This work proposes a wideband and unidirectional antenna consisting of dual layer of coplanar waveguide based on the circular parasitic element technique.The design procedure is implemented in three stages:Design A,wh...This work proposes a wideband and unidirectional antenna consisting of dual layer of coplanar waveguide based on the circular parasitic element technique.The design procedure is implemented in three stages:Design A,which operates at 3.94 GHz with a bandwidth of 3.83 GHz and a fractional bandwidth(FBW)of 97.2%;Design B,which operates at 3.98 GHz with a bandwidth of 0.66 GHz(FBW of 56.53%);and Design C as the final antenna.The final Design C is designed to resonate at several frequencies between 2.89 and 7.0 GHz for microwave imaging applications with a bandwidth of 4.11 GHz(79.8%)centered at 5.15 GHz.This antenna is fabricated fully using two textile materials:felt as the substrate and ShieldIt as the conductor.It features a unidirectional radiation with a gain of 5.5 dBi,and reduced lowback radiation from 2.06 to−7.81 dB.The front-to-back ratio(FBR)for Design A,Design B and Design C are 4.82,2.94 and 11.36 dB,respectively.This antenna is wideband with unidirectional radiation,lightweight,and flexible.展开更多
This paper introduces a decagonal C-shaped complementary splitring resonator(CSRR)textile-based metamaterial(MTM).The overall size of the proposed sub-wavelength MTM unit cell is 0.28λ0×0.255λ0 at 3 GHz.Its sto...This paper introduces a decagonal C-shaped complementary splitring resonator(CSRR)textile-based metamaterial(MTM).The overall size of the proposed sub-wavelength MTM unit cell is 0.28λ0×0.255λ0 at 3 GHz.Its stopband behaviour was first studied prior analysing the negative index properties of the proposed MTM.It is worth noting that in this work a unique way the experiments were completed.For both simulations and measurements,the proposed MTM exhibited negative-permittivity and negative-refractive index characteristics with an average bandwidth of more than 3 GHz(considering 1.7 to 8.2 GHz as the measurements were carried out within this range).In simulations,the MTM exhibited negative-permittivity properties within the range of 1.7 to 7.52 GHz and 7.96 to 8.2 GHz;and negative-refractive index from 1.7 to 2.23 GHz and 2.33 to 5.09 GHz and 5.63 to 7.45 GHz.When measured from 1.7 to 8.2 GHz,negative-permittivity and negative-refractive index characteristics are exhibited throughout an average bandwidth of more than 3 GHz.Similarly,the transmission coefficient attained in simulations and measurements indicated about 3 GHz of bandwidth,from 1.7 to 3.88 GHz and from 6.68 to 7.4 GHz.The satisfactory agreement between simulations and experiments indicates the potential of the proposed MTM for microwave applications.展开更多
This paper presents a flexible and wearable textile array antenna designed to generate Orbital Angular Momentum(OAM)waves with Mode+2 at 3.5 GHz(3.4 to 3.6 GHz)of the sub-6 GHz fifth-generation(5G)New Radio(NR)band.Th...This paper presents a flexible and wearable textile array antenna designed to generate Orbital Angular Momentum(OAM)waves with Mode+2 at 3.5 GHz(3.4 to 3.6 GHz)of the sub-6 GHz fifth-generation(5G)New Radio(NR)band.The proposed antenna is based on a uniform circular array of eight microstrip patch antennas on a felt textile substrate.In contrast to previous works involving the use of rigid substrates to generate OAM waves,this work explored the use of flexible substrates to generate OAM waves for the first time.Other than that,the proposed antenna was simulated,analyzed,fabricated,and tested to confirm the generation of OAMMode+2.With the same design,OAM Mode−2 can be generated readily simply by mirror imaging the feed network.Note that the proposed antenna operated at the desired frequency of 3.5 GHz with an overall bandwidth of 400 MHz in free space.Moreover,mode purity analysis is carried out to verify the generation of OAM Mode+2,and the purity obtained was 41.78%at free space flat condition.Furthermore,the effect of antenna bending on the purity of the generated OAM mode is also investigated.Lastly,the influence of textile properties on OAM modes is examined to assist future researchers in choosing suitable fabrics to design flexible OAM-based antennas.After a comprehensive analysis considering different factors related to wearable applications,this paper demonstrates the feasibility of generating OAMwaves using textile antennas.Furthermore,as per the obtained Specific Absorption Rate(SAR),it is found that the proposed antenna is safe to be deployed.The findings of this work have a significant implication for body-centric communications.展开更多
基金This work was supported in part by the Malaysia Public Service Department(JPA)and Universiti Teknikal Malaysia Melaka(UTeM)under Jurnal/2020/FKEKK/Q00053P.J.Soh acknowledges the support from the Academy of Finland 6 Genesis Flagship(Grant No.318927).
文摘This work proposes a wideband and unidirectional antenna consisting of dual layer of coplanar waveguide based on the circular parasitic element technique.The design procedure is implemented in three stages:Design A,which operates at 3.94 GHz with a bandwidth of 3.83 GHz and a fractional bandwidth(FBW)of 97.2%;Design B,which operates at 3.98 GHz with a bandwidth of 0.66 GHz(FBW of 56.53%);and Design C as the final antenna.The final Design C is designed to resonate at several frequencies between 2.89 and 7.0 GHz for microwave imaging applications with a bandwidth of 4.11 GHz(79.8%)centered at 5.15 GHz.This antenna is fabricated fully using two textile materials:felt as the substrate and ShieldIt as the conductor.It features a unidirectional radiation with a gain of 5.5 dBi,and reduced lowback radiation from 2.06 to−7.81 dB.The front-to-back ratio(FBR)for Design A,Design B and Design C are 4.82,2.94 and 11.36 dB,respectively.This antenna is wideband with unidirectional radiation,lightweight,and flexible.
基金This work was supported in part by the King Mongkut’s University of Technology North Bangkok(Grant no:KMUTNB-64-KNOW-12)in part by the by the Academy of Finland 6Genesis Flagship(Grant no:318927).
文摘This paper introduces a decagonal C-shaped complementary splitring resonator(CSRR)textile-based metamaterial(MTM).The overall size of the proposed sub-wavelength MTM unit cell is 0.28λ0×0.255λ0 at 3 GHz.Its stopband behaviour was first studied prior analysing the negative index properties of the proposed MTM.It is worth noting that in this work a unique way the experiments were completed.For both simulations and measurements,the proposed MTM exhibited negative-permittivity and negative-refractive index characteristics with an average bandwidth of more than 3 GHz(considering 1.7 to 8.2 GHz as the measurements were carried out within this range).In simulations,the MTM exhibited negative-permittivity properties within the range of 1.7 to 7.52 GHz and 7.96 to 8.2 GHz;and negative-refractive index from 1.7 to 2.23 GHz and 2.33 to 5.09 GHz and 5.63 to 7.45 GHz.When measured from 1.7 to 8.2 GHz,negative-permittivity and negative-refractive index characteristics are exhibited throughout an average bandwidth of more than 3 GHz.Similarly,the transmission coefficient attained in simulations and measurements indicated about 3 GHz of bandwidth,from 1.7 to 3.88 GHz and from 6.68 to 7.4 GHz.The satisfactory agreement between simulations and experiments indicates the potential of the proposed MTM for microwave applications.
基金This work was supported by Ministry of Higher Education through the Fundamental Research Grant Scheme(FRGS)under a grant number of FRGS/1/2020/ICT09/UNIMAP/02/2.
文摘This paper presents a flexible and wearable textile array antenna designed to generate Orbital Angular Momentum(OAM)waves with Mode+2 at 3.5 GHz(3.4 to 3.6 GHz)of the sub-6 GHz fifth-generation(5G)New Radio(NR)band.The proposed antenna is based on a uniform circular array of eight microstrip patch antennas on a felt textile substrate.In contrast to previous works involving the use of rigid substrates to generate OAM waves,this work explored the use of flexible substrates to generate OAM waves for the first time.Other than that,the proposed antenna was simulated,analyzed,fabricated,and tested to confirm the generation of OAMMode+2.With the same design,OAM Mode−2 can be generated readily simply by mirror imaging the feed network.Note that the proposed antenna operated at the desired frequency of 3.5 GHz with an overall bandwidth of 400 MHz in free space.Moreover,mode purity analysis is carried out to verify the generation of OAM Mode+2,and the purity obtained was 41.78%at free space flat condition.Furthermore,the effect of antenna bending on the purity of the generated OAM mode is also investigated.Lastly,the influence of textile properties on OAM modes is examined to assist future researchers in choosing suitable fabrics to design flexible OAM-based antennas.After a comprehensive analysis considering different factors related to wearable applications,this paper demonstrates the feasibility of generating OAMwaves using textile antennas.Furthermore,as per the obtained Specific Absorption Rate(SAR),it is found that the proposed antenna is safe to be deployed.The findings of this work have a significant implication for body-centric communications.
