Time-domain Measurement Technique Research Articles

Phase-based motion estimation and SVR smooth for target-free 3D deformation measurement using stereophotogrammetry

Non-contact measurement methods based on computer vision have shown great potential for measuring structural surface displacement and strain due to their low cost and high efficiency. However, the traditional computer vision technology based on digital image correlation (DIC) is limited by its dependence on natural texture features of the surface and its susceptibility to environmental conditions, making it challenging to obtain effective and robust measurements of surface deformation. Additionally, these methods typically only focus on the structural response in the image plane, which makes it difficult to perform a comprehensive health assessment of complex structural components with asymmetry. Therefore, a time-domain visual measurement technique based on image phase information is proposed for measuring three-dimensional (3D) deformation of structures using stereophotogrammetry. The method involves extracting image phase information using 2D Gabor filters and applying it to dense optical flow estimation based on polynomial approximation and semi-global block matching (SGBM) for obtaining robust 3D displacement measurements. The support vector regression (SVR) is then used to perform hyperplane fitting of the original displacements for improving the smoothness of the 3D displacements. Finally, an intuitive strain conversion method is introduced to convert the 3D displacements into 3D strains. The performance of the proposed technique has been validated through numerical simulation experiments based on a physics-based graphics model (PBGM) in a synthetic environment. The robustness of the proposed method has been further proved through free attenuation vibration experiments on a steel ruler. The initial evaluation of the expected performance of the measurement plan has been enabled by performing a 1:1 reduction of the field measurement process in a synthetic environment. The results indicate that the proposed method is a promising method for accurately and reliably measuring structural deformation in both synthetic and real-world environments, especially for complex structural components with asymmetry.

Investigation of time domain measurement of electrochemical impedance spectrum in low frequency range for lithium-ion batteries using preset equivalent circuit model

A time domain measurement technique using a preset equivalent circuit model consisting of many series-connected resistor and capacitor parallel elements was examined as a measurement method of the electrochemical impedance spectrum of a lithium-ion battery excluding the apparent impedances from open circuit voltage change in the low frequency range. At first, a comprehensive experimental study was carried out to determine the standard condition of the applied signal suitable for this technique. It was established that an impedance spectrum from several tens of microhertz to several tens of millihertz can be accurately measured by selecting a proper, small rate and long duration constant current charge or discharge as the applied signal. Next, impedance spectra excluding the apparent impedances from open circuit voltage change were measured under various conditions using this technique, and basic characteristics of the impedances of the solid state diffusion processes of lithium that exist in the corresponding low frequency range were investigated. It was revealed that the impedance spectrum excluding the apparent impedances from open circuit voltage change in the low frequency range, from several tens of microhertz to several tens of millihertz, can be reasonably separated into two finite length Warburg impedances that can be clearly characterized by difference in their diffusion time constant values and in the state of charge dependence of their diffusion resistances. An Arrhenius type temperature dependence was confirmed for both of their diffusion resistances.

Effect of halide ions on the fluorescence properties of 3-aminoquinoline in aqueous medium.

Fluorescence (FL) quenching of 3-aminoquinoline (3AQ) by halide ions has been explored in an aqueous acidic medium using the steady-state and time-domain FL measurement techniques. The halide ions showed no significant change in the absorption spectra of 3AQ in an aqueous acidic medium. The FL intensity was strongly quenched by ions and the order of FL quenching by halide ions was . The decrease in FL lifetime along with the reduction in FL intensity of 3AQ suggested the dynamic nature of quenching. The obtained values were 328 for ions and 119 for ions and the values were ~ and , respectively. The observations suggested that the likely governing mechanism for FL quenching may be an electron transfer process and the involvement of the heavy atom effects.

Laser Doppler vibrometry-based characterization of bending waves by rotating viscoelastic panel materials applied in wallboard systems

A low-cost, thin-panel form of viscoelastic materials has found potential applications as constrained damping layers integrated into gypsum wallboards. The standardized chamber-based random-incident tests demonstrate drastically increased sound transmission losses without significantly increasing the board thickness and weight when the viscoelastic thin panels are integrated into gypsum wallboards in sandwich structure. For better understanding of their excellent effect as constrained damping layers, this work applies a laser Doppler vibrometer-based method in characterizing bending wave properties of the viscoelastic panel materials. The method involves a time-domain broadband measurement technique which correlates impulse responses taken at two points radially away from a bending wave source. Using reasonable sample sizes, boundary reflections will still obscure measurement results, particularly towards low frequencies. By rotating the panel under test, the coherence of direct wave pulses measured equidistant from the source and the lack thereof disturbing boundary reflections enables largely removing the undesirable reflections. In this way the direct wave pulses can be extracted by angular averaging and windowing in the time-domain. This paper discusses experimental investigations on the characterization method of bending wave properties using a laser Doppler vibrometer.

Orthogonal Code-Based Transmitted Radiation Pattern Measurement Method for 5G Massive MIMO Antenna Systems

This article presents a novel method to measure the transmitted radiation pattern by using orthogonal encoded signals during the process of hybrid analog-digital (HAD) beamformer development. One of the most important indicators in evaluating the performance of HAD beamforming systems is the measurement of the sub-array radiation patterns. However, as the number of elements increases, the number of combinations that can create sub-arrays increases significantly, and the conventional radiation pattern measurement process becomes exhaustive. However, when an orthogonal coded signal is used for the HAD beamforming system measurement, the magnitude and phase information of each element of the HAD beamforming system, including mutual coupling, can be simultaneously obtained from a single scan. Hence, it is possible to measure all feasible sub-array patterns very efficiently. Therefore, we propose an orthogonal code-based time-domain measurement technique and validate it with full-wave time-domain simulations. The results show that it is possible to receive element pattern information independently and that any sub-array pattern can be reconstructed with an accuracy greater than 99.99%.

Nanoscale heat transport through the hetero-interface of SrRuO3 thin films

A SrRuO3 thin film has been widely used as a metal electrode in electronic devices based on transition metal oxides, and hence it is important to understand its thermal transport properties to minimize a thermal degradation problem during the device operation. Using the time-domain thermoreflectance measurement technique, we investigate the cross-plane thermal conductivity of the SrRuO3 thin films with a thickness variation from 1 μm to 8 nm. We find that the thermal conductivity is reduced from about 6 W m−1 K−1 for the 1 μm thick film to about 1.2 W m−1 K−1 for the 8 nm thick film, and attribute this behavior to the boundary scattering of thermal carriers which originally have the mean free path of about 20 nm in a bulk state. Also, we observe a clear dip behavior of the thermal conductivity in the intermediate thickness around 30 nm which suggests an existence of a strong scattering source other than the film boundary. We explain this result by considering an additional interfacial scattering at the tetragonal-orthorhombic phase boundary which is formed during the strain relaxation with an increase of the film thickness.

Covalent-bonding-induced strong phonon scattering in the atomically thin WSe2 layer

In nano-device applications using two-dimensional (2D) van der Waals materials, a heat dissipation through nano-scale interfaces can be a critical issue for optimizing device performances. By using a time-domain thermoreflectance measurement technique, we examine a cross-plane thermal transport through mono-layered (n = 1) and bi-layered (n = 2) WSe2 flakes which are sandwiched by top metal layers of Al, Au, and Ti and the bottom Al2O3 substrate. In these nanoscale structures with hetero- and homo-junctions, we observe that the thermal boundary resistance (TBR) is significantly enhanced as the number of WSe2 layers increases. In particular, as the metal is changed from Al, to Au, and to Ti, we find an interesting trend of TBR depending on the WSe2 thickness; when referenced to TBR for a system without WSe2, TBR for n = 1 decreases, but that for n = 2 increases. This result clearly demonstrates that the stronger bonding for Ti leads to a better thermal conduction between the metal and the WSe2 layer, but in return gives rise to a large mismatch in the phonon density of states between the first and second WSe2 layers so that the WSe2-WSe2 interface becomes a major thermal resistance for n = 2. By using photoemission spectroscopy and optical second harmonic generation technique, we confirm that the metallization induces a change in the valence state of W-ions, and also recovers a non-centrosymmetry for the bi-layered WSe2.

Partial discharge measurement and analysis in high voltage IGBT modules under DC voltage

Insulation performance of high voltage IGBT modules is one of the key attributes in power system applications. However, the existing standards of IGBT devices and research on the evaluation of insulation performance of high voltage IGBT modules are insufficient; for example, partial discharge resistance under DC voltage blocking condition is not considered. In this paper, a new test was proposed to allow the measurement of partial discharges in all the components of IGBT modules under DC voltage. The topology of the measuring circuit is arranged in the polarity discrimination way to exclude the interference, and the voltage and discharge current waveforms during the partial discharge process are measured by the wideband time domain measurement technique. According to the proposed test, the discharge phenomenon of the IGBT modules below the rating voltage were detected. A comprehensive waveform analysis on the voltage and discharge current was performed, and the influence of the applied voltage on the waveform parameters was obtained. The waveform parameters are influenced by the applied voltage and insulation structure, which enables the discrimination of the causes of the observed partial discharge in the IGBT module under DC voltage by the waveform analysis technique. Based on the waveform analysis technique, the types and causes of the observed partial discharges were discussed and inferred, and the correctness of the inference was further verified by observation. The proposed test and waveform analysis technique provide the possibility to evaluate and distinguish partial discharges in the high voltage IGBT module under DC voltage, which may be helpful to insulation performance evaluation and insulation defect diagnosis in high voltage IGBT module.

Yield and Reliability of Nanocrystalline Graphene Field-Effect Gas Sensors

For the development of next-generation gas sensors with higher sensitivity, selectivity, responsivity and cost-effectiveness, carbon-based materials are a major research topic. Graphene, as a two-dimensional nanomaterial with a high surface-to-volume ratio and outstanding electronic properties, offers a good choice as a sensing layer [1]. However, for the successful application of reasonably priced graphene-based gas sensors a high fabrication yield and long-term stability are essential key requirements. Nevertheless, only few studies on the yield and reliability of graphene-based devices do exist [2]. Transfer-free nanocrystalline graphene field-effect transistors (ncGFETs), which are sensitive towards various toxic gases, including ammonia (NH3), nitrogen dioxide (NO2) and carbon monoxide (CO) can be fabricated by the use of our CMOS-compatible in situ catalytic chemical vapor deposition (CCVD) process. By this method we have fabricated hundreds of devices on oxidized two inch silicon wafers. In this contribution we report results on process yield and reliability, obtained from backgate input characteristics of 524 devices fabricated on a single two inch wafer. Electrical characterization has been performed using a Keithley SCS 4200 semiconductor parameter analyzer. The characterized ncGFETs exhibit nominal device widths of 20 µm and lengths of 3 µm and have been parameterized at a drain-to-source bias of VDS = -300 mV. The measurements reveal that 81.68 % of the fabricated ncGFETs show typical ambipolar behavior as is known from graphene devices (fig. 1). A field-effect (FE), defined via current on/off ratio, of at least 2 is observed for all of the devices within a backgate electric field strength range of ±2.4 MV/cm. Beyond that, in these devices larger field-effects are observed with 59.81 % exceeding a field-effect of 10 to 15 (10 ≤ FE < 15), 24.3% between 15 and 20 (15 ≤ FE < 20) and 7.25% larger than 20 (FE ≥ 20) (fig. 2). Due to the differences in the strength of the field-effect, material variations of our nanocrystalline graphene are expected. Moreover, by means of a statistical evaluation of the shift of the charge neutrality point the different doping levels of our devices are investigated. Furthermore, the ncGFETs show hysteresis effects that are enhanced by exposure to atmospheric environment and other gases, but are reduced in vacuum. Using the Pulsed Time-Domain Measurement (PTDM) technique [3] the surface charge trap density, which induces the hysteresis, is determined for various cases and its influence on the electrical and sensing characteristics of our device will be discussed. In addition, results on accelerated stress tests at high electrical fields and elevated temperatures will be presented as a first attempt to investigate the degradation and reliability of ncGFETs. [1] F. Schedin, A. K. Geim, S. V. Morozov, E. W. Hill, P. Blake, M. I. Katsnelson and K. S. Novoselov, Nat Mater, 6, 652 (2007). [2] A. D. Smith, S. Wagner, S. Kataria, B. G. Malm, M. C. Lemme and M. Ostling, Ieee T Electron Dev, 64, 3919 (2017). [3] R. S. Park, M. M. Shulaker, G. Hills, L. Suriyasena Liyanage, S. Lee, A. Tang, S. Mitra and H. S. Wong, ACS Nano, 10, 4599 (2016). Figure 1

Cancellation of interference for emission measurement in open area test site

This paper proposes a technique for implementing the concept of a virtual chamber for radiation emission measurements in time domain. At present measurements for electromagnetic emissions are carried out either with FFT based analyzers or with a conventional-hybrid spectrum analyzer based on heterodyning where interested band of frequencies is swept in the radio frequency range in an anechoic chamber. This method requires a large measurement time especially for wide band frequency measurements; therefore such methods cannot guarantee reliable results in open area. The difficulty lies in the interference cancellation from random sources for prolonged measurement duration.In this paper time domain measurement technique for electromagnetic emissions at open area test site has been proposed, designed, implemented and tested in a laboratory environment. The proposed technique captures multichannel signal from interference sources and equipment under test (EUT) simultaneously on different antenna ports. The continuous signal streams sampled at a very high rate before being fed to the stochastic gradient based adaptive filter. This materializes the cancelation of interference generated by various electronic sources using advanced digital processing techniques. The factors influencing the exactness in estimating interference are discussed in detail and cancelation of interference over the range of frequency (DC-1GHz) has been simulated. The simulation results exhibit how the proposed technique can revoke different kinds of interferences like continuous or transient, narrow or broad band. The performance evaluation of this method is verified through experiments conducted on real electronic appliances in open space environment and cross validated in an anechoic chamber up to 1GHz. The outcome of the research demonstrates the cancellation of both generated as well as naturally existing random interfering signals in an urban site polluted with electrical noise. The results substantiate the accuracy and usefulness of this new method for the measurement of radiation emissions and electromagnetic compatibility in accordance with CISPR standards. Pre-compliance electromagnetic compatibility testing is realized with this work without the need of an expensive anechoic chamber and with a reduced measurement time compared to the conventional measurement system.

NAC Measurement Technique on High Parallelism Probe Card with Protection Resistors

In this paper, a novel time-domain measurement technique on a high parallelism probe card with protection resistors installed is proposed. The measured signal amplitude decreases when the measurement is performed by Needle Auto Calibration (NAC) probing on a high parallelism probe card with installed resistors. Therefore, the original signals must be carefully reconstructed, and the compensation coefficient, which is related to the number of channel branches and the value of protection resistors, must be introduced. The accuracy of the reconstructed signals is analyzed based on the varying number of channel branches and various protection resistances. The results demonstrate that the proposed technique is appropriate for evaluating the overall signal performance of probe cards with Automatic Test Equipment (ATE), which enhances the efficiency of probe card performance test dramatically.

Free-Space Time Domain Position Insensitive Technique for Simultaneous Measurement of Complex Permittivity and Thickness of Lossy Dielectric Samples

A novel time domain measurement technique is proposed to facilitate the simultaneous measurement of electrical properties (complex relative permittivity) and geometrical parameters (thickness) of the material under test (MUT). The overall process is noninvasive and noncontacting, which uses the measured scattering data of the MUT in the equivalent time domain or spatial domain. The effective time domain scattering data are employed to detect the primary and secondary peaks of the overall reflection and transmission coefficients. To this end, a novel algorithm is proposed to obtain the complex permittivity and thickness of the MUT in terms of extracted reflection and transmission power peaks. From the practical point of view, the main advantage of the proposed scheme is that one avoids the complicated calibration procedure normally required to define the reference plane. For increasing the accuracy of the overall reconstruction process, an automated optimization procedure based on parameter sensitivity analysis is proposed, which uses standard time gating procedure to implement the corresponding direct problem. The proposed technique is validated by extracting the relative permittivity, the dielectric loss (effective conductivity), and the thickness of various standard materials, such as polyethylene, Plexiglas, PVC, mortar, nylon, and so on, and comparing the extracted data with their values available in the literature.

Quantitative Analysis of Time-Domain Supported Electrochemical Impedance Spectroscopy Data of Li-Ion Batteries: Reliable Activation Energy Determination at Low Frequencies

Physico-chemical processes in batteries are taking place on a broad time scale from fractions of seconds to the order of days [1]. Thus, for an accurate characterization of transport and mobility processes in batteries using electrochemical impedance spectroscopy (EIS), a large frequency range of up to ten decades must be covered. This implies measurement durations on the order of days for low frequency measurements, yielding the risk of distorting electrochemical instabilities in the battery and a considerable change of its state of charge (SOC) due to the probing ac current excitation. It is shown that the SOC change is frequency dependent and with 10-15% of the nominal battery capacity for the sub-millihertz range hardly a small perturbation. Nevertheless, these obstacles can be mitigated by the time domain measurement (TDM) technique [2-4]. TDM is limited to impedance measurements at low frequencies, with a small and frequency-independent SOC change. The combination of TDM and EIS, called time-domain supported electrochemical impedance spectroscopy (TD-EIS), opens up the possibility for a time-efficient implementation of impedance spectroscopy over a large frequency range down to microhertz frequencies [5]. In this work, TD-EIS at varying temperatures in combination with data fitting using an electrical equivalent circuit battery model, is used for the high-accuracy quantification of low-frequency mobility parameters in lithium-ion batteries. It is experimentally demonstrated, for the first time, that the phase of the impedance measurements converges in the sub-millihertz range, which permits a reliable quantification of diffusion kinetics. Moreover, it is shown that with TD-EIS time savings of up to 80% compared to the standard EIS measurement are feasible. From the electrical equivalent circuit battery model fit, an accurate estimate of charge transfer resistance and, in particular, also solid-state diffusion rate are obtained. Both processes follow an Arrhenius law, allowing the determination of activation energies with small variance. The results for the charge transfer process and for the solid-state diffusion process are within the range of literature values measured for similar systems. This work has been published in JECS [6].

Chipless RFID tags and sensors: a review on time-domain techniques

In the past few years Radio Frequency Identification(RFID)has grown to be one of the most popular technologies in the area of identification systems. Following a brief survey of RFID systems, this paper provides a technical review of work undertaken in the field of time-domain chipless RFID tags and sensors. This paper aims not only to address the chipless tags which use Time Domain Reflectometry (TDR) concept for data encoding but also for the use of Ultra-Wideband Impulse-Radar (UWB-IR) as a time-domain measurement technique. The penultimate section intends to focus on time-domain reading setups and finally, a brief comparison between this method and other chipless techniques is provided.

Qualification of ECM-Processes by Electro Impedance Spectroscopy

Electrochemical machining (ECM) is an appropriate technology for structuring a wide range of metals and alloys independent of their mechanical properties. Further advantages the occurence of no tool wear and almost no change in the material properties of the work piece material due to the machining. As different studies showed it is possible to manufacture structures in the µm-range and also in the sub µm-range. The resulting geometry and feature size depend on the electrolyte, the working gap, the electric field, the flow conditions within the working gap and the material structure. The working gap is the most important parameter regarding the critical dimensions of ECM. Actual high resolution processes are limited by the process time due low current densities, while faster processes are limited by the resolution due to the dimensions of the double layer and the need for purging.\\Regarding these limits an enhanced understanding of the electrochemical processes within the working gap is mandatory for the optimization of the ECM. Therefore a measurement device is realised utilising electrochemical impedance spectroscopy (EIS), which is one technique to obtain a wide set of thermodynamic and kinetic parameters related to the electrochemical processes like reactions, adsorption, desorption and diffusion in the gap. There the impedance, which is the complex ratio between the voltage and the current in an AC circuit, is measured as a function of the frequency and it is compared to an equivalent circuit, composed out of basic elements representing the chemical sub processes. The spectrometer is realized by combining a commercial potentiostat with computer based signal processing realized in MATLAB\copyright. The spectrometer implements time-domain measurement techniques (Fourier transformation) for a strong reduction of measurement time. This time reduction allows in situ measurements.\\The presented spectrometer enables characterization of standard material systems like cooper, as well as the identification of the time-critical chemical processes and steps in more complex systems.

UWB 안테나 링크 특성화를 위한 네트워크 분석기를 이용한 시간영역 측정 및 분석기술 연구

본 논문에서는 임펄스 신호를 방사하는 UWB 안테나의 링크 특성을 분석하기 위해 주파수영역에서 안테나 특성을 측정하기 위해 사용하는 네트워크 분석기를 이용한 시간영역 측정 및 분석기술에 대해 연구하였다. 이를 위해 네트워크 분석기에서 획득한 데이터를 줌-인(Zoom-In)이 가능한 시간영역으로 변환하기 위한 CZT(Chirp z-Transform) 알고리즘을 개발하였다. 개발된 CZT 알고리즘을 이용하여 주파수영역에서 각 안테나 링크에 대한 파형분석을 통해 표준이산푸리에 변환(Discrete Fourier Transform)보다 고속으로 변환이 가능하고 임의의 원하는 구간을 줌-인 함으로서 효율적으로 파형분석이 가능함을 증명하였다.

Transient Frequency-Domain Thermal Measurements With Applications to Electronic Packaging

Non-uniform power distribution, increased die-size, and multiple-chip modules present new challenges for the thermal management of modern integrated circuit (IC) packages. Thermal characterization techniques capable of resolving partial thermal resistances at the component level have received increased emphasis in development of advanced packaging technologies. This paper aims to develop a practical method for thermal characterization of IC packages using the frequency-domain measurement technique as a complementary technique to the widely used time-domain thermal transient measurement technique. This paper discusses practical implementation of the technique and demonstrates both thermal modeling and experimental results. Thermal impedances measured in frequency-domain yield the structure function, which describes the dynamic thermal response of the device based on thermal RC network analysis. Various applications of this technique in thermal characterization of the IC packages subjected to field conditions are also discussed.

An Attempt of Fan Beam Microwave CT System which Determines the Straight Transmission Path by Time Domain Measurement of Demodulated DC Voltage

We have developed demodulated direct current voltage-based microwave CT (DC-MCT) which is composed on the basis of chirp-pulse microwave CT. DC-MCT was used time domain measurement technique to determine the shortest propagation path between the transmitting-and receiving-antennas. By using standard signal generator with the low phase noise and phase synchronization of signal source, the reconstructed amplitude-and phase-images can be obtained. A study of high speed imaging, the method of measurement and the influence of overshoot characteristics from the low pass filter were examined, then these images were evaluated for the number of rotary scanning of 50 and 72. In addition, for the purpose of improvement of resolution, pursuing a time domain spectrum which gives the max value of amplitude was showed the possibility to improve receiver dynamic range. At the result, this paper shows usefulness of new method for microwave imaging.

Electromagnetic properties of the ground: Part II – The properties of two selected fine-grained soils

In Part I of this paper it was established that electromagnetic signal velocities, for instance as used in ground penetrating radar use, are related to the geotechnical properties of Liquid Limit, dry density and percentage linear shrinkage. It was thus established that such geophysical techniques potentially provide an insight into the geotechnical properties of fine-grained soils, as well as illustrating the equal potential of informing radar survey planning and data interpretation through prediction of soil geophysical properties from geotechnical data. In order to extend that research, the work described herein aimed to consider how signal velocities relate to the wide variations in water contents that may occur for a soil in the field, from oven dry to more than 90% by volume. Through the use of time-domain and frequency-domain measurement techniques, data were obtained that allow consideration of soil effects on commercial water content measurement systems and radar equipment. Potentially the most important outcome is that the data indicate that the three geotechnical states (friable, plastic and liquid) give rise to three different signal velocity/water content relationships. In the friable state, the relationship shows large increases in apparent permittivity (as a proxy for signal velocity) with water content, together with increasing electromagnetic dispersion (i.e. variations in velocity with frequency). In the more common plastic state, often not fully considered in the literature, apparent permittivity is shown to increase almost linearly with water content at high frequencies, but in fact can decrease at lower frequencies. This anomaly is explained by the reduction in electromagnetic dispersion caused by reducing dry density. For the liquid state, the relationships are shown to be similar to the plastic state, but with a step increase in apparent permittivity potentially related to soil pore sizes exceeding a critical limit. It is also shown that the plastic and liquid state linear relationships are related to similar trends in the apparent permittivity of the water phase. It is concluded that, when considered over very wide water content and signal frequency ranges, the electromagnetic properties of soils are complex but can be related to geotechnical states and properties. It is, therefore, proposed that the research detailed herein provides a useful initial step in the creation of an electromagnetic properties database of relevance to underground space development.

Parameter extraction from BVD electrical model of PZT actuator of micropumps using time-domain measurement technique

To minimize the power consumption of the piezoelectric micropumps utilized in the microfluidics field, suitable models are required to enable the optimization of the lead zirconate titanate (PZT) actuator driving circuits. The recent research shows that the electromechanical parameters of piezoelectric materials can be obtained from Butterworth Van-Dyke (BVD) model. The current study presents a novel time-domain measurement technique for extracting the parameters of a BVD electrical model describing a PZT actuator of the micropump excited by a square pulse with a relatively high voltage and low frequency. The validity of the BVD model is evaluated by using MATLAB software to solve the ordinary differential equations of the electrical model and then comparing the numerical results obtained for the current response of the PZT actuator with the experimentally-observed results. The BVD model has been found to be valid for this specific application of piezo actuators. A good agreement is observed between the two sets of result, and thus the validity of the BVD model and the proposed time-domain measurement technique is confirmed.