• Journal of the Institute of Electronics Engineers of Korea TE
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• v.42 no.4
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• pp.69-76
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• 2005

In this paper, a 2 stage 6-pole bandpass filter(BPF) is designed and implemented by using triple-mode cavity for satellite payload system. The BPF has a 100MHz bandwidth at the center frequency of 14.5GHz(Ku-band) and the response of the filter is the Chebyshev function. The cavity filter uses two orthogonal $TM_{113}$ modes and one $TM_{012}$ mode. The coupling between the adjacent cavityes(intercavity coupling) results in a Chebyshev response and is accomplished by only H-filed component of If modes. The size and location of intercavity slot is determined by the coupling equation from E-and H-field of TE and TM resonant modes in circular cavity. The 2-stage 6-pole triple-mode cavity BPF has the insertion loss of 2.4dB and the reflection loss of 15dB in the passband. The triple-mode BPF proposed in this thesis can be used as channel filters for satellite payload system and can minimize filter assembly in general wireless communication system.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.65-65
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• 1991

레이저 분광학의 연구에 있어서 고출력이며 좁은 선폭인 레이저광이 요구된다. 특히 고리형 공진기 레이저는 이득물질에서 공간 홀 버닝 효과 (Spatial Hole Burning effect)를 줄이거나 없앨수 있으므로 정상파로 발진하는 레이저에 비하여 높은 출력의 단일모드 발진을 얻을 수 있다. 8자형 고리 공진기 레이저에서 외부 되반사경과 코팅되지않은 에탈론의 조합을 사용하여 높은 출력의 단일모드를 얻었다. 색소분자의 에너지 준위를 2준위 구조로 가정하여 고리형 색소레이저에 있어서의 단일모드 발진의 안정성(Stability)을 살펴보았으며 양방향으로 단일모드 발진을 하는 경우에 있어서의 쌍안정(Bistability) 상태를 확인하였다.

• Journal of Power System Engineering
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• v.10 no.4
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• pp.172-180
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• 2006

본 논문은 Dijkstra 알고리즘에 기초한 최단거리 경로계획을 하며 이 경로를 추적하기 위한 슬라이딩 모드 제어를 제시한다. 슬라이딩 모드 제어기는 동적매개변수 불확실성과 입력외란이 존재 시에도 강인 점근적으로 계획된 경로를 추적하도록 한다. 더불어 작업장 내의 이동로봇의 위치를 USB 카메라에 의해 감지하며, Pin-hole 카메라모델로 하여 카메라에 의해 관측되는 작업장 내의 이륜구동로봇의 위치좌표를 결정하였으며, 이 위치를 정확히 감지하기 위해 Tsai법을 사용하여 카메라 보정한다. 시뮬레이션 결과는 슬라이딩 모드 제어기의 성능을 검증하기 위해 보였다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.224-225
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• 2003

이 연구에서는 광결정 (photonic crystal) 박막 (slab) 위에 제작된 막대형 공진기의 공진모드의 특성을 보고한다. 먼저 3차원 FDTD 방법을 이용하여 각각의 공진 모드들의 모드 형태, 공진주파수, 품위값(Q factor) 등을 구하였다. 광결정 격자의 주기가 $\alpha$ 일 때, 슬랩의 두께는 0.4 $\alpha$ , 구멍의 반지름은 0.35 $\alpha$ 로 하였다. 슬랩의 굴절률 (n) 은 실험에서 사용한 InP의 1.55 $\mu$m 에서의 굴절률 값인 3.4 로 정하였다. (중략)

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.677-684
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• 2004

This paper presents direct T $M_{01}$-T $E_{11}$ small mode converter using circular waveguide with tilted structure for X-band high power system. It is designed to transmit microwave energy from Relativistic Backward-Wave Oscillator(RBWO) source to hem antenna effectively, with optimized geometry a parameter study The simulated and measured results of return loss, fractional power of each mode, impedance bandwidth and mode pattern are provided.d.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1149-1155
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• 1999

This paper presents a narrow-band orthomode transducer(OMT) based on waveguide to waveguide transitions which can separate two linearly polarized orthogonal modes. This operates in the range 120Hz-13GHz frequency band. It consists of two parts, main arm and side arm. Stepped transformers are designed and an inductive post is inserted to improve the characteristics of the transmission loss and isolation. This paper also presents results from fabricated OMT These results show that the transmission loss is less than 1dB and the isolation between the ports for the OMT is above 20dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.1
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• pp.147-156
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• 1998

In this paper, an arithmetic processor using multi-valued logic is designed. For implementing of multi-valued logic circuits, we use current-mode CMOS circuits and design encoder which change binary voltage-mode signals to multi-valued current-mode signals and decoder which change results of arithmetic to binary voltage-mode signals. To reduce the number of partial product we use 4-radix SD number partial product generation algorithm that is an extension of the modified Booth's algorithm. We demonstrate the effectiveness of the proposed arithmetic circuits through SPICE simulation and Hardware emulation using FPGA chip.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.11
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• pp.85-90
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• 1998

A 1 4 polymeric optical power divider based on the multimode interference effect is designed and fabricated. The two dimensional finite difference beam propagation method has been utilized in designing the device. Polymers used for the core layer and the cladding layer are Cyclotene-3022 and UV-15, respectively. The device is fabricated by the reactive ion etching method. The splitting ratio of the fabricated device is 0.93 : 1.00 : 0.93 : 0.90 for TE mode and 0.84 : 0.94 : 1.00 : 0.83 for TM mode. The advantages of this device are small size and low polarization-dependence.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.194-197
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• 2005

Pulse-mode performance evaluation is made for a set of monopropellant hydrazine thrusters producing $0.95 lb_{f}$ of nominal steady-state thrust at an inlet pressure of 350 psia. With a brief description on the hot-firing test matrix, a typical data obtained from pulse-mode firing is given directly showing the variational behavior of propellant supply pressure, vacuum condition, and thrust, in addition to the thermal response of the thruster. The performance features are successfully compared to the reference criteria of 1-lbf standard monopropellant rocket engine.

• Korean Journal of Optics and Photonics
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• v.15 no.1
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• pp.22-27
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• 2004

In this paper, we designed a mode size converter to reduce coupling loss between optical waveguide and single mode fiber. The proposed mode converter is composed of periodically segmented tapered waveguide to achieve small size and easy fabrication. For the optimally designed mode size converter at 1550nm, the taper length is 500(equation omitted), the segmentation period 5ß:, the waveguide width of fiber contact section 1.3ß:, and duty cycle 0.95. The coupling loss of the optimized mode size converter is 0.33㏈/point, which is 1.27㏈/point lower than that without the mode size converter.