• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1406-1407
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• 2008

In this paper, a micro balanced filter in magnetically coupled LC resonators is proposed, designed, simulated by using FR-4 PCB substrate for low cost, small volume IEEE 802. 11a wireless LAN application. Two pair of coupled LC resonators using magnetic coupling of embedded inductors are applied to obtain bandpass transmission response and improve their phase and magnitude imbalance characteristics. In addition, high dielectric composite film is applied to fabricate the high Q MIM capacitors with small size and high capacitance density. It has an insertion loss of 1.4 dB, a return loss of 10 dB, a phase imbalance of 0.25 degree, and magnitude imbalance of 0.17 dB at frequency bandwidth of 200 MHz ranged from 5.15 GHz to 5.35 GHz, respectively. The proposed balanced filter has a small volume of $1.1mm{\times}1.3mm{\times}0.6mm$ (height).

• 한국공작기계학회논문집
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• 제16권6호
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• pp.201-204
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• 2007

In this paper, fully embedded and miniaturized diplexer device has been developed and characterized for dual-band/mode CDMA handset applications. The size of the embedded diplexer is significantly reduced by embedding high Q circular spiral inductors and high DK MIM capacitors into a low cost organic package substrate. The fabricated diplexer has insertion losses and isolations of -0.5 and -23 dB at 824-894 MHz and -0.7 and -22 dB at 1850-1990 MHz, respectively. Its size is $3.9mm{\times}3.9mm{\times}0.77mm$. The fabricated diplexer is the smallest one which is fully embedded into a low cost organic package substrate.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.262-263
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• 2007

In this paper, fully embedded and miniaturized diplexer has been designed, fabricated, and characterized for dual-band/mode CDMA handset applications. The size of the embedded diplexer is significantly reduced by embedding high Q circular spiral inductors and high DK MIM capacitors into low cost organic package substrate. The fabricated diplexer has insertion losses and isolations of -0.5 and -23dB at 824-894MHz and -0.7 and -22dB at 1850-1990MHz, respectively. Its size is 3.9mm$\times$3.9mm$\times$ 0.77mm (height). The fabricated diplexer is the smallest one which is fully embedded into low cost organic package substrate.

• 한국전자파학회논문지
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• 제15권7호
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• pp.713-721
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• 2004

본 논문은 InGaP/GaAs HBT를 사용하여 5.4㎓ 대역의 고성능 저잡음 증폭기를 제안하였다. 기존에 InGaP/GaAs HBT는 고전력 증폭기 설계에 주로 사용되어 왔으나, 최근 RF 단일칩화를 위한 소자로 인식되고 있다. 이에 InCaP/GaAs HBT 소자를 이용한 저잡음 증폭기 설계에 대한 연구가 선행되어야 하며, 본 논문에서는 InGaP/GaAs HBT의 우수한 선형성 특성과 잡음 특성을 이용하여 뛰어난 성능의 저잡음 증폭기를 설계 및 제작하였다. 제안된 저잡음 증폭기는 높은 Q의 나선형 인덕터와 MIM 형태의 캐패시터 등의 수동 소자와 능동 소자가 모두 한 칩에 집적화 되어 입출력 패드와 함께 0.9${\times}$0.9$\textrm{mm}^2$의 면적에 집적화 되었다. 제안된 저잡음 증폭기는 최적의 동작점을 선택해 이득과 잡음 지수를 최적화하였으며, 더불어 우수한 선형성을 얻을 수 있었다. 측정결과 제작된 저잡음 증폭기는 13㏈의 이득과 2.1㏈의 우수한 잡음 지수를 보였으며, IIP3 5.5㏈m의 우수한 선형성이 측정되었다.

• 한국재료학회지
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• 제17권11호
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• pp.574-579
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• 2007

Amorphous $BaTi_4O_9$ ($BT_4$) film was deposited on Pt/Si substrate by RF magnetron sputter and their dielectric properties and electrical properties are investigated. A cross sectional SEM image and AFM image of the surface of the amorphous $BT_4$ film deposited at room temperature showed the film was grown well on the substrate. The amorphous $BT_4$ film had a large dielectric constant of 32, which is similar to that of the crystalline $BT_4$ film. The leakage current density of the $BT_4$ film was low and a Poole-Frenkel emission was suggested as the leakage current mechanism. A positive quadratic voltage coefficient of capacitance (VCC) was obtained for the $BT_4$ film with a thickness of <70 nm and it could be due to the free carrier relaxation. However, a negative quadratic VCC was obtained for the films with a thickness ${\geq}96nm$, possibly due to the dipolar relaxation. The 55 nm-thick $BT_4$ film had a high capacitance density of $5.1fF/{\mu}m^2$ with a low leakage current density of $11.6nA/cm^2$ at 2 V. Its quadratic and linear VCCs were $244ppm/V^2$ and -52 ppm/V, respectively, with a low temperature coefficient of capacitance of $961ppm/^{\circ}C$ at 100 kHz. These results confirmed the potential suitability of the amorphous $BT_4$ film for use as a high performance metal-insulator-metal (MIM) capacitor.

• 한국정보통신학회논문지
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• 제11권10호
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• pp.1899-1909
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• 2007

본 논문에서는 TFT-LCD 구동 IC 모듈의 소형화 측면에서 유리한 DC-DC 변환기 회로인 펌핑 커패시터 내장형 크로스-커플드 전하펌프(Cross-Coupled Charge Pump with Internal Pumping Capacitor) 회로가 새롭게 제안되었다. VGH 및 VGL 전하펌프 각각의 입력단과 전하 펌핑 노드를 연결하는 NMOS 및 PMOS 다이오드를 두어, 초기 동작 시 전하 펌핑 노드를 서로 같은 값으로 프리차지하여 대칭 적으로 전하 펌핑을 하도록 하였다. 그리고 첫 번째 전하 펌프의 구조를 다르게 설계하여 펌핑된 전하가 입력단으로 역류되는 현상을 방지하였다. 또한, 펌핑 클럭 구동 드라이버의 위치를 펌핑 커패시터 바로 앞에 두어 기생 저항으로 인한 펌핑 클럭 라인의 전압강하를 방지하여 구동능력을 향상 시켰다. 마지막으로 내장형 펌핑 커패시터를 Stack-MIM 커패시터를 사용하여 기존의 크로스-커플드 전하펌프 보다 레이아웃 면적을 최소화하였다. 제안된 TFT-LCD 구동 IC 용 전하펌프 회로를 $0.13{\mu}m$ Triple-Well DDI 공정을 사용하여 설계하고, 테스트 칩을 제작하여 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.2108-2110
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• 2004

In this paper, a novel tunable bandpass filter using tunable series inductors and MEMS switches for wireless LAN applications was proposed. The proposed tunable filter was fabricated using a micromachining technology and performances of the fabricated filter were estimated. The filter consists of spiral inductors, MIM capacitors and direct-contact type MEMS switches, and its frequency tunability is achieved by changing the inductance that is induced by ON/OFF actuations of the MEMS switches. The actuation voltage of the MEMS switches was 58 V, and the measured center frequencies were 2.55 GHz and 5.1 GHz, respectively. The passband insertion loss and 3-dB bandwidth were 4.2 dB and 22.5 % at 2.55 GHz, and 5.2 dB and 23.5 % at 5.1 GHz, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1929_1930
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• 2009

Fully embedded tunable bandpass filter (BPF) with inductive coupling circuits is newly designed and demonstrated for UHF TV tuner ranged from 500MHz to 900MHz receivers. Conventional RF tuning circuit with an electromagnetic coupled tunable filter has several problems such as large size, high volume, and high cost, since the electromagnetic coupled filter is comprised of several passive components and air core inductors to be assembled and controlled manually. To address these obstacles, compact tunable filter with inductive coupling circuit was embedded into low cost organic package substrate. The embedded filter was optimally designed to have high performance by using high Q spiral stacked inductors, high dielectric $BaTiO_3$ composite MIM capacitors, varactor diodes. It exhibited low insertion loss of approximately -2dB, high return loss of below -10dB, and large tuning range of 56.3%. It has an extremely compact size of $3.4{\times}4.4{\times}0.5mm^3$.

• Journal of Korean Vacuum Science & Technology
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• 제6권3호
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• pp.126-132
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• 2002

The origin of image-sticking in metal-insulator-metal type thin-film diode liquid crystal displays(TFD-LCDs) is the asymmetric current-voltage(I-V) characteristic of TFD element. We developed that TFD-LCDs have reduced-image-sticking. Tantalum pentoxide(Ta$_2$O$\sub$5/) is a candidate for use in metal-insulator-metal(MIM) capacitors in switching devices for active-matrix liquid crystal displays(AM-LCDs). High quality Ta$_2$O$\sub$5/ thin films have been obtained from anodizing method. We fabricated a TFD element using Ta$_2$O$\sub$5/ films which had perfect current-voltage symmetry characteristics. We applied novel process technologies which were postannealed whole TFD element instead of conventional annealing to the fabrication. One-Time Post-Annealing(OPTA) heat treatment process was introduced to reduce the asymmetry and shift of the I-V characteristics, respectively. OPTA means that the whole layers of lower metal, insulator, and upper metal are annealed at one time. Futhermore, in this paper, we discussed the effects of top-electrode metals and annealing conditions.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2004년도 하계학술대회
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• pp.11-14
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• 2004

In this paper, a novel tunable bandpass filter using tunable series inductors and MEMS switches for wireless LAN applications was proposed. The proposed tunable filter was fabricated using a micromachining technology and performances of the fabricated filter were estimated. The filter consists of spiral inductors, MIM capacitors and direct-contact type MEMS switches, and its frequency tunability is achieved by changing the inductance that is induced by ON/OFF actuations of the MEMS switches. The actuation voltage of the MEMS switches was 58 V, and the measured center frequencies were 2.55 GHz and 5.1 GHz, respectively. The passband insertion loss and 3-dB bandwidth were 4.2 dB and 22.5 % at 2.55 GHz, and 5.2 dB and 23.5 % at 5.1 GHz, respectively.