A bandwidth-enhanced dual-polarized antenna is proposed for 2/3/4/5G applications,which is composed of distributed parasitic elements(DPEs),a main radiator,two improved broadband integrated baluns and a reflector.Firs...A bandwidth-enhanced dual-polarized antenna is proposed for 2/3/4/5G applications,which is composed of distributed parasitic elements(DPEs),a main radiator,two improved broadband integrated baluns and a reflector.First,a novel tooth-shape shorted slot line in the improved broadband integrated balun is analyzed to adjust the input impedance of the antenna.Then,DPEs with 2×2 circular plates loading over the main radiator are proposed to improve broadband impedance matching and radiation pattern.By utilizing impedance compensation of the tooth-shaped shorted slot line and the electromagnetic induction of the DPEs,the antenna achieves an enhanced impedance bandwidth and a stable radiation pattern.To verify these ideas,the bandwidth-enhanced dual-polarized antenna was fabricated and measured.The experimental results indicate that the proposed antenna achieves an operating bandwidth of 72.2%(1.69 to 3.60 GHz)with a return loss(RL)less than-15 dB and a port-to-port isolation(ISO)larger than 30 dB.The antenna obtains a half-power beamwidth(HPBW)within(66±5)°and a gain within(9.0±0.6)dBi in the 2/3/4G bands,and an HPBW within(61.5±2.5)°and a gain within(9.8±0.3)dBi in the 5G band.Across the whole band,the cross-polarization discrimination(XPD)and the front-to-back ratio are both larger than 20 dB.展开更多
The fifth-generation(5G)wireless technology is the most recent standardization in communication services of interest across the globe.The concept of Multiple-Input-Multiple-Output antenna(MIMO)systems has recently bee...The fifth-generation(5G)wireless technology is the most recent standardization in communication services of interest across the globe.The concept of Multiple-Input-Multiple-Output antenna(MIMO)systems has recently been incorporated to operate at higher frequencies without limitations.This paper addresses,design of a high-gain MIMO antenna that offers a bandwidth of 400 MHz and 2.58 GHz by resonating at 28 and 38 GHz,respectively for 5G millimeter(mm)-wave applications.The proposed design is developed on a RT Duroid 5880 substrate with a single elemental dimension of 9.53×7.85×0.8 mm^(3).The patch antenna is fully grounded and is fed with a 50-ohm stepped impedance microstrip line.It also has an I-shaped slot and two electromagnetically coupled parasitic slotted components.This design is initially constructed as a single-element structure and proceeded to a six-element MIMO antenna configuration with overall dimensions of 50×35×0.8 mm^(3).The simulated prototype is fabricated and measured for analyzing its performance characteristics,along with MIMO antenna diversity performance factors making the proposed antenna suitable for 5G mm-wave and 5G-operated handheld devices.展开更多
This paper proposes a new dielectric resonator antenna(DRA)design that can generate circularly polarized(CP)triple-band signals.Atripleband CP DRA antenna fed by a probe feed system is achieved with metal strips struc...This paper proposes a new dielectric resonator antenna(DRA)design that can generate circularly polarized(CP)triple-band signals.Atripleband CP DRA antenna fed by a probe feed system is achieved with metal strips structure on side of DRA structure.The design start with conventional rectangular DRA with F shaped metal strips on DRA structure alongside the feed.Then,the F metal strip is enhanced by extending the length of the metal strip to obtain wider impedance bandwidth.Further improvement on the antenna performance is observed by improvised the conventional DRA structure.The method of removing part of DRA bottom resulted to higher antenna gain with triple band CP.The primary features of the proposed DRA include wide impedance matching bandwidth(BW)and broadband circular polarization(CP).The primary features of the proposedDRAinclude wide impedance matching bandwidth(BW)and broadband circular polarization(CP).The CP BW values recorded by the proposed antenna were∼11.27%(3.3–3.65 GHz),12.18%(4.17–4.69 GHz),and 1.74%(6.44–6.55 GHz)for impedance-matching BW values of 35.4%(3.3–4.69 GHz),1.74%(5.36–5.44 GHz),and 1.85%(6.41–6.55 GHz)with peak gains of 6.8 dBic,7.6 dBic,and 8.5 dBic,respectively,in the lower,central,and upper bands.The prototype of the proposed antenna geometry was fabricated and measured.A good agreement was noted between the simulated and the measured results.展开更多
In this paper,single-phase homogeneous nanofluid model is proposed to investigate the natural convection of magneto-hydrodynamic(MIID)flow of Newtonian Cu—H20 nanoliquid in a baffled U-shaped enclosure.The Brin...In this paper,single-phase homogeneous nanofluid model is proposed to investigate the natural convection of magneto-hydrodynamic(MIID)flow of Newtonian Cu—H20 nanoliquid in a baffled U-shaped enclosure.The Brinkman model and Wasp model are considered to measure the effective dynamic viscosity and effective thermal conductivity of the nanoliquid coreespondingly.Nanoliquid's effective properties such as specific heat,density and thermal expansion coefficient are modeled using mixture theory.The complicated PDS(partial differential system)is treated for numeric solutions via the Galerkin finite element method.The pertinent parameters Hartmann number(1≤Ha≤60),Rayleigh number(10^(3)≤Ra≤10^(6))and nanoparticles volume fraction (0% ≤Ф≤4%) are taken for the parametric analysis, and it is conducted via streamlines and isotherms. Excellent agreement between numerical results and open literature. It is ascertained that heat transfer rate enhances with Rayleigh number Ra and volume fraction 0, however it is diminished for laiger Hartmann number Ha.展开更多
It is critical to build a wide-band circuit model to conduct research on the characteristics of the electromagnetic disturbance source during the localization of high voltage direct current(HVDC)technology.Parasitic c...It is critical to build a wide-band circuit model to conduct research on the characteristics of the electromagnetic disturbance source during the localization of high voltage direct current(HVDC)technology.Parasitic capacitance is most essential for modeling the equivalent circuit,so a fast and accurate computation of capacitance parameters plays a vital role.Because of the large size and complex structure of the converter equipment,it is impossible to obtain capacitance parameters by means of measurement or simulating calculation with finite element software.In this paper,a simplified method of capacitance extraction based on boundary element method is proposed,which can provide an efficient means of establishing simulation models.In the method presented,simulation model of the shield may not be chamfered.Consequently,the edge and corner of the shield do not need to be handled with a sphere,cylinder and other curved surface model.The availability of this method is demonstrated by comparing the capacitance parameters of chamfered shield with that of non-chamfered shield.展开更多
基金The National Natural Science Foundation of China(No.61471117).
文摘A bandwidth-enhanced dual-polarized antenna is proposed for 2/3/4/5G applications,which is composed of distributed parasitic elements(DPEs),a main radiator,two improved broadband integrated baluns and a reflector.First,a novel tooth-shape shorted slot line in the improved broadband integrated balun is analyzed to adjust the input impedance of the antenna.Then,DPEs with 2×2 circular plates loading over the main radiator are proposed to improve broadband impedance matching and radiation pattern.By utilizing impedance compensation of the tooth-shaped shorted slot line and the electromagnetic induction of the DPEs,the antenna achieves an enhanced impedance bandwidth and a stable radiation pattern.To verify these ideas,the bandwidth-enhanced dual-polarized antenna was fabricated and measured.The experimental results indicate that the proposed antenna achieves an operating bandwidth of 72.2%(1.69 to 3.60 GHz)with a return loss(RL)less than-15 dB and a port-to-port isolation(ISO)larger than 30 dB.The antenna obtains a half-power beamwidth(HPBW)within(66±5)°and a gain within(9.0±0.6)dBi in the 2/3/4G bands,and an HPBW within(61.5±2.5)°and a gain within(9.8±0.3)dBi in the 5G band.Across the whole band,the cross-polarization discrimination(XPD)and the front-to-back ratio are both larger than 20 dB.
文摘The fifth-generation(5G)wireless technology is the most recent standardization in communication services of interest across the globe.The concept of Multiple-Input-Multiple-Output antenna(MIMO)systems has recently been incorporated to operate at higher frequencies without limitations.This paper addresses,design of a high-gain MIMO antenna that offers a bandwidth of 400 MHz and 2.58 GHz by resonating at 28 and 38 GHz,respectively for 5G millimeter(mm)-wave applications.The proposed design is developed on a RT Duroid 5880 substrate with a single elemental dimension of 9.53×7.85×0.8 mm^(3).The patch antenna is fully grounded and is fed with a 50-ohm stepped impedance microstrip line.It also has an I-shaped slot and two electromagnetically coupled parasitic slotted components.This design is initially constructed as a single-element structure and proceeded to a six-element MIMO antenna configuration with overall dimensions of 50×35×0.8 mm^(3).The simulated prototype is fabricated and measured for analyzing its performance characteristics,along with MIMO antenna diversity performance factors making the proposed antenna suitable for 5G mm-wave and 5G-operated handheld devices.
文摘This paper proposes a new dielectric resonator antenna(DRA)design that can generate circularly polarized(CP)triple-band signals.Atripleband CP DRA antenna fed by a probe feed system is achieved with metal strips structure on side of DRA structure.The design start with conventional rectangular DRA with F shaped metal strips on DRA structure alongside the feed.Then,the F metal strip is enhanced by extending the length of the metal strip to obtain wider impedance bandwidth.Further improvement on the antenna performance is observed by improvised the conventional DRA structure.The method of removing part of DRA bottom resulted to higher antenna gain with triple band CP.The primary features of the proposed DRA include wide impedance matching bandwidth(BW)and broadband circular polarization(CP).The primary features of the proposedDRAinclude wide impedance matching bandwidth(BW)and broadband circular polarization(CP).The CP BW values recorded by the proposed antenna were∼11.27%(3.3–3.65 GHz),12.18%(4.17–4.69 GHz),and 1.74%(6.44–6.55 GHz)for impedance-matching BW values of 35.4%(3.3–4.69 GHz),1.74%(5.36–5.44 GHz),and 1.85%(6.41–6.55 GHz)with peak gains of 6.8 dBic,7.6 dBic,and 8.5 dBic,respectively,in the lower,central,and upper bands.The prototype of the proposed antenna geometry was fabricated and measured.A good agreement was noted between the simulated and the measured results.
基金the Algerian Ministry of Higher Education and Scientific Research through PRFU project no B00L02UN210120180002the General Directorate of Scientific Research and Technological Development(DGRSDT),Algeria.
文摘In this paper,single-phase homogeneous nanofluid model is proposed to investigate the natural convection of magneto-hydrodynamic(MIID)flow of Newtonian Cu—H20 nanoliquid in a baffled U-shaped enclosure.The Brinkman model and Wasp model are considered to measure the effective dynamic viscosity and effective thermal conductivity of the nanoliquid coreespondingly.Nanoliquid's effective properties such as specific heat,density and thermal expansion coefficient are modeled using mixture theory.The complicated PDS(partial differential system)is treated for numeric solutions via the Galerkin finite element method.The pertinent parameters Hartmann number(1≤Ha≤60),Rayleigh number(10^(3)≤Ra≤10^(6))and nanoparticles volume fraction (0% ≤Ф≤4%) are taken for the parametric analysis, and it is conducted via streamlines and isotherms. Excellent agreement between numerical results and open literature. It is ascertained that heat transfer rate enhances with Rayleigh number Ra and volume fraction 0, however it is diminished for laiger Hartmann number Ha.
文摘It is critical to build a wide-band circuit model to conduct research on the characteristics of the electromagnetic disturbance source during the localization of high voltage direct current(HVDC)technology.Parasitic capacitance is most essential for modeling the equivalent circuit,so a fast and accurate computation of capacitance parameters plays a vital role.Because of the large size and complex structure of the converter equipment,it is impossible to obtain capacitance parameters by means of measurement or simulating calculation with finite element software.In this paper,a simplified method of capacitance extraction based on boundary element method is proposed,which can provide an efficient means of establishing simulation models.In the method presented,simulation model of the shield may not be chamfered.Consequently,the edge and corner of the shield do not need to be handled with a sphere,cylinder and other curved surface model.The availability of this method is demonstrated by comparing the capacitance parameters of chamfered shield with that of non-chamfered shield.
