A third-order correction was recently suggested to improve the accuracy of the half-power bandwidth method in estimating the damping of single DOF systems.This paper analyzes the accuracy of the half-power bandwidth m...A third-order correction was recently suggested to improve the accuracy of the half-power bandwidth method in estimating the damping of single DOF systems.This paper analyzes the accuracy of the half-power bandwidth method with the third-order correction in damping estimation for multi-DOF linear systems.Damping ratios in a two-DOF linear system are estimated using its displacement and acceleration frequency response curves,respectively.A wide range of important parameters that characterize the shape of these response curves are taken into account.Results show that the third-order correction may greatly improve the accuracy of the half-power bandwidth method in estimating damping in a two-DOF system.In spite of this,the half-power bandwidth method may significantly overestimate the damping ratios of two-DOF systems in some cases.展开更多
A backside illuminated mesa-structure In Ga As/In P modified uni-traveling-carrier photodiode（MUTC-PD） with wide bandwidth and high saturation power is fabricated and investigated. The device structure is optimized ...A backside illuminated mesa-structure In Ga As/In P modified uni-traveling-carrier photodiode（MUTC-PD） with wide bandwidth and high saturation power is fabricated and investigated. The device structure is optimized to reduce the capacitance and resistance. For the 22-μm-diameter device, the maximum responsivity at 1.55 μm is 0.5 A/W, and the 3-d B cutoff frequency reaches up to 28 GHz. The output photocurrent at the 1-d B compression point is measured to be 54 m A at 25 GHz, with a corresponding output radio frequency（RF） power of up to 15.5 d Bm. The saturation characteristics of the MUTC-PD are also verified by the electric field simulation, and electric field collapse is found to be the cause of the saturation phenomenon.展开更多
Two methods for improving the equidriving power-frequency characteristics of broad-band high power klystrons are presented. One is that a comb-line bandpass filter with someattenuation properties is inserted between t...Two methods for improving the equidriving power-frequency characteristics of broad-band high power klystrons are presented. One is that a comb-line bandpass filter with someattenuation properties is inserted between the TWT driver and the klystron for compensatingthe gain-frequency characteristics of the klystron to get the required equidriving power-frequencycharacteristics. The other is that a reactive element is connected with the input cavity to changeits resonance frequencies f<sub>0</sub> and Q<sub>L</sub>, and thus to improve the power-frequency characteristics ofthe klystron.展开更多
Interconnect power and repeater area are important in the interconnect optimization of nanometer scale integrated circuits. Based on the RLC interconnect delay model, by wire sizing, wire spacing arid adopting low-swi...Interconnect power and repeater area are important in the interconnect optimization of nanometer scale integrated circuits. Based on the RLC interconnect delay model, by wire sizing, wire spacing arid adopting low-swing interconnect technology, this paper proposed a power-area optimization model considering delay and bandwidth constraints simultaneously. The optimized model is verified based on 65-am and 90-nm complementary metal-oxide semiconductor （CMOS） interconnect parameters. The verified results show that averages of 36% of interconnect power and 26% of repeater area can be saved under 65-nm CMOS process. The proposed model is especially suitable for the computer-aided design of nanometer scale systems-on-chip.展开更多
基金National Natural Science Foundation under Grant No. 51179093National Basic Research Program of China under Grant No. 2011CB013602Program for New Century Excellent Talents in University under Grant No.NCET-10-0531
文摘A third-order correction was recently suggested to improve the accuracy of the half-power bandwidth method in estimating the damping of single DOF systems.This paper analyzes the accuracy of the half-power bandwidth method with the third-order correction in damping estimation for multi-DOF linear systems.Damping ratios in a two-DOF linear system are estimated using its displacement and acceleration frequency response curves,respectively.A wide range of important parameters that characterize the shape of these response curves are taken into account.Results show that the third-order correction may greatly improve the accuracy of the half-power bandwidth method in estimating damping in a two-DOF system.In spite of this,the half-power bandwidth method may significantly overestimate the damping ratios of two-DOF systems in some cases.
基金Project supported by the National Basic Research Program of China(Grant Nos.2012CB315605 and 2014CB340002)the National Natural Science Foundation of China(Grant Nos.61176015,61176059,61210014,61321004,and 61307024)the Open Fund of State Key Laboratory on Integrated Optoelectronics,China(Grant Nos.IOSKL2012KF08 and IOSKL2014KF09)
文摘A backside illuminated mesa-structure In Ga As/In P modified uni-traveling-carrier photodiode（MUTC-PD） with wide bandwidth and high saturation power is fabricated and investigated. The device structure is optimized to reduce the capacitance and resistance. For the 22-μm-diameter device, the maximum responsivity at 1.55 μm is 0.5 A/W, and the 3-d B cutoff frequency reaches up to 28 GHz. The output photocurrent at the 1-d B compression point is measured to be 54 m A at 25 GHz, with a corresponding output radio frequency（RF） power of up to 15.5 d Bm. The saturation characteristics of the MUTC-PD are also verified by the electric field simulation, and electric field collapse is found to be the cause of the saturation phenomenon.
文摘Two methods for improving the equidriving power-frequency characteristics of broad-band high power klystrons are presented. One is that a comb-line bandpass filter with someattenuation properties is inserted between the TWT driver and the klystron for compensatingthe gain-frequency characteristics of the klystron to get the required equidriving power-frequencycharacteristics. The other is that a reactive element is connected with the input cavity to changeits resonance frequencies f<sub>0</sub> and Q<sub>L</sub>, and thus to improve the power-frequency characteristics ofthe klystron.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60725415 and 60971066)the National High-Tech Program of China (Grant Nos. 2009AA01Z258 and 2009AA01Z260)the National Science & Technology Important Project of China (Grant No. 2009ZX01034-002-001-005)
文摘Interconnect power and repeater area are important in the interconnect optimization of nanometer scale integrated circuits. Based on the RLC interconnect delay model, by wire sizing, wire spacing arid adopting low-swing interconnect technology, this paper proposed a power-area optimization model considering delay and bandwidth constraints simultaneously. The optimized model is verified based on 65-am and 90-nm complementary metal-oxide semiconductor （CMOS） interconnect parameters. The verified results show that averages of 36% of interconnect power and 26% of repeater area can be saved under 65-nm CMOS process. The proposed model is especially suitable for the computer-aided design of nanometer scale systems-on-chip.
