A new method,namely multiple point curvature compensation (MPCC),is proposed for the design of a bandgap reference,and its design principles, theoretical derivation, and one feasible circuitry implementation are pre...A new method,namely multiple point curvature compensation (MPCC),is proposed for the design of a bandgap reference,and its design principles, theoretical derivation, and one feasible circuitry implementation are presented. Being different from traditional techniques, this idea focuses on finding multiple temperatures in the whole range at which the first order derivatives of the output reference voltage equal zero. In this way, the curve of the output reference voltage is flattened and a better effect of curvature compensation is achieved. The circuitry is simulated in ST Microelectronics 0. 18μm CMOS technology, and the simulated result shows that the average temperature coefficient is only 1ppm/℃ in the range from - 40 to 125℃.展开更多
On the basis of mutual compensation of mobility and threshold voltage temperature effects, a stable CMOS band-gap voltage reference circuit was designed and fabricated in CSMC-HJ 0.6 μm CMOS technology. Operating fro...On the basis of mutual compensation of mobility and threshold voltage temperature effects, a stable CMOS band-gap voltage reference circuit was designed and fabricated in CSMC-HJ 0.6 μm CMOS technology. Operating from 0 to 85 ℃ under a supply voltage ranging from 4.5 to 5.5 V, the voltage reference circuit offers an output reference voltage ranging from 1.122 to 1.176 V and a voltage variation less than ±3.70%. The chip size including bonding pads is only 0.4 mm×0.4 mm and the power dissipation falls inside the scope of 28.3 to 48.8 mW operating at a supply voltage of 4.5 to 5.5 V.展开更多
In this paper, numerical modelling of left-handed materials (LHMs) is presented using in-house and commercial software packages. Approaches used include the finite-difference time-domain (FDTD) method, finite elem...In this paper, numerical modelling of left-handed materials (LHMs) is presented using in-house and commercial software packages. Approaches used include the finite-difference time-domain (FDTD) method, finite element method (FEM) and method of moments (MoMs). Numerical simulation includes verification of negative refraction and "perfect lenses" construction, investigation of evanescent wave behaviour in layered LHMs, reversed Shell's Law in electromagnetic band gap (EBG)-like structures and construction of LHMs using modified split ring resonators (SRRs). Numerical results were verified to be in good agreement with theory, At the end of this paper, potential applications of LHMs in microwave engineering are discussed.展开更多
Air-core photonic bandgap fiber(PBF)is the perfect choice of the next-generation fiber optical gyroscope(FOG),with excellent temperature,electromagnetism and radiation adaptability.Numerical aperture is an important o...Air-core photonic bandgap fiber(PBF)is the perfect choice of the next-generation fiber optical gyroscope(FOG),with excellent temperature,electromagnetism and radiation adaptability.Numerical aperture is an important optical parameter of PBF for application in FOG.The PBF’s maximum theoretical numerical aperture(NAmax)is calculated and compared with the far-field numerical aperture(NAeff)through experiments.The result indicates that the relationship between NAmax and NAeff has much stronger dependence on wavelength than that of the conventional fiber,and they get close at wavelengths near the middle of the photonic bandgap with the error less than 5%.Furthermore,photonic bandgap fiber optical gyroscope(PBFOG)with no fusion splicing points is proposed,and the optimization method and results of the PBF’s structure parameters for application in PBFOG are given from the aspect of numerical aperture.展开更多
文摘A new method,namely multiple point curvature compensation (MPCC),is proposed for the design of a bandgap reference,and its design principles, theoretical derivation, and one feasible circuitry implementation are presented. Being different from traditional techniques, this idea focuses on finding multiple temperatures in the whole range at which the first order derivatives of the output reference voltage equal zero. In this way, the curve of the output reference voltage is flattened and a better effect of curvature compensation is achieved. The circuitry is simulated in ST Microelectronics 0. 18μm CMOS technology, and the simulated result shows that the average temperature coefficient is only 1ppm/℃ in the range from - 40 to 125℃.
文摘On the basis of mutual compensation of mobility and threshold voltage temperature effects, a stable CMOS band-gap voltage reference circuit was designed and fabricated in CSMC-HJ 0.6 μm CMOS technology. Operating from 0 to 85 ℃ under a supply voltage ranging from 4.5 to 5.5 V, the voltage reference circuit offers an output reference voltage ranging from 1.122 to 1.176 V and a voltage variation less than ±3.70%. The chip size including bonding pads is only 0.4 mm×0.4 mm and the power dissipation falls inside the scope of 28.3 to 48.8 mW operating at a supply voltage of 4.5 to 5.5 V.
基金Project supported by the Royal Society, the Engineering and PhysicsScience Research Council (EPSRC) and the Leverhulme Trust, UK
文摘In this paper, numerical modelling of left-handed materials (LHMs) is presented using in-house and commercial software packages. Approaches used include the finite-difference time-domain (FDTD) method, finite element method (FEM) and method of moments (MoMs). Numerical simulation includes verification of negative refraction and "perfect lenses" construction, investigation of evanescent wave behaviour in layered LHMs, reversed Shell's Law in electromagnetic band gap (EBG)-like structures and construction of LHMs using modified split ring resonators (SRRs). Numerical results were verified to be in good agreement with theory, At the end of this paper, potential applications of LHMs in microwave engineering are discussed.
基金supported by the National Natural Science Foundation of China(Grant No.61205077)
文摘Air-core photonic bandgap fiber(PBF)is the perfect choice of the next-generation fiber optical gyroscope(FOG),with excellent temperature,electromagnetism and radiation adaptability.Numerical aperture is an important optical parameter of PBF for application in FOG.The PBF’s maximum theoretical numerical aperture(NAmax)is calculated and compared with the far-field numerical aperture(NAeff)through experiments.The result indicates that the relationship between NAmax and NAeff has much stronger dependence on wavelength than that of the conventional fiber,and they get close at wavelengths near the middle of the photonic bandgap with the error less than 5%.Furthermore,photonic bandgap fiber optical gyroscope(PBFOG)with no fusion splicing points is proposed,and the optimization method and results of the PBF’s structure parameters for application in PBFOG are given from the aspect of numerical aperture.