Effects of performing an R-factor analysis of observed variables based on population models comprising R- and Q-factors were investigated. Although R-factor analysis of data based on a population model comprising R- a...Effects of performing an R-factor analysis of observed variables based on population models comprising R- and Q-factors were investigated. Although R-factor analysis of data based on a population model comprising R- and Q-factors is possible, this may lead to model error. Accordingly, loading estimates resulting from R-factor analysis of sample data drawn from a population based on a combination of R- and Q-factors will be biased. It was shown in a simulation study that a large amount of Q-factor variance induces an increase in the variation of R-factor loading estimates beyond the chance level. Tests of the multivariate kurtosis of observed variables are proposed as an indicator of possible Q-factor variance in observed variables as a prerequisite for R-factor analysis.展开更多
Background: Q-Factor(QF), or the inter-pedal width, in cycling is similar to step-width in gait. Although increased step-width has been shown to reduce peak knee abduction moment(KAbM), no studies have examined the bi...Background: Q-Factor(QF), or the inter-pedal width, in cycling is similar to step-width in gait. Although increased step-width has been shown to reduce peak knee abduction moment(KAbM), no studies have examined the biomechanical effects of increased QF in cycling at different workrates in healthy participants.Methods: A total of 16 healthy participants(8 males, 8 females, age: 22.4 ± 2.6 years, body mass index: 22.78 ± 1.43 kg/m^2, mean ± SD) participated.A motion capture system and customized instrumented pedals were used to collect 3-dimensional kinematic(240 Hz) and pedal reaction force(PRF)(1200 Hz) data in 12 testing conditions: 4 QF conditions—Q1(15.0 cm), Q2(19.2 cm), Q3(23.4 cm), and Q4(27.6 cm)—under 3 workrate conditions—80 watts(W), 120 W, and 160 W. A 3 × 4(QF × workrate) repeated measures of analysis of variance were performed to analyze differences among conditions(p < 0.05).Results: Increased QF increased peak KAbM by 47%, 56%, and 56% from Q1 to Q4 at each respective workrate. Mediolateral PRF increased from Q1 to Q4 at each respective workrate. Frontal-plane knee angle and range of motion decreased with increased QF. No changes were observed for peak vertical PRF, knee extension moment, sagittal plane peak knee joint angles, or range of motion.Conclusion: Increased QF increased peak KAbM, suggesting increased medial compartment loading of the knee. QF modulation may influence frontal-plane joint loading when using stationary cycling for exercise or rehabilitation purposes.展开更多
The Q-factor is an important physical parameter for characterizing the absorption and attenuation of seismic waves propagating in underground media,which is of great signifi cance for improving the resolution of seism...The Q-factor is an important physical parameter for characterizing the absorption and attenuation of seismic waves propagating in underground media,which is of great signifi cance for improving the resolution of seismic data,oil and gas detection,and reservoir description.In this paper,the local centroid frequency is defi ned using shaping regularization and used to estimate the Q values of the formation.We propose a continuous time-varying Q-estimation method in the time-frequency domain according to the local centroid frequency,namely,the local centroid frequency shift(LCFS)method.This method can reasonably reduce the calculation error caused by the low accuracy of the time picking of the target formation in the traditional methods.The theoretical and real seismic data processing results show that the time-varying Q values can be accurately estimated using the LCFS method.Compared with the traditional Q-estimation methods,this method does not need to extract the top and bottom interfaces of the target formation;it can also obtain relatively reasonable Q values when there is no eff ective frequency spectrum information.Simultaneously,a reasonable inverse Q fi ltering result can be obtained using the continuous time-varying Q values.展开更多
With the advancement of photonic integration technology,ultra-low linewidth frequency-stabilized lasers have demonstrated significant potential in precision measurement,quantum communication,atomic clocks,etc.This rev...With the advancement of photonic integration technology,ultra-low linewidth frequency-stabilized lasers have demonstrated significant potential in precision measurement,quantum communication,atomic clocks,etc.This review summarizes the latest developments in integrated photonics for achieving ultra-low linewidth lasers,particularly breakthroughs made by integrating Brillouin lasers.We discuss the design principles,manufacturing processes,performance characteristics,and potential value of these lasers in various applications.展开更多
Under the conditions of strong sea clutter and complex moving targets,it is extremely difficult to detect moving targets in the maritime surface.This paper proposes a new algorithm named improved tunable Q-factor wave...Under the conditions of strong sea clutter and complex moving targets,it is extremely difficult to detect moving targets in the maritime surface.This paper proposes a new algorithm named improved tunable Q-factor wavelet transform(TQWT)for moving target detection.Firstly,this paper establishes a moving target model and sparsely compensates the Doppler migration of the moving target in the fractional Fourier transform(FRFT)domain.Then,TQWT is adopted to decompose the signal based on the discrimination between the sea clutter and the target’s oscillation characteristics,using the basis pursuit denoising(BPDN)algorithm to get the wavelet coefficients.Furthermore,an energy selection method based on the optimal distribution of sub-bands energy is proposed to sparse the coefficients and reconstruct the target.Finally,experiments on the Council for Scientific and Industrial Research(CSIR)dataset indicate the performance of the proposed method and provide the basis for subsequent target detection.展开更多
A novel tunable-quality-factor （tunable-Q） contourlet transform for geometric image representation is proposed. The Laplacian pyramid in original contourlet decomposes a signal into channels that have the same bandw...A novel tunable-quality-factor （tunable-Q） contourlet transform for geometric image representation is proposed. The Laplacian pyramid in original contourlet decomposes a signal into channels that have the same bandwidth on a logarithmic scale, and is not suitable for images with different behavior in frequency domain. We employ a new tunable-Q decomposition defined in the frequency domain by which one can flexibly tune the bandwidth of decomposition channels. With an acceptable redundancy, this tunable-Q contourlet is also anti-aliasing and its basis is sharply localized in the desired area of frequency and spatial domain. Our experiments in nonlinear approximation and denoising show that the contourlet using a better-suitable quality factor can achieve a more promising performance and often outperform wavelets and the previous contourlets both in visual quality and in terms of peak signal-to-noise ratio.展开更多
A nearly perfect metamaterial absorber is proposed that can find utility in terahertz sensing applications.The design consists of two concentric elliptical ring resonators(ERRs)whose parameters are appropriately set t...A nearly perfect metamaterial absorber is proposed that can find utility in terahertz sensing applications.The design consists of two concentric elliptical ring resonators(ERRs)whose parameters are appropriately set to achieve dual band absorption with near perfect absorption.The first absorption band at 3.62 THz having a Q-factor of 51.7 was caused due to the currents in the outer and inner ERR.The second absorption peak at 3.814 THz having a Q factor of 1411.11 was a consequence of currents flowing across the gap between the two concentric resonators.Furthermore,it is observed that the absorption bands are sensitive to the variation in refractive index of the surrounding medium.The sensitivity's in the absorption bands are 3 THz/RIU and 3.59 THz/RIU respectively.A sensor is proposed based on this design to detect harmful gases,which is demonstrated for detection of Methane and Chloroform.High Q-factor and high sensitivity of the narrow band makes the design an excellent sensor for detecting variations in the refractive index.展开更多
Analyzing the influence on Q factor, which was caused by the parasitic effect in a CMOS RF on chip integrated inductor, a concise method to increase the Q factor has been obtained when optimizing the layout parameter....Analyzing the influence on Q factor, which was caused by the parasitic effect in a CMOS RF on chip integrated inductor, a concise method to increase the Q factor has been obtained when optimizing the layout parameter. Using this method, the Q factor of 7.9 can be achieved in a 5nH inductor (operating frequency is 2GHz) while the errors in inductance are less than 0.5% compared with the aimed values. It is proved by experiments that this method can guarantee the sufficient accuracy but require less computation time. Therefore, it is of great use for the design of the inductor in CMOS RF IC’s.展开更多
In this paper, we present a three-dimensional（3D） vacuum packaging technique at a wafer level for a radio frequency micro-electromechanical system（RF MEMS） resonator, in which low-loss silicon vias is used to tran...In this paper, we present a three-dimensional（3D） vacuum packaging technique at a wafer level for a radio frequency micro-electromechanical system（RF MEMS） resonator, in which low-loss silicon vias is used to transmit RF signals.Au–Sn solder bonding is adopted to provide a vacuum encapsulation as well as electrical conductions. A RF model of the encapsulation cap is established to evaluate the parasitic effect of the packaging, which provides an effective design solution of 3D RF MEMS encapsulation. With the proposed packaging structure, the signal-to-background ratio（SBR） of 24 dB is achieved, as well as the quality factor（Q-factor） of the resonator increases from 8000 to 10400 after packaging.The packaged resonator has a linear frequency–temperature（ f –T） characteristic in a temperature range between 0℃ and 100℃. And the package shows favorable long-term stability of the Q-factor over 200 days, which indicates that the package has excellent hermeticity. Furthermore, the average shear strength is measured to be 43.58 MPa among 10 samples.展开更多
An increase in the demand of broadband service has encouraged research and study to find a solution to offer an adequate amount of service. Living in this digital world with downloading video, voice or data leads us o...An increase in the demand of broadband service has encouraged research and study to find a solution to offer an adequate amount of service. Living in this digital world with downloading video, voice or data leads us occasionally to have a shortage of bandwidth in the provided data. One of the solutions to cover the huge expected demand in the future is improving the communication systems by adding optical passive components to the Radio over Fiber (RoF) system. This work is mainly to increase the bandwidth that allows the small and single consumer at the last mile. We have shown that by adding the 40-GHz mm-wave to the system, Bit-Error-Rate (BER) has increased while Q-factor has decreased.展开更多
Two micromachined solenoid-type inductors with different electroplated core structures, ellipse and rectangle, were fabricated, tested and compared in order to reach optimum designs for integrated induetoes and transf...Two micromachined solenoid-type inductors with different electroplated core structures, ellipse and rectangle, were fabricated, tested and compared in order to reach optimum designs for integrated induetoes and transformers. In the process of fabrication, UV-LIGA, dry. etching technique, fine polishing and eleetroplating techniques have been adopted to achieve high performance mieminduetor. Experimental results show that both types of the induetors are characterized by high inductance, Q-factor and low electrical resistance. While the inductance of the inductor with rectangular magnetic core is slightly higher than that with elliptical magnetic core, the quality factor of the latter is larger than that of the former.展开更多
This paper describes a method for decomposing a signal into the sum of an oscillatory component and a transient component. The process uses the tunable Q-factor wavelet transform (TQWT): The oscillatory component is m...This paper describes a method for decomposing a signal into the sum of an oscillatory component and a transient component. The process uses the tunable Q-factor wavelet transform (TQWT): The oscillatory component is modeled as a signal that can be sparsely denoted by high Q-factor TQWT;similarly, the transient component is modeled as a piecewise smooth signal that can be sparsely denoted using low Q-factor TQWT. Since the low and high Q-factor TQWT has low coherence, the morphological component analysis (MCA) can effectively decompose the signal into oscillatory and transient components. The corresponding optimization problem of MCA is resolved by the split augmented Lagrangian shrinkage algorithm (SALSA). The applications of the proposed method to speech, electroencephalo-graph (EEG), and electrocardiograph (ECG) signals are included.展开更多
This technical paper presents a fundamental approach for design and optimization of a spiral inductor using ASITIC(analysis and simulation of spiral inductors and transformers for ICs)and SpiralCalc(integrated spiral ...This technical paper presents a fundamental approach for design and optimization of a spiral inductor using ASITIC(analysis and simulation of spiral inductors and transformers for ICs)and SpiralCalc(integrated spiral inductor calculator).Both tools are available for research and non-commercial purposes.Inductors are key components esp.for impedance matching and are designed such that they would exhibit a high Q-factor(quality-factor)for the specific inductance and frequency range of operation.A sample value of 5.3 nH is set for this paper for the spiral inductor design using the tools.For optimum Q-factor,an octagonal geometry for spiral inductor is used for ASITIC design,to have a close comparison to that of the SpiralCalc.Design methodologies for the optimization of the spiral inductor parameters such as the inductance and the Q-factor are discussed.Results comparison between the two tools is also presented.Design tradeoffs between inductor parameters are inevitable,and these parameters affect the performance of the inductor esp.at higher frequencies.With this,it is crucial that inductors be designed carefully for their effective frequency range of operation and specific requirements of the intended application.展开更多
In the face of deteriorating environmental conditions in the world,water quality control is an urgent task.It can be solved by creating sensors with high accuracy and low cost,which requires the development of fundame...In the face of deteriorating environmental conditions in the world,water quality control is an urgent task.It can be solved by creating sensors with high accuracy and low cost,which requires the development of fundamentally new radiophysical methods that take advantage of the optical,microwave and millimeter wavelengths that have a significantly greater sensitivity to low concentrations of pollutants and a lower inertia.The article presents prototypes of measuring cells of the microwave and optical ranges as well as the results of an experimental study of water of various degrees of pollution with their help.The results show that the use of the highly sensitive method of capillary-waveguide resonance makes it possible to detect the presence of micro impurities in water with concentrations up to0.1%and to identify water even from sources of various natural origins.In addition,the use of measurements at several frequencies in the optical range will make it possible to solve the problem of creating water control sensors with high sensitivity to pollution and low cost.It can be concluded that the possibility of complex use of multiwave sensors(optical,infrared and microwave ranges)allows to increase the sensitivity and reliability of water quality assessment.展开更多
New methods of an automated evaluation of the blood rheological parameters: 1) the viscosity, 2) electric conductivity and 3) the charge of erythrocytes have been theoretically and experimentally substantiated by way ...New methods of an automated evaluation of the blood rheological parameters: 1) the viscosity, 2) electric conductivity and 3) the charge of erythrocytes have been theoretically and experimentally substantiated by way of registering the Q-factor of the tuned-circuit, containing a capillary with the blood flow. A design of an electronic measuring complex is based on modeling the physical blood conditions in the natural environment.展开更多
Commercially available niobium (V) oxide [Nb2O5], with barium acetate [Ba(CH3COO)2] and magnesium acetate [Mg(CH3COO)2-4H2O] was used as the starting material in the sol-gel process for preparing Ba(Mg1/3Nb2/3)O3 (BMN...Commercially available niobium (V) oxide [Nb2O5], with barium acetate [Ba(CH3COO)2] and magnesium acetate [Mg(CH3COO)2-4H2O] was used as the starting material in the sol-gel process for preparing Ba(Mg1/3Nb2/3)O3 (BMN) nanopowders. At first, Nb2O5 reacted with melting sodium hydroxide and transformed into dispersible oxide. The resulting glassy substance after cooling was dispersed and washed several times in distilled water to remove the Na+ ions. The as-prepared colloidal Nb2O5-nH2O was subsequently mixed with acetic solution of barium acetate and magnesium acetate according to the required molar proportions and followed by gelation. The ultrafine BMN powders were finally obtained after heat-treating the gel at 820℃for 1 h, and the as-sintered nanoceramics revealed a high relative density of 98.2%, and a high microwave Q-factor, of 10397 at 1.45GHz.展开更多
Commercially available niobium (V) oxide [Nb_2O_5], with barium acetate[Ba(CH_3COO)_2] and magnesium acetate [Mg(CH_3COO)_2·4H_2O] was used as the starting material inthe sol-gel process for preparing Ba(Mg_(1/3)...Commercially available niobium (V) oxide [Nb_2O_5], with barium acetate[Ba(CH_3COO)_2] and magnesium acetate [Mg(CH_3COO)_2·4H_2O] was used as the starting material inthe sol-gel process for preparing Ba(Mg_(1/3)Nb_(2/3))O_3 (BMN) nanopowders. At first, Nb_2O_5reacted with melting sodium hydroxide and transformed into dispersible oxide. The resulting glassysubstance after cooling was dispersed and washed several times in distilled water to remove the Na^+ions. The as-prepared colloidal Nb_2O_5·nH_2O was subsequently mixed with acetic solution ofbarium acetate and magnesium acetate according to the required molar proportions and followed bygelation. The ultrafine BMN powders were finally obtained after heat-treating the gel at 820℃ for 1h, and the as-sintered nanoceramics revealed a high relative density of 98.2%, and a high microwaveQ-factor, of 10397 at 1,45GHz.展开更多
Fault diagnosis of rotating machinery is of great importance to the high quality products and long-term safe operation.However,the useful weak features are usually corrupted by strong background noise,thus increasing ...Fault diagnosis of rotating machinery is of great importance to the high quality products and long-term safe operation.However,the useful weak features are usually corrupted by strong background noise,thus increasing the difficulty of the feature extraction.Thereby,a novel denoising method based on the tunable Q-factor wavelet transform(TQWT)using neighboring coefficients is proposed in this article.The emerging TQWT possesses excellent properties compared with the conventional constant-Q wavelet transforms,which can tune Q-factor according to the oscillatory behavior of the signal.Meanwhile,neighboring coefficients denoising is adopted to avoid the overkill of conventional term-by-term thresholding techniques.Because of having the combined advantages of the two methods,the presented denoising method is more practical and effective than other methods.The proposed method is applied to a simulated signal,a rolling element bearing with an outer race defect from antenna transmission chain and a gearbox fault detection case.The processing results demonstrate that the proposed method can successfully identify the fault features,showing that this method is more effective than the conventional wavelet thresholding denoising methods,term-by-term TQWT denoising schemes and spectral kurtosis.展开更多
Phonon polariton resonances in the mid-infrared spectral range demonstrate properties superior to noble metal-based plasmonics,owing to smaller dissipative loss and better field confinement.However,a conventional way ...Phonon polariton resonances in the mid-infrared spectral range demonstrate properties superior to noble metal-based plasmonics,owing to smaller dissipative loss and better field confinement.However,a conventional way to excite the localized phonon resonance involves ion etching,which reduces the attainable quality factors(Q-factors)of the resonators.We show that by introducing a deep subwavelength layer of dielectric gratings on a phononic substrate,localized dipolar resonance and higher order modes with high Q-factors 96 and 195,respectively,can be excited.We further demonstrate,via experiments and simulations,that the resonant wavelength and field confinement can be controlled by coupling the localized hybrid mode with propagating surface phonon-polaritons.We also observed for the first time the coupling between a localized dipolar mode and a propagating higher-order surface phonon-polariton mode.The results will be useful in designing on-chip,low-loss,and highly integrated phononic devices in the infrared spectral domain.展开更多
文摘Effects of performing an R-factor analysis of observed variables based on population models comprising R- and Q-factors were investigated. Although R-factor analysis of data based on a population model comprising R- and Q-factors is possible, this may lead to model error. Accordingly, loading estimates resulting from R-factor analysis of sample data drawn from a population based on a combination of R- and Q-factors will be biased. It was shown in a simulation study that a large amount of Q-factor variance induces an increase in the variation of R-factor loading estimates beyond the chance level. Tests of the multivariate kurtosis of observed variables are proposed as an indicator of possible Q-factor variance in observed variables as a prerequisite for R-factor analysis.
文摘Background: Q-Factor(QF), or the inter-pedal width, in cycling is similar to step-width in gait. Although increased step-width has been shown to reduce peak knee abduction moment(KAbM), no studies have examined the biomechanical effects of increased QF in cycling at different workrates in healthy participants.Methods: A total of 16 healthy participants(8 males, 8 females, age: 22.4 ± 2.6 years, body mass index: 22.78 ± 1.43 kg/m^2, mean ± SD) participated.A motion capture system and customized instrumented pedals were used to collect 3-dimensional kinematic(240 Hz) and pedal reaction force(PRF)(1200 Hz) data in 12 testing conditions: 4 QF conditions—Q1(15.0 cm), Q2(19.2 cm), Q3(23.4 cm), and Q4(27.6 cm)—under 3 workrate conditions—80 watts(W), 120 W, and 160 W. A 3 × 4(QF × workrate) repeated measures of analysis of variance were performed to analyze differences among conditions(p < 0.05).Results: Increased QF increased peak KAbM by 47%, 56%, and 56% from Q1 to Q4 at each respective workrate. Mediolateral PRF increased from Q1 to Q4 at each respective workrate. Frontal-plane knee angle and range of motion decreased with increased QF. No changes were observed for peak vertical PRF, knee extension moment, sagittal plane peak knee joint angles, or range of motion.Conclusion: Increased QF increased peak KAbM, suggesting increased medial compartment loading of the knee. QF modulation may influence frontal-plane joint loading when using stationary cycling for exercise or rehabilitation purposes.
基金This work was supported by The National Key Research and Development Program(No.2016YFC0600505 and 2018YFC0603701)National Natural Science Foundation(No.41974134 and 41774127).
文摘The Q-factor is an important physical parameter for characterizing the absorption and attenuation of seismic waves propagating in underground media,which is of great signifi cance for improving the resolution of seismic data,oil and gas detection,and reservoir description.In this paper,the local centroid frequency is defi ned using shaping regularization and used to estimate the Q values of the formation.We propose a continuous time-varying Q-estimation method in the time-frequency domain according to the local centroid frequency,namely,the local centroid frequency shift(LCFS)method.This method can reasonably reduce the calculation error caused by the low accuracy of the time picking of the target formation in the traditional methods.The theoretical and real seismic data processing results show that the time-varying Q values can be accurately estimated using the LCFS method.Compared with the traditional Q-estimation methods,this method does not need to extract the top and bottom interfaces of the target formation;it can also obtain relatively reasonable Q values when there is no eff ective frequency spectrum information.Simultaneously,a reasonable inverse Q fi ltering result can be obtained using the continuous time-varying Q values.
基金This research is partially funded by the Natural Science Foundation of China Project under Grant Nos.61925104 and 62031011the Key Re⁃search and Development Program of Jiangsu Province under Grant No.BE2021008-5.
文摘With the advancement of photonic integration technology,ultra-low linewidth frequency-stabilized lasers have demonstrated significant potential in precision measurement,quantum communication,atomic clocks,etc.This review summarizes the latest developments in integrated photonics for achieving ultra-low linewidth lasers,particularly breakthroughs made by integrating Brillouin lasers.We discuss the design principles,manufacturing processes,performance characteristics,and potential value of these lasers in various applications.
基金the National Natural Science Foundation of China(U19B2031).
文摘Under the conditions of strong sea clutter and complex moving targets,it is extremely difficult to detect moving targets in the maritime surface.This paper proposes a new algorithm named improved tunable Q-factor wavelet transform(TQWT)for moving target detection.Firstly,this paper establishes a moving target model and sparsely compensates the Doppler migration of the moving target in the fractional Fourier transform(FRFT)domain.Then,TQWT is adopted to decompose the signal based on the discrimination between the sea clutter and the target’s oscillation characteristics,using the basis pursuit denoising(BPDN)algorithm to get the wavelet coefficients.Furthermore,an energy selection method based on the optimal distribution of sub-bands energy is proposed to sparse the coefficients and reconstruct the target.Finally,experiments on the Council for Scientific and Industrial Research(CSIR)dataset indicate the performance of the proposed method and provide the basis for subsequent target detection.
基金supported by the National Natural Science Foundation of China(4097117341071188)
文摘A novel tunable-quality-factor （tunable-Q） contourlet transform for geometric image representation is proposed. The Laplacian pyramid in original contourlet decomposes a signal into channels that have the same bandwidth on a logarithmic scale, and is not suitable for images with different behavior in frequency domain. We employ a new tunable-Q decomposition defined in the frequency domain by which one can flexibly tune the bandwidth of decomposition channels. With an acceptable redundancy, this tunable-Q contourlet is also anti-aliasing and its basis is sharply localized in the desired area of frequency and spatial domain. Our experiments in nonlinear approximation and denoising show that the contourlet using a better-suitable quality factor can achieve a more promising performance and often outperform wavelets and the previous contourlets both in visual quality and in terms of peak signal-to-noise ratio.
文摘A nearly perfect metamaterial absorber is proposed that can find utility in terahertz sensing applications.The design consists of two concentric elliptical ring resonators(ERRs)whose parameters are appropriately set to achieve dual band absorption with near perfect absorption.The first absorption band at 3.62 THz having a Q-factor of 51.7 was caused due to the currents in the outer and inner ERR.The second absorption peak at 3.814 THz having a Q factor of 1411.11 was a consequence of currents flowing across the gap between the two concentric resonators.Furthermore,it is observed that the absorption bands are sensitive to the variation in refractive index of the surrounding medium.The sensitivity's in the absorption bands are 3 THz/RIU and 3.59 THz/RIU respectively.A sensor is proposed based on this design to detect harmful gases,which is demonstrated for detection of Methane and Chloroform.High Q-factor and high sensitivity of the narrow band makes the design an excellent sensor for detecting variations in the refractive index.
文摘Analyzing the influence on Q factor, which was caused by the parasitic effect in a CMOS RF on chip integrated inductor, a concise method to increase the Q factor has been obtained when optimizing the layout parameter. Using this method, the Q factor of 7.9 can be achieved in a 5nH inductor (operating frequency is 2GHz) while the errors in inductance are less than 0.5% compared with the aimed values. It is proved by experiments that this method can guarantee the sufficient accuracy but require less computation time. Therefore, it is of great use for the design of the inductor in CMOS RF IC’s.
基金supported by the National Natural Science Foundation of China(Grant Nos.61234007,61404136,and 61504130)the Fund from the Ministry of Science and Technology of China(Grant No.2013YQ16055103)+1 种基金the Key Research&Development Program of Jiangsu Province,China(Grant No.BE2016007-2)the Major Project of Natural Science Research of the Higher Education Institutions of Jiangsu Province,China(Grant No.16KJA510006)
文摘In this paper, we present a three-dimensional（3D） vacuum packaging technique at a wafer level for a radio frequency micro-electromechanical system（RF MEMS） resonator, in which low-loss silicon vias is used to transmit RF signals.Au–Sn solder bonding is adopted to provide a vacuum encapsulation as well as electrical conductions. A RF model of the encapsulation cap is established to evaluate the parasitic effect of the packaging, which provides an effective design solution of 3D RF MEMS encapsulation. With the proposed packaging structure, the signal-to-background ratio（SBR） of 24 dB is achieved, as well as the quality factor（Q-factor） of the resonator increases from 8000 to 10400 after packaging.The packaged resonator has a linear frequency–temperature（ f –T） characteristic in a temperature range between 0℃ and 100℃. And the package shows favorable long-term stability of the Q-factor over 200 days, which indicates that the package has excellent hermeticity. Furthermore, the average shear strength is measured to be 43.58 MPa among 10 samples.
文摘An increase in the demand of broadband service has encouraged research and study to find a solution to offer an adequate amount of service. Living in this digital world with downloading video, voice or data leads us occasionally to have a shortage of bandwidth in the provided data. One of the solutions to cover the huge expected demand in the future is improving the communication systems by adding optical passive components to the Radio over Fiber (RoF) system. This work is mainly to increase the bandwidth that allows the small and single consumer at the last mile. We have shown that by adding the 40-GHz mm-wave to the system, Bit-Error-Rate (BER) has increased while Q-factor has decreased.
基金Supported by High Technology. Research and Development Program （No. 2004AA302042）, the Nanotechnology Program of Shanghai Science ＆ Technology Committee （No. 0352nm014）, the National Natural Science Foundation of China （No. 50275096）, Samsung Advanced Institute of Technology. （SALT）, Sansung Electronics Co., Ltd., and Shanghai-Applied Materials Research and Development Fund （No.0515）.
文摘Two micromachined solenoid-type inductors with different electroplated core structures, ellipse and rectangle, were fabricated, tested and compared in order to reach optimum designs for integrated induetoes and transformers. In the process of fabrication, UV-LIGA, dry. etching technique, fine polishing and eleetroplating techniques have been adopted to achieve high performance mieminduetor. Experimental results show that both types of the induetors are characterized by high inductance, Q-factor and low electrical resistance. While the inductance of the inductor with rectangular magnetic core is slightly higher than that with elliptical magnetic core, the quality factor of the latter is larger than that of the former.
文摘This paper describes a method for decomposing a signal into the sum of an oscillatory component and a transient component. The process uses the tunable Q-factor wavelet transform (TQWT): The oscillatory component is modeled as a signal that can be sparsely denoted by high Q-factor TQWT;similarly, the transient component is modeled as a piecewise smooth signal that can be sparsely denoted using low Q-factor TQWT. Since the low and high Q-factor TQWT has low coherence, the morphological component analysis (MCA) can effectively decompose the signal into oscillatory and transient components. The corresponding optimization problem of MCA is resolved by the split augmented Lagrangian shrinkage algorithm (SALSA). The applications of the proposed method to speech, electroencephalo-graph (EEG), and electrocardiograph (ECG) signals are included.
文摘This technical paper presents a fundamental approach for design and optimization of a spiral inductor using ASITIC(analysis and simulation of spiral inductors and transformers for ICs)and SpiralCalc(integrated spiral inductor calculator).Both tools are available for research and non-commercial purposes.Inductors are key components esp.for impedance matching and are designed such that they would exhibit a high Q-factor(quality-factor)for the specific inductance and frequency range of operation.A sample value of 5.3 nH is set for this paper for the spiral inductor design using the tools.For optimum Q-factor,an octagonal geometry for spiral inductor is used for ASITIC design,to have a close comparison to that of the SpiralCalc.Design methodologies for the optimization of the spiral inductor parameters such as the inductance and the Q-factor are discussed.Results comparison between the two tools is also presented.Design tradeoffs between inductor parameters are inevitable,and these parameters affect the performance of the inductor esp.at higher frequencies.With this,it is crucial that inductors be designed carefully for their effective frequency range of operation and specific requirements of the intended application.
文摘In the face of deteriorating environmental conditions in the world,water quality control is an urgent task.It can be solved by creating sensors with high accuracy and low cost,which requires the development of fundamentally new radiophysical methods that take advantage of the optical,microwave and millimeter wavelengths that have a significantly greater sensitivity to low concentrations of pollutants and a lower inertia.The article presents prototypes of measuring cells of the microwave and optical ranges as well as the results of an experimental study of water of various degrees of pollution with their help.The results show that the use of the highly sensitive method of capillary-waveguide resonance makes it possible to detect the presence of micro impurities in water with concentrations up to0.1%and to identify water even from sources of various natural origins.In addition,the use of measurements at several frequencies in the optical range will make it possible to solve the problem of creating water control sensors with high sensitivity to pollution and low cost.It can be concluded that the possibility of complex use of multiwave sensors(optical,infrared and microwave ranges)allows to increase the sensitivity and reliability of water quality assessment.
文摘New methods of an automated evaluation of the blood rheological parameters: 1) the viscosity, 2) electric conductivity and 3) the charge of erythrocytes have been theoretically and experimentally substantiated by way of registering the Q-factor of the tuned-circuit, containing a capillary with the blood flow. A design of an electronic measuring complex is based on modeling the physical blood conditions in the natural environment.
文摘Commercially available niobium (V) oxide [Nb2O5], with barium acetate [Ba(CH3COO)2] and magnesium acetate [Mg(CH3COO)2-4H2O] was used as the starting material in the sol-gel process for preparing Ba(Mg1/3Nb2/3)O3 (BMN) nanopowders. At first, Nb2O5 reacted with melting sodium hydroxide and transformed into dispersible oxide. The resulting glassy substance after cooling was dispersed and washed several times in distilled water to remove the Na+ ions. The as-prepared colloidal Nb2O5-nH2O was subsequently mixed with acetic solution of barium acetate and magnesium acetate according to the required molar proportions and followed by gelation. The ultrafine BMN powders were finally obtained after heat-treating the gel at 820℃for 1 h, and the as-sintered nanoceramics revealed a high relative density of 98.2%, and a high microwave Q-factor, of 10397 at 1.45GHz.
文摘Commercially available niobium (V) oxide [Nb_2O_5], with barium acetate[Ba(CH_3COO)_2] and magnesium acetate [Mg(CH_3COO)_2·4H_2O] was used as the starting material inthe sol-gel process for preparing Ba(Mg_(1/3)Nb_(2/3))O_3 (BMN) nanopowders. At first, Nb_2O_5reacted with melting sodium hydroxide and transformed into dispersible oxide. The resulting glassysubstance after cooling was dispersed and washed several times in distilled water to remove the Na^+ions. The as-prepared colloidal Nb_2O_5·nH_2O was subsequently mixed with acetic solution ofbarium acetate and magnesium acetate according to the required molar proportions and followed bygelation. The ultrafine BMN powders were finally obtained after heat-treating the gel at 820℃ for 1h, and the as-sintered nanoceramics revealed a high relative density of 98.2%, and a high microwaveQ-factor, of 10397 at 1,45GHz.
基金supported by the National Natural Science Foundation of China (Grant No. 51275384)the Key Project of National Natural Science Foundation of China (Grant No. 51035007)+1 种基金the Important National Science and Technology Specific Projects (Grant No. 2010ZX04014-016)the National Basic Research Program of China ("973" Program) (Grant No. 2009CB724405)
文摘Fault diagnosis of rotating machinery is of great importance to the high quality products and long-term safe operation.However,the useful weak features are usually corrupted by strong background noise,thus increasing the difficulty of the feature extraction.Thereby,a novel denoising method based on the tunable Q-factor wavelet transform(TQWT)using neighboring coefficients is proposed in this article.The emerging TQWT possesses excellent properties compared with the conventional constant-Q wavelet transforms,which can tune Q-factor according to the oscillatory behavior of the signal.Meanwhile,neighboring coefficients denoising is adopted to avoid the overkill of conventional term-by-term thresholding techniques.Because of having the combined advantages of the two methods,the presented denoising method is more practical and effective than other methods.The proposed method is applied to a simulated signal,a rolling element bearing with an outer race defect from antenna transmission chain and a gearbox fault detection case.The processing results demonstrate that the proposed method can successfully identify the fault features,showing that this method is more effective than the conventional wavelet thresholding denoising methods,term-by-term TQWT denoising schemes and spectral kurtosis.
基金This work was supported by funding from the Ministry of Education,Singapore(Grant Nos.MOE2016-T2-2-159,MOE2016-T2-1-128,MOE2015-T2-2-007,and MOE Tier 1 RG164/15)the National Research Foundation,Competitive Research Program(No.NRF-CRP18-2017-02)+1 种基金NSFC(No.61704082)A.D.acknowledges funding support from the Singapore Ministry of Education Academic Research Funds Tier 3 under Grant No.MOE2016-T3-1-006(S).
文摘Phonon polariton resonances in the mid-infrared spectral range demonstrate properties superior to noble metal-based plasmonics,owing to smaller dissipative loss and better field confinement.However,a conventional way to excite the localized phonon resonance involves ion etching,which reduces the attainable quality factors(Q-factors)of the resonators.We show that by introducing a deep subwavelength layer of dielectric gratings on a phononic substrate,localized dipolar resonance and higher order modes with high Q-factors 96 and 195,respectively,can be excited.We further demonstrate,via experiments and simulations,that the resonant wavelength and field confinement can be controlled by coupling the localized hybrid mode with propagating surface phonon-polaritons.We also observed for the first time the coupling between a localized dipolar mode and a propagating higher-order surface phonon-polariton mode.The results will be useful in designing on-chip,low-loss,and highly integrated phononic devices in the infrared spectral domain.
