• JSTS:Journal of Semiconductor Technology and Science
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• 제16권5호
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• pp.675-681
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• 2016

A 41dB gain control range $6^{th}$-order band-pass receiver front-end (RFE) using CMOS switched frequency translated impedance (FTI) is presented in a 40 nm CMOS technology. The RFE consists of a frequency tunable RF band-pass filter (BPF), IQ gm cells, and IQ TIAs. The RF BPF has wide gain control range preserving constant filter Q and pass band flatness due to proposed pre-distortion scheme. Also, the RF filter using CMOS switches in FTI blocks shows low clock leakage to signal nodes, and results in low common mode noise and stable operation. The baseband IQ signals are generated by combining baseband Gm cells which receives 8-phase signal outputs down-converted at last stage of FTIs in the RF BPF. The measured results of the RFE show 36.4 dB gain and 6.3 dB NF at maximum gain mode. The pass-band IIP3 and out-band IIP3@20 MHz offset are -10 dBm and +12.6 dBm at maximum gain mode, and +14 dBm and +20.5 dBm at minimum gain mode, respectively. With a 1.2 V power supply, the current consumption of the overall RFE is 40 mA at 500 MHz carrier frequency.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.219-222
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• 2003

In this paper, we designed a Ku-band BPF(Band Pass Filter) by microstrip line that most usually used a microwave device design and fabrication. Here a substrate of designed BPF were silicon substrate(${\varepsilon}_r=11.8$), and metal line was copper and silver/copper structure. And a configration of BPF was used hairpin pattern. A center frequency of designed BPF was 10GHz and their FBW(Fractional Band Width) was 20%(2GHz). It presented simulated results obtained for a 10GHz filter which yields an insertion loss of 0.1dB that ripple value related chebyshev reponse. Finallt we tried to make that a 30dB attenuation frequency was 20% of center frequency.

• 대한조선학회논문집
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• 제48권4호
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• pp.299-307
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• 2011

The offshore plants such as FPSO are subjected to combination loading of environmental conditions (swell, wave, wind and current). Therefore the fatigue damage is occurred in the operation time because the units encounter the environmental phenomena and the structural configurations are complicated. This paper is a research for frequency domain fatigue analysis of wide-band random loading focused on accuracy of fatigue damage estimation regarding the proposed methods. We selected ideal bi-modal spectrum. And comparison between time-domain fatigue analysis and frequency-domain fatigue analyses are conducted through the fatigue damage ratio. Fatigue damage ratios according to Vanmarcke's bandwidth parameter are founded for wide-band. Considering safety, we recommend that Jiao-Moan and Tovo-Benasciutti methods are optimal way at the fatigue design for wide-band response. But, it is important that these methods based on frequency-domain unstably change the accuracy according to the material parameter of S-N curve. This study will be background and guidance for the new frequency-domain fatigue analysis development in the future.

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권4호
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• pp.192-197
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• 2009

This paper presents the design and measurement of a 2.4/5.2-GHz dual band VCO with a balanced frequency doubler in $0.18\;{\mu}m$ CMOS process. The topology of a 2.4 GHz VCO is a cross-coupled VCO with a LC tank and the frequency of the VCO is doubled by a frequency balanced doubler for a 5.2 GHz VCO. The gate bias matching network for class B operation in the balanced doubler is adopted to obtain as much power at 2nd harmonic output as possible. The average output powers of the 2.4 GHz and 5.2 GHz VCOs are -12 dBm and -13 dBm, respectively, the doubled VCO has fundamental harmonic suppression of -25 dB. The measured phase noises at 5 MHz frequency offset are -123 dBc /Hz from 2.6 GHz and -118 dBc /Hz from 5.1 GHz. The total size of the dual band VCO is $1.0\;mm{\times}0.9\;mm$ including pads.

• 한국정보통신학회논문지
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• 제7권4호
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• pp.598-603
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• 2003

본 논문에서는 주파수 부대역마다 최적의 특징추출을 위해서, 음성인식률을 기준으로 최적의 방법을 선택한다. 다중대역 음성인식 접근을 사용하여 각기 다른 주파수 영역에서 특징벡터를 독립적으로 추출함으로써 부대역별로 다른 특징추출 방법을 적용할 수 있었다. 저주파 대역의 음성은 비교적 스펙트럼의 구조가 명확하므로 전극모델을 사용하는 것이 효과적이었고, 고주파 대역에서는 비모수적인 변환방법인 이산 코사인 변환을 사용한 켑스트럼이 효과적이었다. 부대역별로 효과적인 특징추출 방법을 사용함으로써, 각 주파수 부대역에 포함된 음성인식을 위한 언어정보를 보다 효과적으로 추출할 수 있었다. 음성인식 실험결과, 제안한 방법은 전대역 특징추출보다 우수한 성능을 나타내었다.

• Journal of Astronomy and Space Sciences
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• 제18권2호
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• pp.119-128
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• 2001

도파관형 건 발진기의 발진주파수 범위와 주파수 안정도는 공진기 치수에 따른 임피던스에 민감하다. 그러므로 HFSS (High Frequency Structure Simulator)을 이용하여 공진기의 치수에 따른 임베딩 임피던스 (embedding impedance)를 계산하였다. 본 논문에서는 주파수 함수를 갖는 Q-band (33 ∼ 50 GHz) 건 발진기의 임베딩 임피던스의 이론적인 결과와 실제 제작한 발진기의 실험측정 결과를 비교하여 이론적 해석의 타당성을 검증하였다. 그리고 본 논문에서 제시한 방법에 의한 이론적 해석만으로 발진주파수 범위를 예상할 수 있음을 확인하였다

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.290-292
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• 2009

With advance in technologies for wireless sensor networks(WSNs), 2.4 GHz band has become gradually attractive due to increase in low-power wireless communication devices. Especially ZigBee(IEEE 802.15.4-based) technology whose frequency band includes the 2.4GHz industrial, scientific and medical band providing nearly worldwide availability has been universally applicable to a various remote monitoring system and applications related home network system. However network throughput of these systems is significantly deteriorated due to this ISM band is a license-exemption used in a variety of low-power wireless communication devices. For instance, other IEEE 802 wireless standards such as Bluetooth, WLAN, Wi-Fi and others cause radio interference to ZigBee. The experiments was carried out to analyze radio frequency interference between heterogeneous devices using ISM bands to improve the limited frequency utility factor. Finally this paper suggests a frequency hopping-based adaptive multi-channel methods to decrease interference with empirical results.

• 한국산업융합학회 논문집
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• 제8권2호
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• pp.97-104
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• 2005

Usually, propagation attenuation of millimeter wave occurs by rainfall, snowfall, temperature, effect of pressure of air. In 60GHz wave band wireless communication network, temperature change becomes big factor of propagation loss department. Also, temperature change causes disturbance of 60GHz frequency at transceiver. In this study, we used 60GHz transceiver and found propagation loss of wireless path and operating frequency disturbance characteristics. In transceiver that there is no temperature compensated device, operating frequency of TX changed by 60.865GHz at temperature of $-5^{\circ}C$, and appeared by 60.730GHz when is $50^{\circ}C$. Therefore, operating frequency change width by temperature change are about 100MHz, greatly. But, in transceiver that there is temperature compensated device, operating frequency of TX changed by 60.830GHz at temperature of $-5^{\circ}C$, and appeared by 60.710GHz when is $50^{\circ}C$. Therefore, operating frequency change width by temperature change are about 20MHz. According to these result, we constructed between buildings examination wireless site for point to point wireless communication using 60GHz band transceivers who have do temperature compensated device, and investigated data transmission characteristics about ambient temperature change. Therefore, if use transceiver that have temperature compensated device, may overcome the wireless transmission error in 60GHz band wireless communication LAN networks despite of ambient temperature change.

• 한국전자파학회논문지
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• 제18권5호
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• pp.511-521
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• 2007

본 논문에서는 복합 소형화된 Ka-대역 주파수 합성기 모듈을 제작하였다. 본 논문을 통하여 소형화 구성시 배치 방법과 체계적인 검증 방법을 제시하였다. 제작된 주파수 합성기는 X-대역 전압 제어 발진기(VCO: Voltage Controlled Oscillator)의 주파수를 3체배하여 구성하였으며, 제작된 모듈은 500 MHz 주파수 가변 범위와 약 14 dBm의 출력 전력, 그리고 100 kHz 오프셋 주파수에서 -96.17 dBc/Hz의 위상 잡음 특성을 보여주고 있다.

• 한국전자파학회논문지
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• 제20권10호
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• pp.1107-1113
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• 2009

본 논문에서는 K-Band에서 동작하는 1/2 주파수 분배기를 130 nm CMOS 공정을 이용하여 설계하고 제작한 결과를 보인다. 피드백 방식의 밀러 주파수 분배기는 20~25 GHz에서 동작하며 바이어스 전압 1.2 V에서 7.2 mW의 전력을 소모하고 코어 회로의 레이아웃 크기는 $315{\times}246\;um^2$이다. 밀러 주파수 분배기의 출력 신호를 2분 주시키기 위한 CML(Current Mode Logic) 주파수 분배기는 8.5~13 GHz에서 동작하며 5.7 mW의 전력을 소모하고, 코어 회로의 레이아웃 크기는 $91{\times}98\;um^2$이다. 또한 두 주파수 분배기를 결합하여 20~25 GHz의 입력 신호가 4분주되어 출력됨을 확인하였다.