• 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).

• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 제15회 정기총회 및 동계학술발표회
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• pp.272-273
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• 2004

Optical connector is prone to take environment attack since it is exposed to various environmental conditions. As the data bit rate is increased in the modern optical communication system. the stability of optical connector becomes more important issue in complex network comprising of many connection by connectors. In this research, to estimate the influence of defects of connector, especially surface scratches, on the transmission, surface scratches were intentionally introduced on the cross sectional surface of optical connector and the insertion loss, return loss. and BER were measured as functions of geometry and density of scratches, Environmental conditioning was also performed onto these connectors and the variations of basic optical characteristics mentioned above were measured. Based on this measurement the lifetime of connectors was estimated by statistical prediction method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.408-409
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• 2008

In this paper the power divider is realized using the IPD processes for 900/1800 MHz; the designed power divider achieved the isolation of more than -24 dB. the insertion loss of nearly -3.5 dB, and the return loss of about -25 dB. The simple dual-band power divider based on SI-GaAs substrate is realized within the die size of about $2.5\times2mm^2$.

• Journal of electromagnetic engineering and science
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• 제8권1호
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• pp.12-16
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• 2008

In this paper, we introduce a coupling, which is achieved through the aperture instead of the conventional edge coupling, so that the bandpass filter is reduced less than half in size compared to conventional planar type. The resulting filter configuration has a near two-fold symmetry, where the aperture coupling is used in the middle of the coupling stages. We designed a bandpass filter using two tapped hairpin resonators, of which the order becomes four. The designed bandpass filter has the size of $8.9{\times}18.3\;mm$. It has the return loss better than 17dB and the insertion loss of less than 5 dB in overall passband. The measured results show good agreements with simulated ones.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1502-1503
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• 2007

In this paper, inductive coupled LC balun has been desi gned and simulated for embedding into an organic packaging substrate. Inductive coupling method was applied to obtain wide band characteristics, and high dielectric film was utilized to reduce a size of the balun. The proposed balun has a novel scheme which consists of three embedded LC resonators with inductive coupling. This proposed balun has relatively small inductance and capacitance values which can be easily embedded into the organic packaging substrate. Furthermore, it has a good phase imbalance characteristic. The simulated results of proposed balun are an insertion loss of 1.2 dB, a return loss of 10 dB, a phase imbalance of 1 degree at frequency bandwidth of 750 MHz ranged from 1.8 GHz to 2.55 GHz, respectively. This balun has an area of $2mm{\tims}3.5mm{\times}0.66mm$ (height).

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.401-404
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• 2002

This paper proposes a new symmetrical bandpass filter based on capacitive loading with a coplanar waveguide (CPW) structure. The filter was numerically designed at the operating frequency around 2 ㎓ by using IE3D software package. The characteristics of the proposed filter were then measured which the results were in good agreement with simulation. The passband insertion loss was considerably low (~3 ㏈) and the return loss was high (greater than 10 ㏈). The size of the proposed filter was also decreased approximately 50% when comparing with the fitters using conventional transmission lines.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1637-1639
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• 2000

Resister networks are used widely in many, high frequency applications for attenuators. In this paper we studied the frequency characteristics of attenuator using network analyzer and compared Ni-Cr thin film resistor with thick film resistor attenuator. Also from return loss, insertion loss and VSWR we obtained the maximum available frequency of these attenuators.

• 대한전자공학회논문지TC
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• 제39권3호
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• pp.158-164
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• 2002

2-6 GHz 디지털 위상변위기 모듈을 설계, 제작하였다. 위상변위기 모듈에 사용된 MMIC 칩은 광대역을 구현하기 위해 Lange 커플러로 구성된 반사형 회로를 이용하여 설계 및 제작하였다. 위상변위기 모듈은 6.1°RMS 위상오차, 13.5 dB 최대 삽입손실과 각각, 8 dB와 10 dB의 입·출력 반사손실 특성을 갖는다. 32개의 위상 상태를 측정하기 위해서 컴퓨터를 사용하여 측정을 자동화 시켰다. 8×8 위상배열용 모듈들간의 RMS 삽입 위상오차는 최대 ±0.5°이내이고, 모듈들간의 평균 삽입손실 편차는 최대 ±0.5 dB를 넘지 않았다. 제작된 위상변위기 모듈의 크기는 45 × 22.5 × 60 ㎣. 이다.

• 대한전자공학회논문지TC
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• 제48권9호
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• pp.47-53
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• 2011

본 논문에서는 커넥터의 특성임피던스 추출, 분석 방법 및 설계 변경 방법을 제안하고 임피던스를 정합하여 신호 전달 특성을 개선한다. 3차원 FEM(Finite Element Method) 전자기장(Electro-Magnetic Field) 시뮬레이터를 이용하여 커넥터의 S-파라미터를 계산하고 반사손실 및 삽입손실을 추출한다. 커넥터의 신호 전달 특성은 반사손실이 0.9 GHz 이후부터 -20 dB 이상의 값으로 높게 나타났다. 신호 전달 특성이 낮은 원인을 파악하기 위해서 회로 해석 시뮬레이터를 이용하여 커넥터의 등가 회로 모델을 추출하고 특성임피던스를 계산하였다. 커넥터의 특성임피던스는 $90.3{\Omega}$으로 임피던스 부정합이 발생하여 신호 전달 특성이 저하되었다. 따라서 신호 전달 특성을 개선할 목적으로 임피던스를 정합하기 위해서 커넥터의 커패시턴스를 증가시켰다. 이러한 설계 방안으로 커넥터 신호선의 유효 면적을 확장하고, 커넥터의 몸체 소재로 고유전체를 사용하였다. 설계 변경된 커넥터의 특성임피던스는 $58.6{\Omega}$으로 임피던스 정합에 보다 근접하여 커넥터의 반사손실이 대략 10 dB 향상되었다. 신호선의 유효 면적 증가에 의한 반사손실 개선과 고유전체의 적용으로 전자기파의 신호선 주변 집중에 의해서 삽입손실 또한 개선되었다.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.107-111
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• 1999

A high-temperature superconducting 1.78 GHz bandpass filter, designed for PCS applications, is presented. The structure consists of microstrip pseudo-lumped elements, which make the miniaturization of the filter possible. A 5-pole microstrip filter can be realized on 37 mm ${\times}$ 9 mm LaAlO$_3$ substrate, using double-sided high-temperature superconducting YBa$_2Cu_3O_{7-{\delta}}$ thin film. This filter shows 0.7% fractional bandwidth, 0.3 dB insertion loss, and 12 dB return loss in the passband at 60 K.