• Journal of electromagnetic engineering and science
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• v.11 no.2
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• pp.76-82
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• 2011

In this paper, a novel design for a dual-band negative group delay circuit (NGDC) is proposed. Composite right/left-handed (CRLH) ${\lambda}/4$ short stubs are employed as a dual-band resonator. A CRLH ${\lambda}/4$ short stub is composed of a typical transmission line element as the right-handed component and a high-pass lumped element section as the left-handed component. It is possible to simultaneously obtain open impedances at two separate frequencies by the combination of distinctive phase responses of the right/left-handed components. Negative group delay (NGD) can be obtained at two frequencies by using dual-band characteristics of the CRLH stub. In order to achieve a bandwidth extension, the proposed structure consists of a two-stage dual-band NGDC with different center frequencies connected in a cascade. According to the experiment performed, with wide-band code division multiple access (WCDMA) and worldwide interoperability for microwave access (WiMAX), NGDs of $-3.0{\pm}0.4$ ns and $-3.1{\pm}0.5$ ns are obtained at 2.12~2.16 GHz and 3.46~3.54 GHz, respectively.

• Journal of the Korea Society of Computer and Information
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• v.13 no.4
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• pp.87-95
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• 2008

In this paper, we developed a selectable observation Point test architecture and test procedure for clocked 4-bit synchronous counter circuit based on boundary scan architecture. To develope, we analyze the operation of Sample/Preload instruction on boundary scan architecture. The Sample/Preload instruction make Possible to snapshot of outputs of CUT(circuit under test) at the specific time. But the changes of output of CUT during normal operation are not possible to observe using Sample/Preload in typical scan architecture. We suggested a selectable observation point test architecture that allows to select output of CUT and to observe of the changes of selected output of CUT during normal operation. The suggested a selectable observation point test architecture and test procedure is simulated by Altera Max 10.0. The simulation results of 4-bit counter shows the accurate operation and effectiveness of the proposed test architecture and procedure.

• Journal of Life Science
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• v.13 no.4
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• pp.448-456
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• 2003

The purpose of this study was to determine changes in their cardiorespiratory function and body composition in female workers after aerobic exercise and circuit weight training. The subjects of this study were 16 female workers in B city and was divided into exercise and control groups which were composed of 8 people respectively. The members of exercise group had aerobic exercise and circuit weight training an hour a day, 5 days per week, for 8 weeks while controled group did not. Both groups were pretested and posttested, and the results of this study on cardiorespriatory function and body composition are as follows. Exercise group showed significant decrease in heart rate at rest(p<.001). Exercise group showed significant increase in the oxygen uptake at rest, in the maximum oxygen uptake and in the vital capacity(p<.001). Exercise group showed significant decrease in the %fat and fat(p<.001). Exercise group showed significant increase in the %LBM and LBM(p<.001).

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.11
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• pp.21-27
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• 2004

In this paper, millimeter-wave monolithic integrated circuit(MIMIC) low noise amplifier(LNA) for V-band, which is applicable to 60 GHz wireless local area network(WLAN), was fabricated using the high performance 0.1 ${\mu}{\textrm}{m}$ $\Gamma$-gate pseudomorphic high electron mobility transistor(PHEMT). The DC characteristics of PHEMT are drain saturation current density(Idss) of 450 mA/mm and maximum transconductance(gm, max) of 363.6 mS/mm. The RF characteristics were obtained the current gain cut-off frequency(fT) of 113 GHz and the maximum oscillation frequency(fmax) of 180 GHz. V-band MIMIC LNA was designed using active and passive device library, which is composed of 0.1 ${\mu}{\textrm}{m}$ $\Gamma$-gate PHEMT and coplanar waveguide(CPW) technology. The designed V-band MIMIC LNA was fabricated using integrated unit processes of active and passive device. The measured results of V-band MIMIC LNA are shown S21 gain of 21.3 dB, S11 of -10.6 dB at 60 GHz and S22 of -29.7 dB at 62.5 GHz. The measured result of V-band MIMIC LNA was shown noise figure (NF) of 4.23 dB at 60 GHz.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.1
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• pp.39-44
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• 2008

In this paper, fully embedded 2.4GHz WLAN band pass filter (BPF) was investigated into a multi-layered organic packaging substrate using high Q spiral stacked inductors and high Dk MIM capacitors for low cost RF System on Package (SOP) applications. The proposed 2.4GHz WLAN BPF was designed by modifying chebyshev second order filter circuit topology. It was comprised of two parallel LC resonators for obtaining two transmission zeros. It was designed by using 2D circuit and 3D EM simulators for finding out optimal geometries and verifying their applicability. It exhibited an insertion loss of max -1.7dB and return loss of min -l7dB. The two transmission zeros were observed at 1.85 and 6.7GHz, respectively. In the low frequency band of $1.8GHz{\sim}1.9GHz$, the stop band suppression of min -23dB was achieved. In the high frequency band of $4.1GHz{\sim}5.4GHz$, the stop band suppression of min -l8dB was obtained. It was the first embedded and the smallest one of the filters formed into the organic packaging substrate. It has a size of $2.2{\times}1.8{\times}0.77mm^3$.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.3
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• pp.232-238
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• 2008

In this paper, a wideband power efficient 2.2 GHz - 4.9 GHz Medium Power Amplifier (MPA), has been designed and fabricated using $0.8{\mu}m$ SiGe BiCMOS process technology. Passive elements such as parallel-branch spiral inductor, metal-insulator-metal (MIM) capacitor and three types of resistors are all integrated in this process. This MPA is a two stage amplifier with all matching components and bias circuits integrated on-chip. A P1dB of 17.7 dBm has been measured with a power gain of 8.7 dB at 3.4 GHz with a total current consumption of 30 mA from a 3 V supply voltage at $25^{\circ}C$. The measured 3 dB bandwidth is 2.7 GHz and the maximum Power Added Efficiency (PAE) is 41 %, which are very good results for a fully integrated Medium PA. The fabricated circuit occupies a die area of $1.7mm{\times}0.8mm$.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.9 s.339
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• pp.1-8
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• 2005

A $0.35\mu$m SiGe BiCMOS fabrication process has been timely developed, which is aiming at wireless RF ICs development and fast growing SiGe RF market. With non-selective SiGe epilayer, SiGe HBTs in this process used trapezoidal Ge base profile for the enhanced AC performance via Ge induced bandgap niuoin. The characteristics of hFE 100, $f_{T}\;45GHz,\;F_{max}\;50GHz,\;NF_{min}\;0.8dB$ have been obtained by optimizing not only SiGe base profile but also RTA condition after emitter polysilicon deposition, which enables the SiGe technology competition against the worldwide cutting edge SiGe BiCMOS technology. In addition, the process incorporates the CMOS logic, which is fully compatible with $0.35\mu$m pure logic technology. High Q passive elements are also provided for high precision analog circuit designs, and their quality factors of W(1pF) and inductor(2nH) are 80, 12.5, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.713-715
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• 2012

본 논문은 24GHz 차량 추돌 예방 레이더 시스템-온-칩을 위한 입력 임피던스, 전압이득 및 잡음지수를 자동으로 측정할 수 있는 새로운 형태의 고주파 자체 내부검사(BIST, Built-In Self-Test) 회로를 제안한다. 이러한 BIST 회로는 TSMC $0.13{\mu}m$ 혼성신호/고주파 CMOS 공정 ($f_T/f_{MAX}$=140/120GHz)으로 설계되어 있다. 알고리즘은 LabVIEW로 구현되어 있다. BIST 알고리즘은 입력 임피던스 정합과 출력 직류 전압 측정원리를 이용한다. 본 논문에서 제안하는 방법은 자동으로 쉽게 고주파 회로의 성능변수를 측정할 수 있기 때문에 시스템-온-칩의 저가 성능 검사의 대안이 될 것으로 기대한다.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.4
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• pp.5-21
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• 1994

We have described the optimal process route selection model for the PCB(printed circuit board) auto-insertion line. This PCB assembly line is known as a FFL(flexible flow line) which produces a range of products keeping the flow shop properties. Under FFL environments, we have emphasized the balancing of work-loads in order to maximize total productivity of PCB auto-insertion line. So we have developed a heuristic algorithm based on a work-order selection rule and min-max concept for the job route selection model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.158-162
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• 1995

We report rf and power characteristics of AlGaAs/GaAs Heterojunction Bipolar Transistor (HBTs) for X-band power applications. HBTs have been fabricated with polyimide a an interlayer dielectric. By characterizing the DC and RF characteristics we obtained the maximum current gain of 45, BV$\_$CEO/ of 10 V, fT of 30 GHz and f$\_$max/ of 17 GHz for device with 6x14$\mu\textrm{m}$$^2$emitter size. To extract accurate equivalent parameters, the De-embedded method was applied for extraction of parasitic parameters and the calculation of circuit equations for intrinsic parameters. Based on the Load-pull method, power characteristics was simulated and measured to get the maximum output power of the device.