• Current Optics and Photonics
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• 제3권2호
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• pp.111-118
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• 2019

The optical characteristics of a tunable flattened-pass-band fiber comb filter, based on the polarization-diversified loop configuration, are investigated using the $Poincar{\acute{e}}$-sphere representation. In the design process, the spectral flatness is checked quantitatively, and the tunability of the pass band is demonstrated experimentally. Theoretical calculations show that the filter also exhibits desirable dispersion and polarization properties. The orientation angles of rotatable wave plates for the wavelength tunability of the filter are obtained. Furthermore, we elaborate on the multiple angle loci produced by degeneracies through the combination of optical elements within the loop of the filter.

• 전기학회논문지
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• 제61권11호
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• pp.1700-1705
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• 2012

This study is focusing on ripple elimination in the band pass filter. There are generally two design methods in IIR filter design, which are a direct method and an indirect one. The indirect design method that designs the digital IIR LPF using the prototype analog LPF is applied to this study. A Butterworth filter and a Chebyshev filter are the typical prototype analog LPFs. This study shows characteristics of the digital IIR LPFs that are transformed from the prototype analog LPFs. The designed Butterworth and Chebyshev IIR LPFs are also designed as the band pass filters by frequency transformation in order to compare with the proposed cascading Chebyshev BPFs. This study shows frequency characteristics between the transformed IIR BPFs and the proposed cascading Chebyshev BPFs as well. The proposed cascading Chebyshev BPF is designed by cascading the different orders of Chebyshev BPFs. The aspect of the cascading filter is offsetting the ripples to descend them while the pass band ripples of the Chebyshev filter are ascending and vice versa. The designed cascading Chebyshev filter shows the flatness and the sharpness, which represent the advantages of Butterworth filter in the pass band and of Chebyshev filter in the transition band respectively. This result verifies the validity of the designed filter.

• 한국전자파학회논문지
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• 제21권12호
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• pp.1467-1474
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• 2010

X 대역에서 능동 위상 배열 레이더에 적용할 수 있는 타일형 능동 송수신 모듈을 구현하였다. 제안한 타일형 구조의 구현을 위한 수직 연결은 fuzz button을 이용한 solderless 방식으로 삽입 손실은 0.6 dB, 반사 손실의 VSWR은 1.7 이하를 만족하며 X 대역에서 약 30 %의 대역폭을 가지는 광대역 특성을 가진다. 광대역 특성을 가지는 수직 연결 구조를 이용하면 수직 연결 시에 발생할 수 있는 부정합을 최소한으로 하여 우수한 이득 평탄도를 가지는 타일형 구조의 송수신 모듈을 구현할 수 있다.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.205-210
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• 2005

In this paper, a planar half-circle shape ultra-wideband(UWB) antenna fed by CPW is designed, fabricated and measured for UWB communications. Within the UWB band(3.1 GHz $\sim$ 10.6 GHz), 5.15 GHz $\sim$ 5.825 GHz frequency band is used by IEEE 802.lla WLAN applications. It may be necessary to notch out this band to avoid interference with IEEE 802.lla WLAN. Therefore, we have proposed three kinds of UWB antennas having a notch function, such as a rectangular slot, a hat-shaped slot, a circle-shaped slot. The notch frequency of the proposed antenna can be adjusted by controlling the slot length or slot width. From the measured results, the proposed antennas show a good gain flatness except the IEEE 802.lla WLAN frequency band and have a reasonable agreement with simulated results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.2034-2036
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• 2004

In this paper, a low noise amplifier (LNA) in receiver of Low Noise Block Down Converter (LNB) for direct broadcasting service (DBS) is implemented by using GaAs HEMT. The LNA is designed for operation between 10.7GHz-12.7GHz. The LNA consists of input, output matching circuits, DC-blocks and RF-chokes. Simulation result of the LNA shows that a noise figure is less than 1.4dB and a gain is greater than 9.2dB in the bandwidth of 10.7 to 12.7GHz with good flatness of 0.1dB.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2000년도 추계공동학술대회논문집
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• pp.711-727
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• 2000

본 논문에서는 레이다 및 EW수신시스템에서 사용하는 SDLA를 5-7㎓(C-Band)의 RF 주파수대에서 설계 구현하였다. 구현한 SDLA의 특성은 -80㏈m-0㏈m의 동작범위를 얻었고, $\pm$1.2㏈이하의 대수오차, 19.2㎷/㏈의 대수기울기, 출력전압 범위는 0-l.53V, 2.0:1 이하의 VSWR, 약2㏈의 잡음지수와 900$\Omega$의 비디오 임피던스를 얻었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.193-194
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• 2007

This paper presents the design of a power amplifier for full-band UWB application systems using a CMOS 0..18um technology. A wideband RLC filter and a multilevel RLC matching scheme are utilized to achieve the wideband input/output matching. Both the cascade and cascode stage are used to increase the gain and to achieve gain flatness. Simulation results show that the designed amplifier provides a power gain greater than 10 dB throughout the UWB full-band(3.1-10.6GHz) and an input P1dB of -1.2dBm at 6.9GHz. It consumes 35.8mW from a 1.8V supply.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(1)
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• pp.451-454
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• 2002

In this paper, a low-noise amplifier is designed and fabricated using the HJFET for the reception of the Ku-band satellite broadcast signals. The optimum input and output reflection coefficients of each amplifier stage are obtained by the trade-off between the stable gain and the noise figure circle. The amplifier performance is simulated and optimized using a microwave CAD software. The designed amplifier is fabricated and tested. Results of the test show a gain of 17.0 dB, a gain flatness of less than $\pm$2.BdB, the noise figure of less than 1.0 dB, and the input and output reflection coefficient of less than -10 dB.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2005년도 하계학술대회
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• pp.443-447
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• 2005

In this paper, a low noise amplifier(LNA) in a receiver of a Low Noise Block Down Converter (LNB) for direct broadcasting service(DBS) is implemented using GaAs HEMT. The 2-stage LNA is designed for the bandwidth of 11.7GHz - 12.2GHz. The result of a simulation of the LNA using Advanced Design System(ADS) shows that the noise figure is less than 1.4dB, the gain is greater than 23dB and the flatness is 1dB in the bandwidth of 11.7 to 12.2GHz.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2318-2320
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• 2005

In this paper, a low noise amplifier(LNA) in a receiver of a Low Noise Block Down Converter (LNB) for direct broadcasting service(DBS) is implemented using GaAs HEMT. The LNA is designed for the bandwidth of 11.7GHz-12.2GHz. The 2stage-LNA consists of a input matching circuit, a output matching circuit, DC-blocks and RF-chokes. The result of a simulation of the LNA using Advanced Design System(ADS) shows the noise figure less than 1.4dB, the gain greater than 23dB and the flatness of 1dB in the bandwidth of 11.7 to 12.2GHz.