In the field of intelligent education,the integration of artificial intelligence,especially deep learning technologies,has garnered significant attention.Knowledge tracing(KT)plays a pivotal role in this field by pred...In the field of intelligent education,the integration of artificial intelligence,especially deep learning technologies,has garnered significant attention.Knowledge tracing(KT)plays a pivotal role in this field by predicting students’future performance through the analysis of historical interaction data,thereby assisting educators in evaluating knowledgemastery and tailoring instructional strategies.Traditional knowledge tracingmethods,largely based on Recurrent Neural Networks(RNNs)and Transformer models,primarily focus on capturing long-term interaction patterns in sequential data.However,these models may neglect crucial short-term dynamics and other relevant features.This paper introduces a novel approach to knowledge tracing by leveraging a pure Multilayer Perceptron(MLP)architecture.We proposeMixerKT,a knowledge tracing model based on theHyperMixer framework,which uniquely integrates global and localMixer feature extractors.This architecture enables more effective extraction of both long-terminteraction trends and recent learning behaviors,addressing limitations in currentmodels thatmay overlook these key aspects.Empirical evaluations on twowidely-used datasets,ASSIS Tments2009 and Algebra2005,demonstrate that MixerKT consistently outperforms several state-of-the-art models,including DKT,SAKT,and Separated Self-Attentive Neural Knowledge Tracing(SAINT).Specifically,MixerKT achieves higher prediction accuracy,highlighting its effectiveness in capturing the nuances of learners’knowledge states.These results indicate that our model provides a more comprehensive representation of student learning patterns,enhancing the ability to predict future performance with greater precision.展开更多
Brain imaging is important in detecting Mild Cognitive Impairment(MCI)and related dementias.Magnetic Resonance Imaging(MRI)provides structural insights,while Positron Emission Tomography(PET)evaluates metabolic activi...Brain imaging is important in detecting Mild Cognitive Impairment(MCI)and related dementias.Magnetic Resonance Imaging(MRI)provides structural insights,while Positron Emission Tomography(PET)evaluates metabolic activity,aiding in the identification of dementia-related pathologies.This study integrates multiple data modalities—T1-weighted MRI,Pittsburgh Compound B(PiB)PET scans,cognitive assessments such as Mini-Mental State Examination(MMSE),Clinical Dementia Rating(CDR)and Functional Activities Questionnaire(FAQ),blood pressure parameters,and demographic data—to improve MCI detection.The proposed improved Convolutional Mixer architecture,incorporating B-cos modules,multi-head self-attention,and a custom classifier,achieves a classification accuracy of 96.3%on the Mayo Clinic Study of Aging(MCSA)dataset(sagittal plane),outperforming state-of-the-art models by 5%–20%.On the full dataset,the model maintains a high accuracy of 94.9%,with sensitivity and specificity reaching 89.1%and 98.3%,respectively.Extensive evaluations across different imaging planes confirm that the sagittal plane offers the highest diagnostic performance,followed by axial and coronal planes.Feature visualization highlights contributions from central brain structures and lateral ventricles in differentiating MCI from cognitively normal subjects.These results demonstrate that the proposed multimodal deep learning approach improves accuracy and interpretability in MCI detection.展开更多
The flow field and aerodynamic performances for the scarfed lobed forced mixer are studied based on a computational fluid dynamics（CFD） technique. A series of computations are conducted to obtain the effects of the ...The flow field and aerodynamic performances for the scarfed lobed forced mixer are studied based on a computational fluid dynamics（CFD） technique. A series of computations are conducted to obtain the effects of the bypass ratio and the scarf angle on the mixing performance for the scarfed lobed mixer. Results show that the scarfed lobed mixer is reduced in the system weight. Meanwhile, aerodynamic performances are slightly improved compared with the normal lobed mixer. Two reasons for causing the mixing enhancement between the core and the bypass flow are as follows： （1） The stream-wise vortices shed from the training edge of the half/full scarfed lobed mixer earlier is enhanced by about 25%. （2） The mixing augmentation is also associated with the increase of the interface length caused by scarfing. The thermal mixing efficiency is enhanced with the increase of the bypass ratio and the scarfing angle. The scarfed lobed mixer design has no negative effects on the pressure loss. The total pressure recovery coefficient reaches above 0. 935 in various bypass ratios and scarfed angles. As the bypass ratio increases, the total pressure recovery coefficient also increases for the scarfed lobed mixer.展开更多
A quadrature mixer with a shared transconductor stage is analyzed,including voltage conversion gain, linearity, noise figure, and image rejection. The analysis indicates it has better performance than a conventional G...A quadrature mixer with a shared transconductor stage is analyzed,including voltage conversion gain, linearity, noise figure, and image rejection. The analysis indicates it has better performance than a conventional Gilbert mixer pair in commutating mode. A quadrature down-conversion mixer based on this topology is designed and optimized for an ultra high frequency RFID reader. Operating in the 915MHz ISM band, the presented quadrature mixer measures a conversion gain of 12.5dB,an IIP3 of 10dBm, an IIP2 of 58dBm, and an SSB noise figure of 17.6riB. The chip was fabricated in a 0. 18μm 1P6M RF CMOS process and consumes only 3mA of current from a 1.8V power supply.展开更多
The folded-cascode structure is used to realize the low-voltage low-power consumption mixer, whose performance parameters have big influence on the navigation radio receiver＇s performance. Adopting the folded-cascode...The folded-cascode structure is used to realize the low-voltage low-power consumption mixer, whose performance parameters have big influence on the navigation radio receiver＇s performance. Adopting the folded-cascode structure, the folded-cascode mixer （FCM） has a lower power supply voltage of 1.2 V and realizes the design trade-offs among the high transconductance, high linearity and low noise. The difficulties of realizing the trade-offs between the linearity and noise performance, the linearity and conversion gain, the conversion gain and noise performance are reduced. Fabricated in an radio frequency （RF） 0.18 μm CMOS process, the FCM has an active area of about 200 μm ×150 μm and consumes approximate 3.9 mW. The test results show that the FCM features a conversion gain （Gc） of some 14.5 dB, an input 1 dB compression point （Pin-1dB） of almost -13 dBm and a dual sideband （DSB） noise figure of around 12 dB. The FCM can be applied to the navigation radio receivers and electronic systems for aviation and aerospace or other related fields.展开更多
Based on the analyses of the reported Gilbert mixers operating at low supply vol tage,a down-conversion mixer and an up-conversion mixer for 2.4GHz bluetooth transceiver are presented with the modified low voltage de...Based on the analyses of the reported Gilbert mixers operating at low supply vol tage,a down-conversion mixer and an up-conversion mixer for 2.4GHz bluetooth transceiver are presented with the modified low voltage design techniques,respe ctively.Feedback and current mirror techniques suitable for low voltage operatio n are used to improve the linearity of the up-conversion mixer,and folded-casc ode output stage is adopted to optimize the noise and conversion gain of the dow n-conversion mixer operating at low voltage.Based on 0.35μm CMOS technology,s imulations are performed with 2V supply voltage.The results show that 20dBm thir d-order intercept point (IIP3),87mV output signal amplitude are achieved for up -conversion mixer with about 3mA current;while 20dB conversion gain (CG),6.5nV /Hz input-referred noise,4.4dBm IIP3 are obtained for down-conversion mixer with about 3.5mA current.展开更多
A down-conversion mixer and an up-conversion mixer for 2.4GHz WLAN transceivers are presented.The down-conversion mixer uses a class-AB input stage to get high linearity and to realize input impedance matching and sin...A down-conversion mixer and an up-conversion mixer for 2.4GHz WLAN transceivers are presented.The down-conversion mixer uses a class-AB input stage to get high linearity and to realize input impedance matching and single-ended to differential conversion.The mixers are implemented in 0.18μm CMOS process.The measured results are given to show their performance.展开更多
We analyze a wide-band,high-linearity down-conversion mixer for cable receptions that is implemented in 0. 35μm SiGe BiCMOS technology. The bandwidth of the RF （radio frequency） input covers the range from 1 to 1.8...We analyze a wide-band,high-linearity down-conversion mixer for cable receptions that is implemented in 0. 35μm SiGe BiCMOS technology. The bandwidth of the RF （radio frequency） input covers the range from 1 to 1.8GHz. The measured input power at the - 1dB compression point of the mixer reaches ＋ 14.23dBm. The highest voltage conversion gain is 8. 31dB, while the lowest noise figure is 19.4dB. The power consumed is 54mW with a 5V supply. The test result of the down-conversion mixer is outlined.展开更多
In order to improve the bandwidth of the conventional sub-harmonic mixer, a broad-band, high intermediate frequency（IF） sub-harmonic mixer for W-band applications is proposed. Replacing the open and short stubs that...In order to improve the bandwidth of the conventional sub-harmonic mixer, a broad-band, high intermediate frequency（IF） sub-harmonic mixer for W-band applications is proposed. Replacing the open and short stubs that are used in the convertional sub-harmonic mixer with a broad-band band-pass filter and a low-pass filter, respectively, a wide operating frequency band is achieved. Furthermore, without the use of the edge-coupled band-pass filter at radio frequency（RF） port, the proposed structure can be realized by common hybrid microwave integrated circuit technology at W- band. The measured results show that the proposed subharmonic mixer can operate from 80 to 107.5 GHz for RF frequency and support up to 18 GHz for the IF bandwidth. Also, the measured results show that the single-sideband conversion loss is less than 13. 7 dB over the available RF frequency band, while the minimum conversion loss is about 9 dB at an RF of 92. 5 GHz and an 1F of 3 GHz. Thus, a large operating bandwidth performance at W-band can be achieved by the orooosed mixer.展开更多
A quadrature modulator and an up-conversion mixer for an 802. lla wireless LAN system are designed and fabricated in 0.18μm gate length standard CMOS technology. A current feedback loop with a transconductor is used ...A quadrature modulator and an up-conversion mixer for an 802. lla wireless LAN system are designed and fabricated in 0.18μm gate length standard CMOS technology. A current feedback loop with a transconductor is used to improve the linearity of the quadrature modulator;An LC resonant tank is used as the load of the upconversion mixer to improve its gain and increase the voltage swing. The measurement results show that the input P1dB achieves -3.6dBm, the transducer power gain of the circuit is -3.6dB,and the current consumes about 45.8mA with a 1.8V power supply.展开更多
A low noise, high conversion gain down-conversion mixer for WLAN 802.11a applications, which adopts the high intermediate frequency （IF） topology, is presented. The input radio frequency （RF）band, local oscillator...A low noise, high conversion gain down-conversion mixer for WLAN 802.11a applications, which adopts the high intermediate frequency （IF） topology, is presented. The input radio frequency （RF）band, local oscillator（LO）frequency band and output IF are 5.15 to 5.35, 4.15 to 4.35 and 1 GHz, respectively. Source resistive degeneration technique and pseudo-differential Gilbert topology are used to achieve high linearity, and, current bleeding technique and LC resonant loads are used to acquire a low noise figure. In addition, the mixer adopts a common-source transistor pair cross-stacked with a source follow pair（CSSF）circuit as an output buffer to enhance the mixer＇s conversion gain but not deteriorate the other performances. The mixer is implemented in 0.18 μm RF CMOS（complementary metal oxide semiconductor transistor）technology and the chip area of the mixer including all bonding pads is 580 μm×1 185 μm. The measured results show that under a 1.8 V supply, the conversion gain is 10.1 dB; the input 1 dB compression point and the input-referred third-order intercept point are-3.5 and 5.3 dBm, respectively; the single side band （SSB）noise figure （NF）is 8.65 dB, and the core current consumption is 3.8 mA.展开更多
In today's aircraft,the hardware redundancy is driven by the critical surfaces resulting in single point-failures.Reconfiguration technology remoVes the single surface criticality by employing control surfaces wit...In today's aircraft,the hardware redundancy is driven by the critical surfaces resulting in single point-failures.Reconfiguration technology remoVes the single surface criticality by employing control surfaces with aerodynamic redundancy.This paper studies a control reconfiguration scheme based on Control Mixer Concept.A technique for the design of a control mixer for an aircraft with damaged surfaces/actuators using the pseudo-inverse is developed and applied.This paper discusses its applications and limitations based on linear analysis and computer simulation.展开更多
A new architecture of CMOS low voltage downconve rsion mixer is presented.With 1.452GHz LO input and 1.45GHz RF input,simulation results show that the conversion gain is 15dB,IIP3 is -4.5dBm,NF is 17dB,the maximum tra...A new architecture of CMOS low voltage downconve rsion mixer is presented.With 1.452GHz LO input and 1.45GHz RF input,simulation results show that the conversion gain is 15dB,IIP3 is -4.5dBm,NF is 17dB,the maximum transient power dissipation is 9.3mW,and DC power dissipation is 9.2mW.The mixer’s noise and linearity analyses are also presented.展开更多
This paper presents the design and simulation of several fixed-tuned sub-harmonic mixers cover frequencies from 110 GH to 130 GHz, 215 GH to 235 GHz, 310 GH to 350 GHz, and 400 GH to 440 GHz. Among them, 120 GHz, 225 ...This paper presents the design and simulation of several fixed-tuned sub-harmonic mixers cover frequencies from 110 GH to 130 GHz, 215 GH to 235 GHz, 310 GH to 350 GHz, and 400 GH to 440 GHz. Among them, 120 GHz, 225 GHz, 330 GHz subharmonic mixers are designed with flip-chipped planar schottky diode mounted onto a suspended quartz-based substrate, the 225 GHz and 425 GHz subharmonic mixers are GaAs membrane integrated, and the 115 GHz subharmonic mixer has been fabricated and tested already.展开更多
Passive micromixers are preferred over active mixers for many microfluidic applications due to their relative ease in integration into complex systems and operational flexibility.They also incur very low cost of manuf...Passive micromixers are preferred over active mixers for many microfluidic applications due to their relative ease in integration into complex systems and operational flexibility.They also incur very low cost of manufacturing.However,the degree of mixing is comparatively low in passive mixers than active mixers due to the absence of disturbance in the flow by external forces and the inherent laminar nature of microchannel flows.Various designs of complex channel structures and three-dimensional geometries have been investigated in the past to obtain an efficient mixing in passive mixers.But the studies on mixing enhancement with simple planar geometries of passive mixers have been few and limited.The present work aims to investigate the possibility of mixing enhancement by employing simple planar type designs,such as T-mixer and T–T mixer with cylindrical elements placed in the mixing channel.The mixing performance has been evaluated in the Reynolds number range of 6 to700.Numerical results have shown that T–T mixer with cylindrical elements performed significantly well and obtained very good mixing quality over basic T-mixer for the entire range of Reynolds number(6 to 700).The device has also shown better mixing as compared to basic T–T mixer and T-mixer with cylindrical elements.A larger pair of vortices formed in the stagnation area due to the presence of a cylindrical element in the junction.Cylindrical elements downstream caused significant enhancement in mixing due to splitting and recombining action.The size of the cylindrical element in the T–T mixer has been optimized to obtain better mixing performance of the device.Remarkable improvement in mixing quality by T–T mixer with cylindrical elements has been obtained at the expense of small rise in pressure drop as compared to other passive designs considered in this study.Therefore,the current design of T–T mixer with cylindrical elements can act as an effective and simple passive mixing device for various micromixing applications.展开更多
基金supported by National Natural Science Foundation of China(Nos.62266054 and 62166050)Key Program of Fundamental Research Project of Yunnan Science and Technology Plan(No.202201AS070021)+2 种基金Yunnan Fundamental Research Projects(No.202401AT070122)Yunnan International Joint Research and Development Center of China-Laos-Thailand Educational Digitalization(No.202203AP140006)Scientific Research Foundation of Yunnan Provincial Department of Education(No.2024Y159).
文摘In the field of intelligent education,the integration of artificial intelligence,especially deep learning technologies,has garnered significant attention.Knowledge tracing(KT)plays a pivotal role in this field by predicting students’future performance through the analysis of historical interaction data,thereby assisting educators in evaluating knowledgemastery and tailoring instructional strategies.Traditional knowledge tracingmethods,largely based on Recurrent Neural Networks(RNNs)and Transformer models,primarily focus on capturing long-term interaction patterns in sequential data.However,these models may neglect crucial short-term dynamics and other relevant features.This paper introduces a novel approach to knowledge tracing by leveraging a pure Multilayer Perceptron(MLP)architecture.We proposeMixerKT,a knowledge tracing model based on theHyperMixer framework,which uniquely integrates global and localMixer feature extractors.This architecture enables more effective extraction of both long-terminteraction trends and recent learning behaviors,addressing limitations in currentmodels thatmay overlook these key aspects.Empirical evaluations on twowidely-used datasets,ASSIS Tments2009 and Algebra2005,demonstrate that MixerKT consistently outperforms several state-of-the-art models,including DKT,SAKT,and Separated Self-Attentive Neural Knowledge Tracing(SAINT).Specifically,MixerKT achieves higher prediction accuracy,highlighting its effectiveness in capturing the nuances of learners’knowledge states.These results indicate that our model provides a more comprehensive representation of student learning patterns,enhancing the ability to predict future performance with greater precision.
文摘Brain imaging is important in detecting Mild Cognitive Impairment(MCI)and related dementias.Magnetic Resonance Imaging(MRI)provides structural insights,while Positron Emission Tomography(PET)evaluates metabolic activity,aiding in the identification of dementia-related pathologies.This study integrates multiple data modalities—T1-weighted MRI,Pittsburgh Compound B(PiB)PET scans,cognitive assessments such as Mini-Mental State Examination(MMSE),Clinical Dementia Rating(CDR)and Functional Activities Questionnaire(FAQ),blood pressure parameters,and demographic data—to improve MCI detection.The proposed improved Convolutional Mixer architecture,incorporating B-cos modules,multi-head self-attention,and a custom classifier,achieves a classification accuracy of 96.3%on the Mayo Clinic Study of Aging(MCSA)dataset(sagittal plane),outperforming state-of-the-art models by 5%–20%.On the full dataset,the model maintains a high accuracy of 94.9%,with sensitivity and specificity reaching 89.1%and 98.3%,respectively.Extensive evaluations across different imaging planes confirm that the sagittal plane offers the highest diagnostic performance,followed by axial and coronal planes.Feature visualization highlights contributions from central brain structures and lateral ventricles in differentiating MCI from cognitively normal subjects.These results demonstrate that the proposed multimodal deep learning approach improves accuracy and interpretability in MCI detection.
基金Supported by the Civil Aviation Research Foundation of Nanjing University of Aeronautics and Astronautics~~
文摘The flow field and aerodynamic performances for the scarfed lobed forced mixer are studied based on a computational fluid dynamics（CFD） technique. A series of computations are conducted to obtain the effects of the bypass ratio and the scarf angle on the mixing performance for the scarfed lobed mixer. Results show that the scarfed lobed mixer is reduced in the system weight. Meanwhile, aerodynamic performances are slightly improved compared with the normal lobed mixer. Two reasons for causing the mixing enhancement between the core and the bypass flow are as follows： （1） The stream-wise vortices shed from the training edge of the half/full scarfed lobed mixer earlier is enhanced by about 25%. （2） The mixing augmentation is also associated with the increase of the interface length caused by scarfing. The thermal mixing efficiency is enhanced with the increase of the bypass ratio and the scarfing angle. The scarfed lobed mixer design has no negative effects on the pressure loss. The total pressure recovery coefficient reaches above 0. 935 in various bypass ratios and scarfed angles. As the bypass ratio increases, the total pressure recovery coefficient also increases for the scarfed lobed mixer.
文摘A quadrature mixer with a shared transconductor stage is analyzed,including voltage conversion gain, linearity, noise figure, and image rejection. The analysis indicates it has better performance than a conventional Gilbert mixer pair in commutating mode. A quadrature down-conversion mixer based on this topology is designed and optimized for an ultra high frequency RFID reader. Operating in the 915MHz ISM band, the presented quadrature mixer measures a conversion gain of 12.5dB,an IIP3 of 10dBm, an IIP2 of 58dBm, and an SSB noise figure of 17.6riB. The chip was fabricated in a 0. 18μm 1P6M RF CMOS process and consumes only 3mA of current from a 1.8V power supply.
文摘The folded-cascode structure is used to realize the low-voltage low-power consumption mixer, whose performance parameters have big influence on the navigation radio receiver＇s performance. Adopting the folded-cascode structure, the folded-cascode mixer （FCM） has a lower power supply voltage of 1.2 V and realizes the design trade-offs among the high transconductance, high linearity and low noise. The difficulties of realizing the trade-offs between the linearity and noise performance, the linearity and conversion gain, the conversion gain and noise performance are reduced. Fabricated in an radio frequency （RF） 0.18 μm CMOS process, the FCM has an active area of about 200 μm ×150 μm and consumes approximate 3.9 mW. The test results show that the FCM features a conversion gain （Gc） of some 14.5 dB, an input 1 dB compression point （Pin-1dB） of almost -13 dBm and a dual sideband （DSB） noise figure of around 12 dB. The FCM can be applied to the navigation radio receivers and electronic systems for aviation and aerospace or other related fields.
文摘Based on the analyses of the reported Gilbert mixers operating at low supply vol tage,a down-conversion mixer and an up-conversion mixer for 2.4GHz bluetooth transceiver are presented with the modified low voltage design techniques,respe ctively.Feedback and current mirror techniques suitable for low voltage operatio n are used to improve the linearity of the up-conversion mixer,and folded-casc ode output stage is adopted to optimize the noise and conversion gain of the dow n-conversion mixer operating at low voltage.Based on 0.35μm CMOS technology,s imulations are performed with 2V supply voltage.The results show that 20dBm thir d-order intercept point (IIP3),87mV output signal amplitude are achieved for up -conversion mixer with about 3mA current;while 20dB conversion gain (CG),6.5nV /Hz input-referred noise,4.4dBm IIP3 are obtained for down-conversion mixer with about 3.5mA current.
文摘A down-conversion mixer and an up-conversion mixer for 2.4GHz WLAN transceivers are presented.The down-conversion mixer uses a class-AB input stage to get high linearity and to realize input impedance matching and single-ended to differential conversion.The mixers are implemented in 0.18μm CMOS process.The measured results are given to show their performance.
文摘We analyze a wide-band,high-linearity down-conversion mixer for cable receptions that is implemented in 0. 35μm SiGe BiCMOS technology. The bandwidth of the RF （radio frequency） input covers the range from 1 to 1.8GHz. The measured input power at the - 1dB compression point of the mixer reaches ＋ 14.23dBm. The highest voltage conversion gain is 8. 31dB, while the lowest noise figure is 19.4dB. The power consumed is 54mW with a 5V supply. The test result of the down-conversion mixer is outlined.
基金Research Foundation of China ( No.9140A01020209JW0601)
文摘In order to improve the bandwidth of the conventional sub-harmonic mixer, a broad-band, high intermediate frequency（IF） sub-harmonic mixer for W-band applications is proposed. Replacing the open and short stubs that are used in the convertional sub-harmonic mixer with a broad-band band-pass filter and a low-pass filter, respectively, a wide operating frequency band is achieved. Furthermore, without the use of the edge-coupled band-pass filter at radio frequency（RF） port, the proposed structure can be realized by common hybrid microwave integrated circuit technology at W- band. The measured results show that the proposed subharmonic mixer can operate from 80 to 107.5 GHz for RF frequency and support up to 18 GHz for the IF bandwidth. Also, the measured results show that the single-sideband conversion loss is less than 13. 7 dB over the available RF frequency band, while the minimum conversion loss is about 9 dB at an RF of 92. 5 GHz and an 1F of 3 GHz. Thus, a large operating bandwidth performance at W-band can be achieved by the orooosed mixer.
文摘A quadrature modulator and an up-conversion mixer for an 802. lla wireless LAN system are designed and fabricated in 0.18μm gate length standard CMOS technology. A current feedback loop with a transconductor is used to improve the linearity of the quadrature modulator;An LC resonant tank is used as the load of the upconversion mixer to improve its gain and increase the voltage swing. The measurement results show that the input P1dB achieves -3.6dBm, the transducer power gain of the circuit is -3.6dB,and the current consumes about 45.8mA with a 1.8V power supply.
基金The Science and Technology Program of Zhejiang Province (No.2008C16017)
文摘A low noise, high conversion gain down-conversion mixer for WLAN 802.11a applications, which adopts the high intermediate frequency （IF） topology, is presented. The input radio frequency （RF）band, local oscillator（LO）frequency band and output IF are 5.15 to 5.35, 4.15 to 4.35 and 1 GHz, respectively. Source resistive degeneration technique and pseudo-differential Gilbert topology are used to achieve high linearity, and, current bleeding technique and LC resonant loads are used to acquire a low noise figure. In addition, the mixer adopts a common-source transistor pair cross-stacked with a source follow pair（CSSF）circuit as an output buffer to enhance the mixer＇s conversion gain but not deteriorate the other performances. The mixer is implemented in 0.18 μm RF CMOS（complementary metal oxide semiconductor transistor）technology and the chip area of the mixer including all bonding pads is 580 μm×1 185 μm. The measured results show that under a 1.8 V supply, the conversion gain is 10.1 dB; the input 1 dB compression point and the input-referred third-order intercept point are-3.5 and 5.3 dBm, respectively; the single side band （SSB）noise figure （NF）is 8.65 dB, and the core current consumption is 3.8 mA.
文摘In today's aircraft,the hardware redundancy is driven by the critical surfaces resulting in single point-failures.Reconfiguration technology remoVes the single surface criticality by employing control surfaces with aerodynamic redundancy.This paper studies a control reconfiguration scheme based on Control Mixer Concept.A technique for the design of a control mixer for an aircraft with damaged surfaces/actuators using the pseudo-inverse is developed and applied.This paper discusses its applications and limitations based on linear analysis and computer simulation.
文摘A new architecture of CMOS low voltage downconve rsion mixer is presented.With 1.452GHz LO input and 1.45GHz RF input,simulation results show that the conversion gain is 15dB,IIP3 is -4.5dBm,NF is 17dB,the maximum transient power dissipation is 9.3mW,and DC power dissipation is 9.2mW.The mixer’s noise and linearity analyses are also presented.
基金supported by the National Natural Science Foundation of China under Grant No.61301051
文摘This paper presents the design and simulation of several fixed-tuned sub-harmonic mixers cover frequencies from 110 GH to 130 GHz, 215 GH to 235 GHz, 310 GH to 350 GHz, and 400 GH to 440 GHz. Among them, 120 GHz, 225 GHz, 330 GHz subharmonic mixers are designed with flip-chipped planar schottky diode mounted onto a suspended quartz-based substrate, the 225 GHz and 425 GHz subharmonic mixers are GaAs membrane integrated, and the 115 GHz subharmonic mixer has been fabricated and tested already.
文摘Passive micromixers are preferred over active mixers for many microfluidic applications due to their relative ease in integration into complex systems and operational flexibility.They also incur very low cost of manufacturing.However,the degree of mixing is comparatively low in passive mixers than active mixers due to the absence of disturbance in the flow by external forces and the inherent laminar nature of microchannel flows.Various designs of complex channel structures and three-dimensional geometries have been investigated in the past to obtain an efficient mixing in passive mixers.But the studies on mixing enhancement with simple planar geometries of passive mixers have been few and limited.The present work aims to investigate the possibility of mixing enhancement by employing simple planar type designs,such as T-mixer and T–T mixer with cylindrical elements placed in the mixing channel.The mixing performance has been evaluated in the Reynolds number range of 6 to700.Numerical results have shown that T–T mixer with cylindrical elements performed significantly well and obtained very good mixing quality over basic T-mixer for the entire range of Reynolds number(6 to 700).The device has also shown better mixing as compared to basic T–T mixer and T-mixer with cylindrical elements.A larger pair of vortices formed in the stagnation area due to the presence of a cylindrical element in the junction.Cylindrical elements downstream caused significant enhancement in mixing due to splitting and recombining action.The size of the cylindrical element in the T–T mixer has been optimized to obtain better mixing performance of the device.Remarkable improvement in mixing quality by T–T mixer with cylindrical elements has been obtained at the expense of small rise in pressure drop as compared to other passive designs considered in this study.Therefore,the current design of T–T mixer with cylindrical elements can act as an effective and simple passive mixing device for various micromixing applications.
