• Journal of Korean Neurosurgical Society
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• v.63 no.5
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• pp.671-672
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• 2020

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.294-301
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• 2017

This paper presents a low power ${\Sigma}{\Delta}$ modulator for an implantable chip to acquire a bio-signal such as EEG, DBS, and EMG. In order to reduce a power consumption of the proposed fourth order modulator, two op-amps utilized for the first two integrators are reconfigured to drive the second two integrators. The KT/C noise reduction circuit in the first two integrators is employed to enhance SNR of the modulator. The proposed circuit was fabricated in a 0.18 um CMOS n-well 1 poly 6 metal process with the active chip core area of $900um{\times}800um$ and the power consumption of 830 uW. Measurement results were demonstrated to be SNDR of 76 dB, DR of 77 dB, ENOB of 12.3 bit at the input frequency of 250 Hz and the clock frequency of 256 kHz. FOM1 and FOM2 were measured to be 41 pJ/step and 142.4 dB, respectively.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.762-766
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• 1998

Mechanical valve is one of the most widely used implantable artificial organs, Since its failure (mechanical failures and thrombosis to name two representative example) means the death of patient, its reliability is very important and early noninvasive detection is essential requirement . This paper will explain the method to detect the thrombosis formation by spectral analysis and neural network. In order quantitatively to distinguish peak of a normal valve from that of a thrombotic valve, a 3 layer backpropagation neural network, which contains 7,000 input nodes, 20 hidden layer and 1output , was employed. The trained neural network can distinguish normal and thrombotic valve with a probability that is higher than 90% . In conclusion, the acoustical spectrum analysis coupled with a neural network algorithm lent itself to the noninvasive monitoring of implanted mechanical valves. This method will be applied to be applied to the performance evaluation of other implantable rtificial organs.

• Transactions on Electrical and Electronic Materials
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• v.15 no.2
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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.

• Journal of Biomedical Engineering Research
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• v.29 no.6
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• pp.415-430
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• 2008

The technologies in medical electronic implant(MEI) devices are developing rapidly, and already, there are various kinds of the MEI devices in the current medical equipments market. Recently, the global market scale of MEI devices have been increased about 13% year by year, and the import amount of MEI devices in Korea is increasing rapidly. In the near future, the demands of MEI devices will be magnificently increasing by the continuous development of the biomedical electronics devices which coupled with neural, brain and other organs will bring us to tremendous effects, such as providing new therapeutic solutions to patients, extension and saving human life, and an important clue of medical development. However, the investment of the research and the activity of developments in this field are still very weak in the Korea. Consequently, this paper introduces about the research trends of MEI devices, and technological problems those must be solved, and then concludes with the suggestions in order to be the leading country in this field.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1305-1308
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• 1987

This paper presents a design of an optimized implantable biotelemetry system and the fabrication of custom CMOS LSI for implementing this system. The internal circuits of this system are fabricated on a single silicon chip with a size of $4{\times}5mm^2$. This LSI is designed and fabricated not only to get as small size and low power dissipation as possible, but also to have multiple function. Its main functions are to select one of implanted sensors and to accomplish ON - OFF power switching of an implanted battery by receiving appropriate Command signals and control signals fran external circuits. The internal system which was assembled on a bread-board using fabricated LSI chip is confirmed to work as designed. The total power dissipation of this interal system was $10.12{\mu}W$.

• Transactions on Electrical and Electronic Materials
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• v.16 no.5
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.112-115
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• 2016

This paper demonstrates a scalp-implantable miniaturized antenna at the medical implant communication service (MICS) (402-405MHz) band. The antenna size is only $27.63mm^3$($8.5mm{\times}6.5mm{\times}0.5mm$), which is the smallest antenna for the MICS band. Miniaturization is achieved by using a symmetrical serpentine shaped radiating patch and placing open-end slots in the ground plane. In addition, co-axial feeding is used for excitation with a shorting pin connected between the radiator and ground. The antenna was simulated in a homogeneous skin model and in the human scalp. An experimental prototype of the proposed antenna was fabricated and measured in a skin-mimicking gel. Good agreement was obtained between the measurement and simulation results, showing a broad bandwidth of 49 MHz (from 395 to 444 MHz) for |S11| less than -10 dB and a maximum gain of -42.87 dBi. This gain is higher than the previous MICS antenna with respect to antenna size.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2004.11a
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• pp.3-4
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• 2004

A flexible Packaging scheme, which embedded chip packaging, has been developed using a thinned silicon chip. Mechanical characteristics of thinned silicon chips are examined by bending test and finite element analysis. Thinned silicon chips ($t<50{\mu}m$) are fabricated by chemical etching process to avoid possible surface damages on them. These technologies can be use for a real-time monitoring of blood pressure. Our research targets are implantable blood pressure sensor and its telemetric measurement. By winding round the coronary arteries, we can measure the blood pressure by capacitance variation of blood vessel.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.758-761
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• 1991

Using one chip microcontroller 87Cl96 (On chip EPROM type) and EPLD (Erasable & Programable Logic Device), an implantable control system to drive pendulum type electromechanical total artificial heart was developed. This control system consists of 4 parts, main management system, motor driver with power regulator, state monitoring system and communication part. The main system has the functions for speed detection, PI(proportional and integration) control, PWM generation, communication and analog data processor. Two kinds of power system were used and separated by 8 photo coupler arrays to improve the system stability. The performances of each compartments were compared with our previous z80 microprocessor based control system and good correspondences was shown. Logic power consumption was reduced to a one third of our previous controller. Using mock circulation tests, the overall performances of control system are evaluated.