• 한국산학기술학회논문지
• /
• 제12권9호
• /
• pp.4101-4106
• /
• 2011

본 논문에서 기존 underpass와 via를 갖는 단층 나선형 박막 인덕터를 확장하여 제한된 점유면적 내에서 인덕턴스를 증가시킬 수 있는 하층 나선형 코일과 via를 갖는 2층 나선형 박막 인덕터의 구조를 제안하고 주파수 특성을 확인하였다. 인덕터의 구조는 Si를 $300{\mu}m$, $SiO_2$를 $7{\mu}m$으로 하였으며, Cu 코일의 폭과 선간의 간격은 각각 $20{\mu}m$으로 설정하여 3회 권선하였다. 나선형 박막 인덕터의 성능을 나타내는 인덕턴스, quality-factor, SRF에 대한 주파수 특성을 HFSS로 시뮬레이션 하였다. 2층 나선형 박막 인덕터는 0.8~1.8GHz 범위에서 3.2nH의 인덕턴스, 2.5GHz에서 최대 8.2 정도의 품질계수를 가지며, SRF는 5.8GHz로 시뮬레이션 결과를 얻었다. 반면에 단층 나선형 박막 인덕터는 0.8~1.8GHz 범위에서 1.5nH의 인덕턴스, 8GHz에서 최대 18 정도의 품질계수를 가지며, SRF는 19.2GHz로 시뮬레이션 결과를 얻을 수 있었다.

• 센서학회지
• /
• 제20권4호
• /
• pp.238-242
• /
• 2011

This paper describes the fabrication and characteristics of a low frequency vibration driven electromagnetic energy harvester. The fabricated generator consists of a permanent magnet of NdFeB, a FR-4 planar spring and a Copper cylinder type coil. ANSYS modal analysis was used to determine the resonant frequency for the generator. The implemented generator is capable of producing up to 550 mV peak-to-peak under 7 Hz frequency, which has a maximum power of $95.5\;{\mu}W$ with load resistance of $580\;{\Omega}$. This device is shown to generate sufficient power at different resonating modes, and the experimental and simulated results are discussed and composed.

• 대한의용생체공학회:의공학회지
• /
• 제20권5호
• /
• pp.537-544
• /
• 1999

자기공명영상시스템의 경사자계코일을 영구자석의 자극에 부착할 경우 경사자계의 분포가 변하고 코일의 인덕턴스가 증가하는 현상이 생긴다. 본 논문에서는 이러한 자극효과를 고려하여 평면형 경사자계코일을 설계하는 방법을 제시하였다. 제사한 방법에는 자극 효과를 거울 전류로 모델링하였고, 모델링한 거울 전류를 고려하여 경사자계코일의 인덕턴스를 최소화하는 방법을 구했다. 또한 실제 상황과 가장 흡사한 자계 분포를 만들어주는 거울 전류의 크기를 구하기 위해 유한요소법을 적용하였다. 제시한 방법으로는 설계된 경사자계코일은 종래의 설계된 경사자계 코일에 비해 우수한 성능을 보였다.

• 센서학회지
• /
• 제21권4호
• /
• pp.298-302
• /
• 2012

This paper describes the design and fabrication of a low frequency vibration driven high-efficiency electromagnetic energy harvester based on FR(Flame Resistance)-4 spring which converts mechanical energy into useful electrical power. The fabricated generator consists of a vertically polarized NdFeB permanent magnet attached to the center of spring and a planar type copper coil which has higher efficiency compare with cylindrical type coil. ANSYS finite analysis and Matlab were used to determine the resonance frequency and output power. The generator is capable of producing up to 1.36 $V_{pp}$ at 9 Hz, which has the maximum power of 639 ${\mu}W$ with a load resistance of $3.25k{\Omega}$.

• 대한기계학회논문집A
• /
• 제25권11호
• /
• pp.1863-1872
• /
• 2001

In this Paper, we suggest the precision stage using a novel non-contact planar actuator that utilizes an interaction between an array type of air-core solenoids and permanent magnets. The former with axes arranged in the mutually orthogonal direction is fixed on the stator and the latter with the same polar direction is attached below the stage. The promising magnetic structure has little uncertainty such as hysteresis loss caused by ferromagnetic material, then it is simple to quantify the magnetic phenomenon. And all the magnetic forces are transmitted through narrow air-gap between the coil and the permanent magnet, therefore the structure can be highly compacted. Furthermore, the stage or plate can be perfectly isolated from the stator without any wire connection, leading to diminish the generating possibility of wear particles due to mechanical contact. Then. it is estimated that the proposed operating principle is very suitable for work requiring high accuracy and cleanness. or general-purpose nano stage. The main issues rebated to the plate driving are discussed here.

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
• /
• pp.532-538
• /
• 2000

A double rectangular spiral inductor is fabricated using FeTaN films. The inductor is composed of internal coils sandwiched by magnetic layers. Characteristics of inductor performance are investigated with an emphasis on planarization of magnetic films. In the absence of the planarization process, the grating topology of upper magnetic films over coil arrays degrades the soft magnetic properties and the inductor performance. It also induces a longitudinal magnetic anisotropy with the easy axis aligned to the magnetic flux direction. This alignment prevents the upper magnetic films from contributing to the total induction. Glass bonding is a viable method for achieving a completely planar inductor structure. The planar inductor with glass bonding shows excellent performance : inductance of 1.1 H, Q factor of 7 (at 5 MHz), and the dc current capability up to 100 mA.

• 한국진공학회지
• /
• 제8권4A호
• /
• pp.461-464
• /
• 1999

Planar type thin film inductors have a potential for the application of miniaturized DC-DC converters. For those high current applications, the magnetic film with high current capability is required. The current capability of magnetic films is mainly determined from high saturation magnetization (4$\piM_s$) as well as large anisotropy field $(H_k)$. We fabricated a double rectangular spiral thin film inductor which consist of magnetic layer, coil and insulator. Highest inductance values as well as best frequency characteristics can be obtained from 5 MHz and quality factor exhibit about 7.

• 한국자기학회지
• /
• 제2권3호
• /
• pp.277-281
• /
• 1992

입력코일과 변조코일이 박막 형태로 집적화된 planar DC SQUID를 제작하고 그 특성을 조사하였다. SQUID loop은 균일한 외부자장의 영향을 받지 않도록 두개의 ring이 '8'자형으로 직렬로 연결된 구조를 하고 있으며, 조셉슨 접합으로는 Pd shunt 저항을 가지는 Nb/Al-oxide/Nb 턴넬 접합을 이용하였다. 소자는 포토리소그라피 기술과 RF 마그네트론 스퍼터링 및 양극산화 방법으로 제작하였으며, 제작된 SQUID는 4.2 K에서 기본적인 특성을 측정한 결과 standard readout 시스템에 적합한 매끄러운 특성을 보였으며 전압 잡음은 측정할 수 없을 정도로 작아 white noise는 최대 $10^{-4}\;{\phi}_o/\;\sqrt{H_z}$ 이하로 나타났다. 현재 matching 코일을 사용하여 잡음 특성을 측정중에 있으며 앞으로 SQUID parameter를 최적화할 경우 매우 고감도의 자기센서로 활용될 수 있을것으로 기대된다.

• 치과방사선
• /
• 제20권2호
• /
• pp.187-198
• /
• 1990

Examinations of the temporomandibular joints were performed on a 1.5 Tesla magnetic resonance (MR) system. An MR surface receiver coil 3 inch in diameter was placed on plastic frame, the patient's head being placed in the frame so that the coil was pressed against the temporal region. In taking advantage of the magnetic resonance imaging that has been studied briskly till now, author obtained the images of parasagittal and paracoronal planes about the temporomandibular joint by using MPGR (Multi-Planar Gradient Recalled), GRASS (Gradient Recalled Acquisition in the Steady State), and CSMEMP (Contiguous Slice Multiple Echo, Multi-Planar), that differ from the Spin Echo pulse sequence which the previous authors used. Five subjects with no symptoms of temporomandibular joint pain and dysfunction were studied. The plane images obtained by these methods were compared with those by Spin Echo pulse sequence. The results were as follows: 1. The optimal repetition times (TR) and echo times (TE) for T.M.J. image were; a. 400 msec and 18 msec in PMGR pulse sequence. b. 40 msec and 12 msec in GRASS pulse sequence. c. 700 msec and 30 msec in CSMEMP pulse sequence. d. 500 msec and 20 msec in Spin Echo pulse sequence. 2. When the MPGR pulse sequence was using, T2-weighted image was obtained in very short time. On the image of the paracoronal plane by GRASS pulse sequence, meniscus showed the moderate signal intensity, and the meniscus and its anteromedial, posterolateral attachments were observed definitely with gray color. 4. The signal intensity of Spin Echo pulse sequence was equal to that of CSMEMP pulse sequence, but the image by CSMEMP pulse sequence showed relatively lower level in its resolution.

• 한국자기학회지
• /
• 제12권3호
• /
• pp.109-116
• /
• 2002

평면변압기의 설계방법 확립과 응용가능성을 파악하기 위해 입/출력전압이 70V/8.2V인 8W급 플라이-백 평면변압기를 설계하였다. 스위칭 주파수 120kHz에서 인덕턴스는 1650 $\mu$H로서 이론치의 약 85%~87%인 인덕턴스 효율을 나타내었고, 도전체의 교류저항은 주파수가 증가할수록 증가하여 스위칭파수 120 kHz에서 1차/2차 코일의 교류저항이 각각 3.9 $\Omega$, 0.16 $\Omega$이었고, 성능지수는 각각 158, 75로 나타났으며, 결합인자 k값은 스위칭 주파수 120 kHz에서 0.96~0.97 범위의 값을 나타내었다. 또한 자성체의 평면부분의 두께가 1.4mm까지는 인덕턴스가 평면두께가 증가할수록 큰 폭으로 증가하였고, 1.4mm이상의 두께에서는 거의 일정한 값을 나타내어 자성체의 임계 평면두께는 1.4mm로 나타났다. 그리고 70V의 입력 전압에 대하여 안정한 구형파의 출력 파형을 나타내었다.