MA can be extended to a great extent,including airborne radar applications,defence,and stealth-coating technology.
基金This work is supported by the Universiti Kebangsaan Malaysia Research Grant under Grant Number.GUP-2020-017.
文摘This paper presents a textile-based C-shaped split-ring resonators(SRR)metamaterial(MTM)unit cells with an electrical tunability function.The proposed MTM was composed of two symmetrical C-shaped SRR combined with a central diagonal metal bar,whereas the RF varactor diode is placed on the backside of the splitted ground plane.Stopband behavior of single and array MTM unit cells were analyzed while the achieved negative index physical characteristics were widely studies.Though four different MTM arrays(i.e.,1×1,1×2,2×1,and 2×2)were analyzed in simulation,a 2×2-unit cell array was chosen to fabricate,and it was further undergone experimental validation.This proposed tunable MTM exhibits double negative(DNG)/left-handed properties with an average bandwidth of more than 2.8 GHz.Furthermore,attainable negative permittivity and negative permeability are within 2.66 to 9.59 GHz and within 2.77 to 15 GHz,respectively,at the frequency of interest(between 1 and 15 GHz).Moreover,the proposed tunable MTM also showed tunable transmission coefficient characteristics.The proposed electrically tunable textile MTM might function in a dynamic mode,making it suitable for a variety of microwave-wearable applications.A satisfactory agreement between simulations and experiments were achieved,demonstrating that the proposed MTM can operate over a wide bandwidth.
文摘A novel metamaterial structure has been proposed for Electromagnetic Compatibility (EMC) applications. A patch antenna with dimension of 18 mm × 13.9 mm and resonating at 5 GHz has been designed and the effect of Double Negative (DNG) metamaterial loading for the patch size reduction as well as a lowering in resonance frequency for the fixed size patch antenna has been proposed. A size reduction of 72.5% in the patch antenna has been obtained with the loading of this metamaterial structure and the effect of loading the metamaterial shows that without reducing the size, the patch antenna can work at 3.7 GHz resonance, providing a lowering in resonance frequency by 26%. The metamaterial structure consists of two concentric loops with an outer radius of 3.1 mm. The width of the ring is 1.0 mm and the split is 0.5 mm and has been designed over a 1.57 mm thick Fr4 substrate. The bending effect of the patch antenna with and without metamaterial loading and its comparison with the planar patch antenna has been also shown here. The metamaterial structure has shown its resonance at 5 GHz and its permittivity and permeability behavior over the desired frequency range has been plotted. The simulation of traditional patch antenna and patch antenna over metamaterial has been compared for its return loss, VSWR, gain and efficiency. Finally, a spice circuit for the S parameter of the metamaterial, patch antenna and patch antenna loaded with metamaterial has been obtained using Matlab and ADS for its equivalence to 3D field solver and its comparison has been plotted for its verification.
