A monolithic microwave integrated circuit （MMIC） power amplifier （PA） is proposed. It adopts a new on-chip bias circuit, which not only avoids the instability of the direct current bias caused by the change in the...A monolithic microwave integrated circuit （MMIC） power amplifier （PA） is proposed. It adopts a new on-chip bias circuit, which not only avoids the instability of the direct current bias caused by the change in the power supply and temperature, but also compensates deviations caused by the increase in input power. The bias circuit is a current-mirror configuration, and the feedback circuit helps to maintain bias voltage at a constant level. The gain of the feedback circuit is improved by the addition of a non-inverting amplifier within the feedback circuit. A shunt capacitor at the base node of the active bias transistor enhances the linearity of the PA. The chip is fabricated in an InGaP/GaAs heterojunction bipolar transistor （HBT） process. Measured results exhibit a 26. 6-dBm output compression point, 33.6% power-added efficiency （PAE） and - 40.2 dBc adjacent channel power ratio （ACPR） for wide-band code division multiple access （W-CDMA） applications.展开更多
S-band gain flattened distributed fiber Raman amplifier with a bandwidth from 1 488 nm to 1 541 nm （53 nm in width） ,an averaged gain of 10 dB and a gain ripple of ±0.6 dB is obtained successfully, in which a s...S-band gain flattened distributed fiber Raman amplifier with a bandwidth from 1 488 nm to 1 541 nm （53 nm in width） ,an averaged gain of 10 dB and a gain ripple of ±0.6 dB is obtained successfully, in which a single-wavelength high power fiber Raman laser with wavelength of 1 427.2 nm is used as the pump and the chirped fiber Bragg grating is used as the gain flattening filter. Besides,filter wavelength division multiplexer（FWDM） is used as the multi-signal multiplexer and 1 427 nm/1 505 nm coarse wavelength division multiplexer（OWDM） is used as the pump-signal coupler. The gain media are G652 fiber of 50 km in length and dispersion compensation fiber（DOF） of 5 km in length. Moreover, the location arrangements of different type of fibers and the effect caused by gain flattening filter as well as their solutions are discussed in detail. It is very significant to extend the range of optical fiber communication band and increase the capacity of fiber communication especially for ultra-long haul and ultra-high capacity communication system.展开更多
Semiconductor optical amplifiers (SOA) are optical amplifying devices and key parts in optical switches and optical buffers.They are largely used in communication system.Linewidth enhancement factor is an important pa...Semiconductor optical amplifiers (SOA) are optical amplifying devices and key parts in optical switches and optical buffers.They are largely used in communication system.Linewidth enhancement factor is an important parameter for SOA.A method is proposed to measure the linewidth enhancement factor with Sagnac interferometer.Cross phase modulation (XPM) and cross gain modulation (XGM) coexist in SOA.The quantitative relation of linewidth enhancement factor to XGM and the interference extinction ratio is given.The experimental results indicate that the value of linewidth enhancement factor changes from 5.13 to 6.24 when the electric current varies from 130 mA to 240 mA.展开更多
A semiconductor optical amplifier gate based on tensile strained quasi bulk InGaAs is developed.At injection current of 80mA,a 3dB optical bandwidth of more than 85nm is achieved due to dominant band filling effect...A semiconductor optical amplifier gate based on tensile strained quasi bulk InGaAs is developed.At injection current of 80mA,a 3dB optical bandwidth of more than 85nm is achieved due to dominant band filling effect.Moreover,the most important is that very low polarization dependence of gain (<0 7dB),fiber to fiber lossless operation current (70～90mA) and a high extinction ratio (>50dB) are simultaneously obtained over this wide 3dB optical bandwidth (1520～1609nm) which nearly covers the spectral region of the whole C band (1525～1565nm) and the whole L band (1570～1610nm).The gating time is also improved by decreasing carrier lifetime.The wide band polarization insensitive SOA gate is promising for use in future dense wavelength division multiplexing (DWDM) communication systems.展开更多
This work is about the development of a super low noise amplifier with minimum power consumption and high gain for several wireless applications.The amplifier operates at frequency bands of 0.9-2.4 GHz and can be used...This work is about the development of a super low noise amplifier with minimum power consumption and high gain for several wireless applications.The amplifier operates at frequency bands of 0.9-2.4 GHz and can be used in many applications like Wireless local area network(WLAN),WiFi,Bluetooth,ZigBee and Global System for mobile communications(GSM).This new design can be employed for the IEEE 802.15.4 standard in industrial,scientific and medical(ISM) Band.The enhancement mode pseudomorphic high electron mobility transistor PHEMT is used here due to its high linearity,better performance and less noisy operation.The common source inductive degeneration method is employed here to enhance the gain of amplifier.The amplifier produces a gain of more than 17 dB and noise figure of about 0.5 dB.The lower values of S11 and S22 reflect the accuracy of impedance matching network placed at the input and output sides of amplifier.Agilent Advance Design System(ADS) is used for the design and simulation purpose.Further the layout of design is developed on the FR4 substrate.展开更多
A wideband dual-feedback low noise amplifier （LNA） was analyzed, designed and implemented using SiGe heterojunction bipolar transistor （HBT） technology. The design analysis in terms of gain, input and output match...A wideband dual-feedback low noise amplifier （LNA） was analyzed, designed and implemented using SiGe heterojunction bipolar transistor （HBT） technology. The design analysis in terms of gain, input and output matching, noise and poles for the amplifier was presented in detail. The area of the complete chip die, including bonding pads and seal ring, was 655 μm × 495 μm. The on-wafer measurements on the fabricated wideband LNA sample demonstrated good performance： a small-signal power gain of 33 dB with 3-dB bandwidth at 3.3 GHz was achieved; the input and output return losses were better than - 10 dB from 100 MHz to 4 GHz and to 6 GHz, respectively; the noise figure was lower than 4.25 dB from 100 MHz to 6 GHz; with a 5 V supply, the values of OPtdB and OIP3 were 1.7 dBm and 11 dBm at 3-dB bandwidth, respectively.展开更多
In this paper, a novel structure of linear-in-dB gain control is introduced. Based on this structure, a wideband variable gain low noise amplifier （VGLNA） has been designed and implemented in 0.18μm RF CMOS technol...In this paper, a novel structure of linear-in-dB gain control is introduced. Based on this structure, a wideband variable gain low noise amplifier （VGLNA） has been designed and implemented in 0.18μm RF CMOS technology. The measured resuhs show a good linear-in-dB gain control characteristic with 15 dB dynamic range. It can operate in the frequency range of MHz and consumes 30mW from 1.8V power supply. The minimum noise figure is 4.1 dB at the 48 - 860 maximum gain and the input P1dB is greater than - 16.5dBm.展开更多
Objective： To investigate the feasibility of posterior fixation with 3.5-mm pedicle screws in the atlantoaxial vertebrae of children. Methods： In this study, atlantoaxial vertebrae specimens were obtained from 10 ca...Objective： To investigate the feasibility of posterior fixation with 3.5-mm pedicle screws in the atlantoaxial vertebrae of children. Methods： In this study, atlantoaxial vertebrae specimens were obtained from 10 cadavers of children aged 6-8 years. We measured the height and width of the C1 pedicle and the midportion of C1 lateral mass; the width of C1 posterior arch under the vertebral artery groove and the height of the external and internal one-third of this part; the external, internal height and the superior, middle, inferior width of the C2 pedicle （transverse foramen）. Furthermore, computed tomography （CT） axial scan was performed on 20 agematched volunteers to obtain relative data of their atlantoaxial vertebrae. We measured the length and width of the C1 and C2 pedicles in the atlantoaxial cross-sectional plane. On CT workstation, we also measured the angles between the longitudinal axes of the atlantoaxial pedicles and the midsagittal plane. Results： For the cadaveric specimen group, the height and width of the C1 pedicle were （5.26±0.44） mm and （6.26±0.75） mm respectively. The height of the medial one-third of the Ct posterior arch under the vertebral artery groove was （4.07±0.24） mm. The external, internal height and superior, middle, inferior width of the C2 pedicle was （6.86±0.48） mm, （6.67±0.49） mm, （6.63 ±0.61） mm, （5.41±0.39） mm and （3.71±0.30） mm, respectively. For the volunteer group measured by CT scan, the height and width of the C1 pedicle were （5.47 ±0.34） mm and （6.63±0.54） mm respectively, while （6.59±0.51） mm and （5.13 ±0.42） mm of the C2 pedicle. The angles between the atlas, axis pedicles and the midsagittal plane were （9.60±1.32）° and （27.80±2.22）° respectively. Conclusion： It is feasible to place a 3.5-mm pedicle screw in the C1 and C2 pedicles of children aged 6-8 years old.展开更多
基金The National High Technology Research and Development Program of China(863 Program)(No.2009AA01Z260)
文摘A monolithic microwave integrated circuit （MMIC） power amplifier （PA） is proposed. It adopts a new on-chip bias circuit, which not only avoids the instability of the direct current bias caused by the change in the power supply and temperature, but also compensates deviations caused by the increase in input power. The bias circuit is a current-mirror configuration, and the feedback circuit helps to maintain bias voltage at a constant level. The gain of the feedback circuit is improved by the addition of a non-inverting amplifier within the feedback circuit. A shunt capacitor at the base node of the active bias transistor enhances the linearity of the PA. The chip is fabricated in an InGaP/GaAs heterojunction bipolar transistor （HBT） process. Measured results exhibit a 26. 6-dBm output compression point, 33.6% power-added efficiency （PAE） and - 40.2 dBc adjacent channel power ratio （ACPR） for wide-band code division multiple access （W-CDMA） applications.
基金This work was supported bythe Great Scientific Research Projectof Zhejiang Province ,P.R.China (No.021101558)the Min-istry of Science and Technology ,Korea as a part of project fundsof the Korea-China Optical Technology Research Center .
文摘S-band gain flattened distributed fiber Raman amplifier with a bandwidth from 1 488 nm to 1 541 nm （53 nm in width） ,an averaged gain of 10 dB and a gain ripple of ±0.6 dB is obtained successfully, in which a single-wavelength high power fiber Raman laser with wavelength of 1 427.2 nm is used as the pump and the chirped fiber Bragg grating is used as the gain flattening filter. Besides,filter wavelength division multiplexer（FWDM） is used as the multi-signal multiplexer and 1 427 nm/1 505 nm coarse wavelength division multiplexer（OWDM） is used as the pump-signal coupler. The gain media are G652 fiber of 50 km in length and dispersion compensation fiber（DOF） of 5 km in length. Moreover, the location arrangements of different type of fibers and the effect caused by gain flattening filter as well as their solutions are discussed in detail. It is very significant to extend the range of optical fiber communication band and increase the capacity of fiber communication especially for ultra-long haul and ultra-high capacity communication system.
文摘Semiconductor optical amplifiers (SOA) are optical amplifying devices and key parts in optical switches and optical buffers.They are largely used in communication system.Linewidth enhancement factor is an important parameter for SOA.A method is proposed to measure the linewidth enhancement factor with Sagnac interferometer.Cross phase modulation (XPM) and cross gain modulation (XGM) coexist in SOA.The quantitative relation of linewidth enhancement factor to XGM and the interference extinction ratio is given.The experimental results indicate that the value of linewidth enhancement factor changes from 5.13 to 6.24 when the electric current varies from 130 mA to 240 mA.
文摘A semiconductor optical amplifier gate based on tensile strained quasi bulk InGaAs is developed.At injection current of 80mA,a 3dB optical bandwidth of more than 85nm is achieved due to dominant band filling effect.Moreover,the most important is that very low polarization dependence of gain (<0 7dB),fiber to fiber lossless operation current (70～90mA) and a high extinction ratio (>50dB) are simultaneously obtained over this wide 3dB optical bandwidth (1520～1609nm) which nearly covers the spectral region of the whole C band (1525～1565nm) and the whole L band (1570～1610nm).The gating time is also improved by decreasing carrier lifetime.The wide band polarization insensitive SOA gate is promising for use in future dense wavelength division multiplexing (DWDM) communication systems.
基金supported by the National Natural Science Foundation of China(Grant no. 61202399,61571063)
文摘This work is about the development of a super low noise amplifier with minimum power consumption and high gain for several wireless applications.The amplifier operates at frequency bands of 0.9-2.4 GHz and can be used in many applications like Wireless local area network(WLAN),WiFi,Bluetooth,ZigBee and Global System for mobile communications(GSM).This new design can be employed for the IEEE 802.15.4 standard in industrial,scientific and medical(ISM) Band.The enhancement mode pseudomorphic high electron mobility transistor PHEMT is used here due to its high linearity,better performance and less noisy operation.The common source inductive degeneration method is employed here to enhance the gain of amplifier.The amplifier produces a gain of more than 17 dB and noise figure of about 0.5 dB.The lower values of S11 and S22 reflect the accuracy of impedance matching network placed at the input and output sides of amplifier.Agilent Advance Design System(ADS) is used for the design and simulation purpose.Further the layout of design is developed on the FR4 substrate.
基金Supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China(No.2009ZX02303-003)
文摘A wideband dual-feedback low noise amplifier （LNA） was analyzed, designed and implemented using SiGe heterojunction bipolar transistor （HBT） technology. The design analysis in terms of gain, input and output matching, noise and poles for the amplifier was presented in detail. The area of the complete chip die, including bonding pads and seal ring, was 655 μm × 495 μm. The on-wafer measurements on the fabricated wideband LNA sample demonstrated good performance： a small-signal power gain of 33 dB with 3-dB bandwidth at 3.3 GHz was achieved; the input and output return losses were better than - 10 dB from 100 MHz to 4 GHz and to 6 GHz, respectively; the noise figure was lower than 4.25 dB from 100 MHz to 6 GHz; with a 5 V supply, the values of OPtdB and OIP3 were 1.7 dBm and 11 dBm at 3-dB bandwidth, respectively.
文摘In this paper, a novel structure of linear-in-dB gain control is introduced. Based on this structure, a wideband variable gain low noise amplifier （VGLNA） has been designed and implemented in 0.18μm RF CMOS technology. The measured resuhs show a good linear-in-dB gain control characteristic with 15 dB dynamic range. It can operate in the frequency range of MHz and consumes 30mW from 1.8V power supply. The minimum noise figure is 4.1 dB at the 48 - 860 maximum gain and the input P1dB is greater than - 16.5dBm.
文摘Objective： To investigate the feasibility of posterior fixation with 3.5-mm pedicle screws in the atlantoaxial vertebrae of children. Methods： In this study, atlantoaxial vertebrae specimens were obtained from 10 cadavers of children aged 6-8 years. We measured the height and width of the C1 pedicle and the midportion of C1 lateral mass; the width of C1 posterior arch under the vertebral artery groove and the height of the external and internal one-third of this part; the external, internal height and the superior, middle, inferior width of the C2 pedicle （transverse foramen）. Furthermore, computed tomography （CT） axial scan was performed on 20 agematched volunteers to obtain relative data of their atlantoaxial vertebrae. We measured the length and width of the C1 and C2 pedicles in the atlantoaxial cross-sectional plane. On CT workstation, we also measured the angles between the longitudinal axes of the atlantoaxial pedicles and the midsagittal plane. Results： For the cadaveric specimen group, the height and width of the C1 pedicle were （5.26±0.44） mm and （6.26±0.75） mm respectively. The height of the medial one-third of the Ct posterior arch under the vertebral artery groove was （4.07±0.24） mm. The external, internal height and superior, middle, inferior width of the C2 pedicle was （6.86±0.48） mm, （6.67±0.49） mm, （6.63 ±0.61） mm, （5.41±0.39） mm and （3.71±0.30） mm, respectively. For the volunteer group measured by CT scan, the height and width of the C1 pedicle were （5.47 ±0.34） mm and （6.63±0.54） mm respectively, while （6.59±0.51） mm and （5.13 ±0.42） mm of the C2 pedicle. The angles between the atlas, axis pedicles and the midsagittal plane were （9.60±1.32）° and （27.80±2.22）° respectively. Conclusion： It is feasible to place a 3.5-mm pedicle screw in the C1 and C2 pedicles of children aged 6-8 years old.
