• Smart Structures and Systems
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• 제22권4호
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• pp.369-382
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• 2018

Novel design of interdigitated electrodes capable of increasing the performance of piezoelectric transducers are proposed. The new electrodes' geometry improve the electromechanical coupling by offering an enhanced adaptation of the electric field to the interdigitated electrode configuration. The proposed analysis is based on finite element modeling and takes into account local polarization effect. It is shown that the proposed electrodes considerably increase the strain generation compared to flat electrode arrangement used for Macro Fiber Composite (MFC) and Active Fiber Composite (AFC) actuators. Also, electric field singularities are reduced allowing better reliability of the transducer against electric failure.

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2781-2786
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• 2013

We examined the effect of electrode fingers and gaps of coplanar interdigitated electrode (IDE) structures to characterize the ammonium salt-containing polyelectrolyte film of resistance-based humidity sensors. IDEs designed for this purpose were flexible gold electrodes deposited on a polyimide substrate using a printing process because the geometry presents a potential for tunable sensitivity over other electrode designs. The basic design of the sensors consisted of IDEs with a different number of electrode fingers such as 3, 4, and 5 and gap sizes of 310, 360, 410, and $460{\mu}m$. Details of the AC complex impedance characteristics such as the Nyquist plot, Bode plot, and activation energy based on electrode construction were investigated.

• 한국세라믹학회지
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• 제41권3호
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• pp.216-220
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• 2004

본 논문은 압전세라믹의 압전상수 d$_{33}$ 를 이용한 적층 세라믹 박판 작동층 IDEAL (InterDigitated Electrode Actuation Layer)의 개발에 관한 것이다. 대부분의 박판 압전 작동층은 압전상수 d$_{31}$ 효과를 이용하고 있다. 현재 개발된 압전작동기의 성능을 향상시키기 위해 많은 연구가 수행 중에 있으며, 그 중 한 방법이 압전상수 d$_{33}$ 를 이용하는 방법이다. 압전세라믹의 압전상수 d$_{33}$ 는 압전상수 d$_{31}$ 보다 일반적으로 두배 정도이기 때문에 d$_{33}$ 작동 효과를 활용하면 작동기의 성능을 향상시킬 수 있다. 미국 MIT에서 개발된 AFC와 NASA Langley 연구소 연구팀이 개발한 LaRC-MFC$^{TM}$는 d$_{33}$ 작동 효과를 활용하였으나 빗살형 전극이 작동층 상하 표면에 부착되어 있어 완전한 d$_{33}$ 작동 효과를 활용하였다고 볼 수 없다. 본 논문에서는 빗살형 전극을 세라믹 층간에 삽입한 적층형 세라믹 박판 작동층을 설계하고 제작하였다. 제작된 작동층의 작동 스트레인을 측정하였고 LaRC-MFC$^{TM}$의 작동 스트레인과 비교한 결과, 본 연구에서 개발한 박판 세라믹 작동층이 15% 이상의 작동 스트레인을 발생시킬 수 있음을 확인하였다.

• International Journal of CAD/CAM
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• 제12권1호
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• pp.20-28
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• 2012

Finite Element Analysis (FEA) is often used to identify local stress/strain concentrations where a component is likely to fail. In order to reduce the degree of strain concentration, component thickness can be increased in those regions, or a stronger material can be used. In short fiber reinforced composite materials, strength and stiffness can be increased through proper fiber alignment. The field-aided microtailoring (FAiMTa) process is one promising method for doing this. FAiMTa uses principles of dielectrophoresis to preferentially align particles or fibers within a matrix. To achieve the preferred fiber orientation, an interdigitated electrode network must be integrated into the mold halves which can be fabricated by additive manufacturing (AM) processes. However, the process of determining the preferred fiber arrangements and electrode locations can be very challenging. This paper presents algorithms to semi-automate the interdigitated electrode design process. The algorithm has been implemented in the Solidworks CAD system and is demonstrated in this paper.

• 분석과학
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• 제28권1호
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• pp.8-16
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• 2015

We prepared a novel electrochemical gas sensor (EG sensor) based on interdigitated electrode (IDE) coated with vinyl ionic liquids (ILs) as electrolyte and Pt-Ru-Mo/MWNT electrocatalysts for occurring redox-active of CNCl gas. The vinyl ILs such as 1-butyl-3-(vinylbenzyl)imidazolium chloride, $[BVBI]^+Cl^-$, and 3-hexyl-1-vinylimidazolium bromide, $[HVI]^+Br^-$, were synthesized by $SN_2$ reaction in order to use electrolyte. The Pt-Ru-Mo/MWNT electrocatalysts were also prepared by one-step radiation-induced reduction of metal ions in the presence of MWNTs as supports. The fabricated EG sensor with vinyl ILs electrolyte was evaluated through optical microscopy (OM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The prepared EG sensor is clearly detected over 2.0 ppm CNCl gas and is exhibited a liner relationship between current and concentration over a region of 10-100 ppm.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.407-410
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• 2006

Selection of flow channel in the separation plate of PEMFC is very important parameter to improve its performance and reduce parasite loss. Flow patterns in the channel have great influence on the transport of hydrogen and all and water generated from electrochemical reaction in diffusion layer In this study, fluid flow in flow channel with parallel and interdigitated patterns are simulated three dimensionally on full flow domain including anode and cathode electrode together. The numerical results show that the fuel cell with interdigitated flow channel represents better performance than that with parallel flow channel due to its strong convective transport across the gas diffusion layer. But the pressure drop in parallel flow channel is much more than that in nterdigitated flow channel. The effect of temperature and stoichiometric number on performance can be calculated and analyzed as well.

• Food Science and Biotechnology
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• 제18권1호
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• pp.89-94
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• 2009

Frequent outbreaks of foodborne illness have been increasing the awareness of food safety. Conventional methods for pathogen detection and identification are labor-intensive and take days to complete. Some immunological, rapid assays are developed, but these assays still require prolonged enrichment steps. Recently developed biosensors have shown potential for the rapid detection of foodborne pathogens. In this study, an impedimetric biosensor was developed for rapid detection of Salmonella entritidis in food sample. To develop the biosensor, an interdigitated microelectrode (IME) was fabricated by using a semiconductor fabrication process. Anti-Salmonella antibodies were immobilized based on neutravidin-biotin binding on the surface of the IME to form an active sensing layer. To evaluate the effect of electrode gap on sensitivity of the sensor, 3 types of sensors with different electrode gap sizes (2, 5, and $10{\mu}m$) were fabricated and tested. The impedimetric biosensor could detect $10^3\;CFU/mL$ of Salmonella in pork meat extract with an incubation time of 5 min. This method may provide a simple, rapid, and sensitive method to detect foodborne pathogens.

• 전기학회논문지
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• 제62권7호
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• pp.974-979
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• 2013

$TiO_2$ thin films are fabricated using R.F.sputtering method. $TiO_2$ thin films are coated on $Al_2O_3$ substrate printed IDE(interdigitated electrode). Impedance of thin films decreases according to increase relative humidity and it increases according to decrease measuring frequency. When substrate temperature is room temperature, impedance of thin films is from 45.68[MHz] to 37.76[MHz] within the limits from 30[%RH] to 75[%RH] at 1[kHz]. Whereas when substrate temperature is 100[$^{\circ}C$], impedance of thin films is from 692[kHz] to 539[kHz] within the limits from 30[%RH] to 75[%RH] at 1[kHz]. Impedance variation of thin films is bigger in low frequency regions than in high frequency regions. When substrate temperature is 100[$^{\circ}C$], impedance of thin films is lower than that of room temperature.

• 센서학회지
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• 제23권1호
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• pp.42-45
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• 2014

Recently, tremendous application utilizing electrospun nanofibers have been actively reported due to its several advantages, such as high surface to volume ratio, simple fabrication and high-throughput manufacturing. In this paper, we developed highly sensitive and consistent nanofiber humidity sensor by electrospinning. The humidity sensor was fabricated by rapid electrospinning (~2 sec) $TiO_2$/PVP/LiCl mixed solution on the micro-interdigitated electrode. In order to evaluate the humidity sensing performances, we measured current response using DC bias voltage under various relative humidity levels. The results show fast response / recovery time and marginal hysteresis as well as long-term stability. In addition, with the aid of micro-interdigitated electrode, we can reduce a total resistance of the sensor and increase the total reaction area of nanofibers across the electrodes resulting in high sensitivity and enhanced current level. Therefore, we expect that the electrospun nanofiber array for humidity sensor can be feasible and promising for diverse humidity sensing application.

• JSTS:Journal of Semiconductor Technology and Science
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• 제5권1호
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• pp.30-37
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• 2005

We present an air bridge type electrode system with tunable electrode distance for detecting electroactive biomolecules. It is known that the narrower gap between electrode fingers, the higher sensitivity in IDA (interdigitated array) electrode. In previous researches on IDA electrode, narrower patterning required much precise and expensive equipment as the gap goes down to nanometer scale. In this paper, an improved method is suggested to replace nano gap pattering with downsizing electrode distance and showed that the patterning can be replaced by thickness control using metal deposition methods, such as electroplating or metal sputtering. The air bridge type electrode was completed by the following procedures: gold patterning for lower electrode, copper electroplating, gold deposition for upper electrode, photoresist patterning for gold film support, and copper etching for space formation. The thickness of copper electroplating is the distance between upper and lower electrodes. Because the growth rate of electroplating is $0.5{\mu}m\;min^{-1}$, the distance is tunable up to hundreds of nanometers. Completed electrodes on the same wafer had $5{\mu}m$ electrode distance. The gaps between fingers are 10, 20, 30, and $40{\mu}m$ and the widths of fingers are 10, 20, 30, 40, and $50{\mu}m$. The air bridge type electrode system showed better sensitivity than planar electrode.