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Lin W, Hu J, Zhao F, Sun S, Liu Y, Liu S, Yu F, Mak PU, Pun SH, Shum PP, Vai MI, Shao L. Adaptive Fiber-Ring Lasers Based on Isopropanol Filled Microfiber Coupler for High-Sensitivity Temperature Sensing. Micromachines (Basel) 2022; 13:1697. [PMID: 36296050 PMCID: PMC9610885 DOI: 10.3390/mi13101697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/04/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
We demonstrated a new method for temperature measurement inside a fiber ring laser (FRL) cavity. Different from traditional FRL temperature sensing system which need additional filter working as a sensor, a micro-fiber coupler (MFC) was designed as a beam splitter, filter, and temperature sensor. In addition, isopropanol, a liquid with very high photothermal coefficient, is selectively filled in the MFC in order to improve the sensitivity of the system on temperature. In the dynamic range of 20-40 °C, we obtained a good temperature sensitivity of -1.29 nm/°C, with linear fitting up to 0.998. Benefiting from the advantages of laser sensing, the acquired laser has a 3 - dB bandwidth of less than 0.2 nm and a signal-to-noise ratio (SNR) of up to 40 dB. The proposed sensor has a low cost and high sensitivity, which is expected to be used in biomedical health detection, real-time monitoring of ocean temperature, and other application scenarios.
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Affiliation(s)
- Weihao Lin
- State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau 999078, China
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Department of Electrical and Computer Engineering, University of Macau, Macau 999078, China
| | - Jie Hu
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Fang Zhao
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Siming Sun
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuhui Liu
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Shuaiqi Liu
- State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau 999078, China
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Department of Electrical and Computer Engineering, University of Macau, Macau 999078, China
| | - Feihong Yu
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Peng-Un Mak
- Department of Electrical and Computer Engineering, University of Macau, Macau 999078, China
| | - Sio-Hang Pun
- State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau 999078, China
| | - Perry-Ping Shum
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Mang-I Vai
- State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau 999078, China
- Department of Electrical and Computer Engineering, University of Macau, Macau 999078, China
| | - Liyang Shao
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- Peng Cheng Laboratory, Shenzhen 518005, China
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Wang J, Liu X, Yu Y, Li Y, Cheng C, Zhang S, Mak P, Vai M, Pun S. A Review on Analytical Modeling for Collapse Mode Capacitive Micromachined Ultrasonic Transducer of the Collapse Voltage and the Static Membrane Deflections. Micromachines (Basel) 2021; 12:mi12060714. [PMID: 34207176 PMCID: PMC8235715 DOI: 10.3390/mi12060714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/10/2021] [Accepted: 06/15/2021] [Indexed: 11/29/2022]
Abstract
Analytical modeling of capacitive micromachined ultrasonic transducer (CMUT) is one of the commonly used modeling methods and has the advantages of intuitive understanding of the physics of CMUTs and convergent when modeling of collapse mode CMUT. This review article summarizes analytical modeling of the collapse voltage and shows that the collapse voltage of a CMUT correlates with the effective gap height and the electrode area. There are analytical expressions for the collapse voltage. Modeling of the membrane deflections are characterized by governing equations from Timoshenko, von Kármán equations and the 2D plate equation, and solved by various methods such as Galerkin’s method and perturbation method. Analytical expressions from Timoshenko’s equation can be used for small deflections, while analytical expression from von Kármán equations can be used for both small and large deflections.
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Affiliation(s)
- JiuJiang Wang
- College of Computer Science and AI, Neijiang Normal University, Neijiang 641100, China; (J.W.); (Y.L.); (S.Z.)
- State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau 999078, China; (X.L.); (M.V.); (S.P.)
- Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau 999078, China
- BeiDou and Wisdom Medical Doctor Workstation, Neijiang Normal University, Neijiang 641100, China
| | - Xin Liu
- State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau 999078, China; (X.L.); (M.V.); (S.P.)
| | - YuanYu Yu
- College of Computer Science and AI, Neijiang Normal University, Neijiang 641100, China; (J.W.); (Y.L.); (S.Z.)
- State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau 999078, China; (X.L.); (M.V.); (S.P.)
- BeiDou and Wisdom Medical Doctor Workstation, Neijiang Normal University, Neijiang 641100, China
- Correspondence: (Y.Y.); (P.M.); Tel.: +86-832-234-3466 (Y.Y.); +853-8822-4393 (P.M.)
| | - Yao Li
- College of Computer Science and AI, Neijiang Normal University, Neijiang 641100, China; (J.W.); (Y.L.); (S.Z.)
| | - ChingHsiang Cheng
- School of Automotive Engineering, Wuhan University of Technology, Wuhan 430070, China;
| | - Shuang Zhang
- College of Computer Science and AI, Neijiang Normal University, Neijiang 641100, China; (J.W.); (Y.L.); (S.Z.)
- BeiDou and Wisdom Medical Doctor Workstation, Neijiang Normal University, Neijiang 641100, China
| | - PengUn Mak
- Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau 999078, China
- Correspondence: (Y.Y.); (P.M.); Tel.: +86-832-234-3466 (Y.Y.); +853-8822-4393 (P.M.)
| | - MangI Vai
- State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau 999078, China; (X.L.); (M.V.); (S.P.)
- Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - SioHang Pun
- State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macau 999078, China; (X.L.); (M.V.); (S.P.)
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Gao YM, Wu ZM, Pun SH, Mak PU, Vai MI, Du M. A Novel Field-Circuit FEM Modeling and Channel Gain Estimation for Galvanic Coupling Real IBC Measurements. Sensors (Basel) 2016; 16:E471. [PMID: 27049386 PMCID: PMC4850985 DOI: 10.3390/s16040471] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/28/2016] [Accepted: 03/29/2016] [Indexed: 11/16/2022]
Abstract
Existing research on human channel modeling of galvanic coupling intra-body communication (IBC) is primarily focused on the human body itself. Although galvanic coupling IBC is less disturbed by external influences during signal transmission, there are inevitable factors in real measurement scenarios such as the parasitic impedance of electrodes, impedance matching of the transceiver, etc. which might lead to deviations between the human model and the in vivo measurements. This paper proposes a field-circuit finite element method (FEM) model of galvanic coupling IBC in a real measurement environment to estimate the human channel gain. First an anisotropic concentric cylinder model of the electric field intra-body communication for human limbs was developed based on the galvanic method. Then the electric field model was combined with several impedance elements, which were equivalent in terms of parasitic impedance of the electrodes, input and output impedance of the transceiver, establishing a field-circuit FEM model. The results indicated that a circuit module equivalent to external factors can be added to the field-circuit model, which makes this model more complete, and the estimations based on the proposed field-circuit are in better agreement with the corresponding measurement results.
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Affiliation(s)
- Yue-Ming Gao
- College of Physics and Information Engineering, Fuzhou University, Fuzhou 350116, China; (Z.-M.W.); (M.D.)
- Key Lab of Medical Instrumentation & Pharmaceutical Technology of Fujian Province, Fuzhou 350116, China; (P.-U.M.); (M.-I.V.)
| | - Zhu-Mei Wu
- College of Physics and Information Engineering, Fuzhou University, Fuzhou 350116, China; (Z.-M.W.); (M.D.)
- Key Lab of Medical Instrumentation & Pharmaceutical Technology of Fujian Province, Fuzhou 350116, China; (P.-U.M.); (M.-I.V.)
| | - Sio-Hang Pun
- State Key Laboratory of Analog and Mixed Signal VLSI, University of Macau, Macau 999078, China;
| | - Peng-Un Mak
- Key Lab of Medical Instrumentation & Pharmaceutical Technology of Fujian Province, Fuzhou 350116, China; (P.-U.M.); (M.-I.V.)
- Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Mang-I Vai
- Key Lab of Medical Instrumentation & Pharmaceutical Technology of Fujian Province, Fuzhou 350116, China; (P.-U.M.); (M.-I.V.)
- State Key Laboratory of Analog and Mixed Signal VLSI, University of Macau, Macau 999078, China;
- Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau 999078, China
| | - Min Du
- College of Physics and Information Engineering, Fuzhou University, Fuzhou 350116, China; (Z.-M.W.); (M.D.)
- Key Lab of Medical Instrumentation & Pharmaceutical Technology of Fujian Province, Fuzhou 350116, China; (P.-U.M.); (M.-I.V.)
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Zhang TT, Mak PI, Vai MI, Mak PU, Law MK, Pun SH, Wan F, Martins RP. 15-nW Biopotential LPFs in 0.35- μm CMOS using subthreshold-source-follower Biquads with and without gain compensation. IEEE Trans Biomed Circuits Syst 2013; 7:690-702. [PMID: 24232630 DOI: 10.1109/tbcas.2013.2238233] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Most biopotential readout front-ends rely on the g m- C lowpass filter (LPF) for forefront signal conditioning. A small g m realizes a large time constant ( τ = C / g m) suitable for ultra-low-cutoff filtering, saving both power and area. Yet, the noise and linearity can be compromised, given that each g m cell can involve one or several noisy and nonlinear V- I conversions originated from the active devices. This paper proposes the subthreshold-source-follower (SSF) Biquad as a prospective alternative. It features: 1) a very small number of active devices reducing the noise and nonlinearity footsteps; 2) No explicit feedback in differential implementation, and 3) extension of filter order by cascading. This paper presents an in-depth treatment of SSF Biquad in the nW-power regime, analyzing its power and area tradeoffs with gain, linearity and noise. A gain-compensation (GC) scheme addressing the gain-loss problem of NMOS-based SSF Biquad due to the body effect is also proposed. Two 100-Hz 4th-order Butterworth LPFs using the SSF Biquads with and without GC were fabricated in 0.35- μm CMOS. Measurement results show that the non-GC (GC) LPF can achieve a DC gain of -3.7 dB (0 dB), an input-referred noise of 36 μV rms (29 μV rms ), a HD3@60 Hz of -55.2 dB ( - 60.7 dB) and a die size of 0.11 mm² (0.08 mm²). Both LPFs draw 15 nW at 3 V. The achieved figure-of-merits (FoMs) are favorably comparable with the state-of-the-art.
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Ieong CI, Mak PI, Lam CP, Dong C, Vai MI, Mak PU, Pun SH, Wan F, Martins RP. A 0.83- μW QRS detection processor using quadratic spline wavelet transform for wireless ECG acquisition in 0.35- μm CMOS. IEEE Trans Biomed Circuits Syst 2012; 6:586-595. [PMID: 23853259 DOI: 10.1109/tbcas.2012.2188798] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Healthcare electronics count on the effectiveness of the on-patient signal preprocessing unit to moderate the wireless data transfer for better power efficiency. In order to reduce the system power in long-time ECG acquisition, this work describes an on-patient QRS detection processor for arrhythmia monitoring. It extracts the concerned ECG part, i.e., the RR-interval between the QRS complex for evaluating the heart rate variability. The processor is structured by a scale-3 quadratic spline wavelet transform followed by a maxima modulus recognition stage. The former is implemented via a symmetric FIR filter, whereas the latter includes a number of feature extraction steps: zero-crossing detection, peak (zero-derivative) detection, threshold adjustment and two finite state machines for executing the decision rules. Fabricated in 0.35-μm CMOS the 300-Hz processor draws only 0.83 μW, which is favorably comparable with the prior arts. In the system tests, the input data is placed via an on-chip 10-bit SAR analog-to-digital converter, while the output data is emitted via an off-the-shelf wireless transmitter (TI CC2500) that is configurable by the processor for different data transmission modes: 1) QRS detection result, 2) raw ECG data or 3) both. Validated with all recordings from the MIT-BIH arrhythmia database, 99.31% sensitivity and 99.70% predictivity are achieved. Mode 1 with solely the result of QRS detection exhibits 6× reduction of system power over modes 2 and 3.
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Affiliation(s)
- Chio-In Ieong
- Department of Electrical and Computer Engineering, Faculty of Science and Technology,University of Macau, Taipa, Macao 999078, China.
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Abstract
In recent years, the increasing number of wearable devices on human has been witnessed as a trend. These devices can serve for many purposes: personal entertainment, communication, emergency mission, health care supervision, delivery, etc. Sharing information among the devices scattered across the human body requires a body area network (BAN) and body sensor network (BSN). However, implementation of the BAN/BSN with the conventional wireless technologies cannot give optimal result. It is mainly because the high requirements of light weight, miniature, energy efficiency, security, and less electromagnetic interference greatly limit the resources available for the communication modules. The newly developed intra-body communication (IBC) can alleviate most of the mentioned problems. This technique, which employs the human body as a communication channel, could be an innovative networking method for sensors and devices on the human body. In order to encourage the research and development of the IBC, the authors are favorable to lay a better and more formal theoretical foundation on IBC. They propose a multilayer mathematical model using volume conductor theory for galvanic coupling IBC on a human limb with consideration on the inhomogeneous properties of human tissue. By introducing and checking with quasi-static approximation criteria, Maxwell's equations are decoupled and capacitance effect is included to the governing equation for further improvement. Finally, the accuracy and potential of the model are examined from both in vitro and in vivo experimental results.
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Affiliation(s)
- Sio Hang Pun
- Department of Electrical and Electronics Engineering, Faculty of Science and Technology, University of Macau, Taipa, Macau, China.
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Pun SH, Gao YM, Mou PA, Mak PU, Vai MI, Du M. Multilayer limb quasi-static electromagnetic modeling with experiments for Galvanic coupling type IBC. Annu Int Conf IEEE Eng Med Biol Soc 2011; 2010:378-81. [PMID: 21097189 DOI: 10.1109/iembs.2010.5627992] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Intra-body communication (IBC) is a new, emerging, short-range and human body based communication methodology. It is a technique to network various devices on human body, by utilizing the conducting properties of human tissues. For currently fast developed Body area network(BAN)/Body sensor network(BSN), IBC is believed to have advantages in power consumption, electromagnetic radiation, interference from external electromagnetic noise, security, and restriction in spectrum resource. In this article, the authors propose an improved mathematical model, which includes both electrical properties and proportion of human tissues, for IBC on a human limb. By solving the mathematical model analytically on four-layer system (skin, fat, muscle, and bone) and conducting in-vivo experiment, a comparison has been conducted.
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Affiliation(s)
- S H Pun
- Department of Electrical and Electronics Engineering, Faculty of Science and Technology, University of Macau, Av. Padre Tomas Pereira, Taipa, Macau, China.
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Zhang TT, Mak PI, Vai MI, Mak PU, Wan F, Martins RP. An ultra-low-power filtering technique for biomedical applications. Annu Int Conf IEEE Eng Med Biol Soc 2011; 2011:1859-1862. [PMID: 22254692 DOI: 10.1109/iembs.2011.6090528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This paper describes an ultra-low-power filtering technique for biomedical applications designated as T-wave sensing in heart-activities detection systems. The topology is based on a source-follower-based Biquad operating in the sub-threshold region. With the intrinsic advantages of simplicity and high linearity of the source-follower, ultra-low-cutoff filtering can be achieved, simultaneously with ultra low power and good linearity. An 8(th)-order 2.4-Hz lowpass filter design example optimized in a 0.35-μm CMOS process was designed achieving over 85-dB dynamic range, 74-dB stopband attenuation and consuming only 0.36 nW at a 3-V supply.
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Affiliation(s)
- Tan-Tan Zhang
- Biomedical Engineering Laboratory, FST and State-Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao, China
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Gao YM, Pun SH, Du M, Mak PU, Vai MI. Simple electrical model and initial experiments for intra-body communications. Annu Int Conf IEEE Eng Med Biol Soc 2010; 2009:697-700. [PMID: 19963723 DOI: 10.1109/iembs.2009.5332704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Intra-Body Communication(IBC) is a short range "wireless" communication technique appeared in recent years. This technique relies on the conductive property of human tissue to transmit the electric signal among human body. This is beneficial for devices networking and sensors among human body, and especially suitable for wearable sensors, telemedicine system and home health care system as in general the data rates of physiologic parameters are low. In this article, galvanic coupling type IBC application on human limb was investigated in both its mathematical model and related experiments. The experimental results showed that the proposed mathematical model was capable in describing the galvanic coupling type IBC under low frequency. Additionally, the calculated result and experimental result also indicated that the electric signal induced by the transmitters of IBC can penetrate deep into human muscle and thus, provide an evident that IBC is capable of acting as networking technique for implantable devices.
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Affiliation(s)
- Y M Gao
- Key Laboratory of Medical Instrumentation & Pharmaceutical Technology, Fu jian Province, China
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Abstract
Intra-body communication (IBC) is a new, different "wireless" communication technique based on the human tissue. This short range "wireless" communication technology provides an alternative solution to wearable sensors, home health system, telemedicine and implanted devices. The development of the IBC enables the possibilities of providing less complexity and convenient communication methodologies for these devices. By regarding human tissue as communication channel, IBC making use of the conductivities properties of human tissue to send electrical signal from transmitter to receiver. In this paper, the authors proposed a new mathematical model for galvanic coupling type IBC based on a human limb. Starting from the electromagnetic theory, the authors treat human tissue as volume conductor, which is in analogous with the bioelectric phenomena analysis. In order to explain the mechanism of galvanic coupling type technique of IBC, applying the quasi-static approximation, the governing equation can be reduced to Laplace Equation. Finally, the analytical model is evaluated with on-body measurement for testing its performance. The comparison result shows that the developed mathematical model can provide good approximation for galvanic coupling type IBC on human limb under low operating frequencies.
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Affiliation(s)
- S H Pun
- Department of Electrical and Electronics Engineering, Faculty of Science and Technology, University of Macau, Av. Padre Tomás Pereira, Taipa, Macau
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