• ETRI Journal
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• 제46권3호
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• pp.413-420
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• 2024

A dual-band bio-implantable compact antenna with a meander-line structure is presented. The proposed meander-line antenna resonates at the industrial, scientific, and medical (2.4 GHz) and wireless medical telemetry (1.4 GHz) bands. The meander-line structure is selected as a radiating patch given its versatile and effective design. With a dimension of only 10 mm × 10 mm × 0.635 mm, the designed antenna is compact. Considering a skin phantom, the proposed antenna was designed, optimized, and simulated. The Rogers RT/duroid 6010 substrate material with high dielectric constant was used to fabricate the meander-line dual-band implantable antenna, which was validated experimentally. The superstrate was made of the same material. Experiments were conducted on skin-mimicking gel. The designed meander-line antenna has a high peak gain of -21 dBi at 2.4 GHz, and its maximum specific absorption rate is compliant with IEEE safety standards.

• 한국전기전자재료학회논문지
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• 제26권3호
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• pp.171-176
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• 2013

In this paper, we present a MEMS (micro-electro-mechanical system) implantable blood pressure sensor which has designed and fabricated with consideration of size, design flexibility, and wireless detection. Mechanical and electrical characterizations of the sensor were obtained by mathematical analysis and computer aided simulation. The sensor is composed of two coils and a air gap capacitor formed by separation of the coils. Therefore, the sensor produces its resonant frequency which is changed by external pressure variation. This frequency movement is detected by inductive coupling between the sensor and an external antenna coil. Theoretically analyzed resonant frequency of the sensor under 760 mmHg was calculated to 269.556 MHz. Fused silica was selected as sensor material with consideration of chemical and electrical reaction of human body to the material. $2mm{\times}5mm{\times}0.5mm$ pressure sensors fitted to radial artery were fabricated on the substrates by consecutive microfabrication processes: sputtering, etching, photolithography, direct bonding and laser welding. Resonant frequencies of the fabricated sensors were in the range of 269~284 MHz under 760 mmHg pressure.

• 센서학회지
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• 제14권5호
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• pp.322-330
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• 2005

A new type of transducer, piezoelectric floating mass transducer (PFMT) which has advantages of piezoelectric and electromagnetic transducer has been proposed and implemented for the implantable middle ear hearing devices. By the uneven bonding of piezoelectric material to the inner bottom of transducer case, the PFMT can vibrate back-and-forth along the longitudinal axis of the transducer even though the piezoelectric material within the cylindrical case produces only the bilateral expansion and contraction according to the applied electrical signal. To improve efficiency of the PFMT, the multi-layered piezoelectric material has been adapted. The small number of components in the PFMT enables the simple manufacturing and the easy implanting into the middle ear. In order to examine the characteristics of vibration, mechanical modeling and finite element analyses of the proposed transducer have been performed. From the result of theoretical analyses and the measured data from the experiment, it is verified that the implemented PFMT can be used in implantable middle ear hearing devices.

• Transactions on Electrical and Electronic Materials
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• 제18권6호
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• pp.359-363
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• 2017

A slotted implantable patch antenna with microstrip feeding is proposed for industrial, scientific, and medical band applications. The result is verified by implanting the antenna in animal tissue. Further, by varying the ground width and introducing a defect into the ground structure, the antenna becomes applicable for worldwide interoperability for microwave access operations. A simulation is performed using Empire XCcel software. An Agilent vector network analyzer is used for analyzing the return loss performance. Simulated and measured results are compared. Antennas with and without defected ground structure both have key advantages including low profile, desirable return loss, good impedance matching and required bandwidth.

• Journal of Chest Surgery
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• 제40권10호
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• pp.691-695
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• 2007

배경: 중심정맥 도관은 1979년 처음 사용된 이래로 암환자의 치료에 있어 많은 편의를 제공하였다. 이에 본원 흉부외과에서는 완전 거치형 정맥도관의 임상 양상 및 사용에 따른 합병증 등을 분석하여 향후 치료에 도움이 되고자 본 연구를 하였다. 대상 및 방법: 2004년 11월부터 2006년 2월까지 완전 거치형 정맥도관 시술을 받은 100명의 환자를 대상으로 후향적 연구를 하여 다음과 같은 결과를 얻었다. 결과: 완전 거치형 정맥 도관 시술의 삽입정맥으로는 우측 쇄골하정맥 삽입이 74예(74%)였으며 좌측쇄골하 정맥(21예, 21%), 우측 경정맥(3예, 3%), 좌측 경정맥(1예, 1%)을 사용하였으며 1예에서는 우측 대퇴정맥을 사용하였다. 초기 합병증으로는 위치 이상이 5예(5%)와 동맥천자한 경우 5예 있었다. 만기 합병증으로는 쇄골하 정맥 혈전 형성이 한 예 있어 현재 항응고제 복용중이며 pinch off 증후군이 2예 있었다. 그 외의 초기 또는 만기 합병증은 없었다. 결론: 완전 거치형 도관의 사용은 합병증의 발생률은 낮고 비교적 안전한 방법이지만 감염, 혈전 형성, 도관의 절단 등은 장기간 사용시 나타날 수 있는 합병증으로 초기에 진단 및 치료가 된다면 더 큰 합병증을 예방할 수 있다.

• Transactions on Electrical and Electronic Materials
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• 제15권2호
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• pp.55-59
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• 2014

An implantable CPW fed monopole antenna embedded into human tissue is proposed for ISM band biomedical applications. The proposed antenna is made compatible for implantation by embedding it in an alumina ceramic substrate (${\Box}_r=9.8$ and thickness=0.65 mm). The proposed antenna covers the ISM band of 2.45 GHz. The radiation parameters, such as return loss, E-Plane, H-Plane, are measured and analyzed, using the method of moments. The proposed antenna has substantial merits over other implanted antennas, like low profile, miniaturization, lower return loss, and better impedance matching and high gain.

• Transactions on Electrical and Electronic Materials
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• 제16권5호
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• pp.250-253
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• 2015

A novel implantable CPW fed Apollian shaped antenna embedded into human tissue is proposed for ISM band biomedical applications. The proposed antenna is made compatible for implantation by embedding it in an alumina ceramic substrate(ε_r=9.8 and thickness= 0.65 mm). The proposed antenna covers the ISM band of 2.45 GHz. The radiation parameters such as return loss, xy-plane, xz-plane, and yz-plane etc., are measured and analyzed using the agilent vector network analyzer. The proposed antenna has substantial advantages, including low profile, miniaturization ability, lower return loss, better impedance matching, and high gain over conventional implanted antennas.

• 한국전기전자재료학회논문지
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• 제25권6호
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• pp.445-450
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• 2012

We have developed an implantable wireless sensor for real time pressure monitoring of blood circulation system. MEMS (micro-electro-mechanical system) technology was adopted as a sensor development method. The sensor is composed of photolithographically patterned inductors and a distributed capacitor in gap between the inductors. A resulting LC resonant system produces its resonant frequency in range of 269 to 284 MHz at 740 mmHg. To read the resonant frequency changed by blood pressure variation, we developed a custom readout system based on a network analyzer functionality. The bench-top testing of the pressure sensors showed good mechanical and electrical functionality. A sensor was implanted into tibial artery of farm pig, and interrogated wirelessly with accurate readings of blood pressure. After 45 days, the sensor's electrical response and histopathology were studied with good frequency reading and biocompatibility.

• 한국전기전자재료학회논문지
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• 제34권6호
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• pp.487-494
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• 2021

Piezoelectric generators use direct piezoelectric effects that convert mechanical energy into electrical energy. Many studies were attempted to fabricate piezoelectric generators using piezoelectrics such as ZnO, PZT, PVDF. However, these various inorganic/organic piezoelectric materials are not suitable for bio-implantable devices due to problems such as brittleness, toxicity, bio-incompatibility, bio-degradation. Thus, in this paper, piezoelectric generators were prepared using a silk fibroin film which is bio-compatible by dip-coating method. The silk fibroin films are a mixed state of silk I and silk II having stable β-sheet type structures and shows the d₃₃ value of 8~10 pC/N. There was a difference in output voltages according to the thickness. The silk fibroin generators, coated 10 times and 20 times, revealed the power density of 16.07 μW/cm² and 35.31 μW/cm² using pushing tester, respectively. The silk fibroin generators are sensitive to various pressure levels, which may arise from body motions such as finger tapping, foot pressing, wrist shaking, etc. The silk fibroin piezoelectric generators with bio-compatibility shows the applicability as a low-power implantable piezoelectric generator, healthcare monitoring service, and biotherapy devices.

• 한국전기전자재료학회논문지
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• 제30권7호
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• pp.407-412
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• 2017

This paper introduces a biocompatible packaging system for implantable medical device having a hermetic sealing, such that a perfect physical and chemical isolation between electronic medical system and human body (including tissue, body fluids, etc.) is obtained. The hermetic packaging includes an electronic MEMS pressure sensor, power charging system, and bluetooth communication system to wirelessly measure variation of capacitance. The packaging was acquired by Quartz direct bonding and $CO_2$ laser welding, with a size of width $ 6cm{\times}length\;10cm{\times}lheight\;3cm$. Hermetic sealing of the packaged system was tested by changing the pressure in a hermetic chamber using a precision pressure controller, from atmospheric to 900 mmHg. We found that the packaged system retained the same count or capacitance values with sensor 1 - 25,500, sensor 2 - 26,000, and sensor 3 - 20,800, at atmospheric as well as 900 mmHg pressure for 5 hours. This result shows that the packaging method has perfect hermetic sealing in any environment of the human body pressure.