The characteristic impedances of L-type and T-type networks are first investigated for a distributed amplifier design.The analysis shows that the L-type network has better frequency characteristics than the T-type one...The characteristic impedances of L-type and T-type networks are first investigated for a distributed amplifier design.The analysis shows that the L-type network has better frequency characteristics than the T-type one.A distribution amplifier based on the L-type network is implemented with the 2-μm GaAs HBT（heterojunction-bipolar transistor） process of WIN semiconductors.The measurement result presents excellent bandwidth performance and gives a gain of 5.5 dB with a gain flatness of ±1dB over a frequency range from 3 to 18 GHz.The return losses S11 and S22 are below-10dB in the designed frequency range.The output 1-dB compression point at 5 GHz is 13.3 dBm.The chip area is 0.95 mm2 and the power dissipation is 95 mW under a 3.5 V supply.展开更多
An improved single-π equivalent circuit model for on-chip inductors in the GaAs process is presented in this paper. Considering high order parasites, the model is established by comprising an improved skin effect bra...An improved single-π equivalent circuit model for on-chip inductors in the GaAs process is presented in this paper. Considering high order parasites, the model is established by comprising an improved skin effect branch and a substrate lateral coupling branch. The parameter extraction is based on an improved characteristic function approach and vector fitting method. The model has better simulation than the previous work over the measured data of 2.5r and 4.5r on-chip inductors in the GaAs process.展开更多
The resonant excitation is used to generate photo-excited carriers in quantum wells to observe the process of the carriers transportation by comparing the photoluminescence results between quantum wells with and witho...The resonant excitation is used to generate photo-excited carriers in quantum wells to observe the process of the carriers transportation by comparing the photoluminescence results between quantum wells with and without a p-n junction. It is observed directly in experiment that most of the photo-excited carriers in quantum wells with a p-n junction escape from quantum wells and form photoeurrent rather than relax to the ground state of the quantum wells. The photo absorption coei^cient of multiple quantum wells is also enhanced by a p-n junction. The results pave a novel way for solar cells and photodetectors making use of low-dimensional structure.展开更多
Technologies are described for integrating multiple bandgaps and photonic crystal structures monolithically in a semiconductor chip. Practical devices examples include high power 980 nm pumps, 2×2 crosspoint swit...Technologies are described for integrating multiple bandgaps and photonic crystal structures monolithically in a semiconductor chip. Practical devices examples include high power 980 nm pumps, 2×2 crosspoint switches and lasers modelocked at THz frequencies.展开更多
基金China Postdoctoral Science Foundation (No.20090461048)Postdoctoral Science Foundation of Jiangsu Province (No.0901022C)Postdoctoral Science Foundation of Southeast University
文摘The characteristic impedances of L-type and T-type networks are first investigated for a distributed amplifier design.The analysis shows that the L-type network has better frequency characteristics than the T-type one.A distribution amplifier based on the L-type network is implemented with the 2-μm GaAs HBT（heterojunction-bipolar transistor） process of WIN semiconductors.The measurement result presents excellent bandwidth performance and gives a gain of 5.5 dB with a gain flatness of ±1dB over a frequency range from 3 to 18 GHz.The return losses S11 and S22 are below-10dB in the designed frequency range.The output 1-dB compression point at 5 GHz is 13.3 dBm.The chip area is 0.95 mm2 and the power dissipation is 95 mW under a 3.5 V supply.
基金Project supported by the National Natural Science Foundation of China(No.61674036)
文摘An improved single-π equivalent circuit model for on-chip inductors in the GaAs process is presented in this paper. Considering high order parasites, the model is established by comprising an improved skin effect branch and a substrate lateral coupling branch. The parameter extraction is based on an improved characteristic function approach and vector fitting method. The model has better simulation than the previous work over the measured data of 2.5r and 4.5r on-chip inductors in the GaAs process.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11574362,61210014,and 11374340the Innovative Clean-Energy Research and Application Program of Beijing Municipal Science and Technology Commission under Grant No Z151100003515001
文摘The resonant excitation is used to generate photo-excited carriers in quantum wells to observe the process of the carriers transportation by comparing the photoluminescence results between quantum wells with and without a p-n junction. It is observed directly in experiment that most of the photo-excited carriers in quantum wells with a p-n junction escape from quantum wells and form photoeurrent rather than relax to the ground state of the quantum wells. The photo absorption coei^cient of multiple quantum wells is also enhanced by a p-n junction. The results pave a novel way for solar cells and photodetectors making use of low-dimensional structure.
文摘Technologies are described for integrating multiple bandgaps and photonic crystal structures monolithically in a semiconductor chip. Practical devices examples include high power 980 nm pumps, 2×2 crosspoint switches and lasers modelocked at THz frequencies.
