• Proceedings of the Optical Society of Korea Conference
• /
• 2003.07a
• /
• pp.208-209
• /
• 2003

고밀도 광집적회로의 광도파로는 단일모드 광섬유와 굴절률의 차이 및 코어 크기에 의해 모드 부정합 문제가 존재한다. 본 논문은 이러한 모드 부정합 문제를 해결할 수 있는 모드 크기 변환기를 설계 하고 3-D Beam Propagation Method (BPM)을 이용하여 분석하였다. 모드 크기 변환기술에는 마이크로 렌즈, 테이퍼 광섬유, 렌즈화 광섬유가 사용되고 있으나 이는 패키징 가격이 높으며 광섬유와의 정렬 문제가 존재하므로, 집적된 실리콘 기판위에 제작하는 모드 크기 변환기에 대한 연구가 다각도에서 시도되고 있다. (중략)

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.4
• /
• pp.185-190
• /
• 2015

In this paper we characterized and designed the waveguide antipodal finline transition at 57-65GHz frequency band in V-band for 5G mobile communication systems. Especially, we proposed the design method of spline taper for finline tapers by means of increasing curvature from linear taper. We could perform optimization more effectively by excluding improper regions for optimal performance from optimization using the method. Return losses and insertion losses of antipodal finline transitions were mainly affected by the taper shape of the finline. The resonances in the structure of the finline transition were the strongest enemies who deteriorate the performance of the transition. And we alleviated the resonances using semicircle shaped patch. The designed antipodal finline transition showed good performance as it showed less than -24.2dB of return loss and -0.24dB of insertion loss in the band(57-65GHz) which we suppose to use.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.20 no.5
• /
• pp.151-156
• /
• 2020

To analyze the diffraction properties of optical signals and the significant impacts of tapered sidewall profile at periodic trapezoidal 2D diffraction gratings, Toeplitz dielectric tensor is first defined and formulated by 2D spatial Fourier expansions associated with trapezoidal profile. The characteristic modes in each layer is then based on eigenvalue problem, and the complete solution is found rigorously in terms of modal transmission-line theory (MTLT) to address the pertinent boundary-value problems. Based on those one, the numerical analysis is performed on how the tapered side profile of grating structures with trapezoidal refractive index distribution affects the design of a sub-wavelength grating reflector. The numerical results reveal that this tapered sidewall profile plays a critical role in determining the reflection bandwidth, the average reflectance, and the band edge.

• Journal of the Korean Geotechnical Society
• /
• v.23 no.4
• /
• pp.59-68
• /
• 2007

In this study, evaluation of load capacity and CPT-load capacity parameters were performed using calibration chamber tests for different types of piles including straight-side and tapered piles. Various soil conditions were considered in the investigation, aiming at establishing design procedure for foundation of electronic transmission tower structures. Test results show that no significant difference of total load capacity from straight-side and tapered piles, while individual components of base and shaft load capacities were quite different. Based on the test results, values of CPT-load capacity correlation parameters for different pile types were analyzed for the evaluation of both base and shaft load capacities.

• Journal of the Korean Society for Precision Engineering
• /
• v.32 no.12
• /
• pp.1011-1016
• /
• 2015

In a roll-to-roll continuous system, winding is one of the most important processes since it determines the quality of the final manufactured products such as flexible film and printed electronic devices. Since an adequate winding tension can reduce the incidence of the defects that are derived from the inner stress of the wound roll such as starring and telescoping, it is necessary to determine the optimal taper-tension profile. In this study, an algorithm for the setting of an optimal taper-tension profile in consideration of the residual stress in the wound roll is suggested; furthermore, the algorithm was adjusted for the determination of an optimal taper-tension profile regarding the winding process of $10{\mu}m$ polypropylene (PP) film. As a result of the algorithm-generated, optimal taper-tension profile, the residual stress and radial stress in a PP wound roll were decreased to 27.37 % and 40.05 % (mean value), respectively.

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

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.7 no.3
• /
• pp.246-253
• /
• 1996

In this paper, a problem that occurred in the telegraphist equation established by mode conversion method is solved as analysis tapered transmission line is applied to a waveguide taper. After comparing and analyzing the taper function with variant properties, we select on of taper functions not only that is easily designed but also that have good properties. And then we propose the applicant method to design the waveguide taper and deal with the design of mode transducer between rectangular waveguide and circular waveguide. The measured results of scattering coefficients for the mode transducer fabricated with designed data are agreed well with the theoretical results and the validity of the proposed design and analysis method has been confirmed.

• Journal of Korean Association for Spatial Structures
• /
• v.5 no.4 s.18
• /
• pp.101-108
• /
• 2005

The investigations for mitigating wind-induced excitations of tall buildings have been carried out. The aerodynamic modification of a building shape changing the cross-section with height through tapering, which alters the flow pattern around the building, could reduce wind induced excitations of tall buildings. The fart that a tapered tall building might spread the vortex-shedding over a broad range of frequencies makes more effective for reducing acrosswind responses has been established. In this paper, to investigate the tapering effect for reducing wind-induced responses of a tapered tall building, high-frequency force-balance test was conducted. The six types of building models which have different taper ratio of 2.5%, 5%, 7.5%, 10%, 15% and one basic building model of a square cross-section were tested under the two typical boundary layers representing suburban and urban flow environment. The effect of wind direction was also considered.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.41 no.12
• /
• pp.43-49
• /
• 2004

In this paper, we have designed a mode size converter to reduce coupling loss between super-high delta silica optical waveguides and single mode fibers. The new mode size converter has three design aspects; periodically segmented taper waveguide for minimal size, lateral taper waveguide for simple fabrication, and surrounding trenches to improve coupling loss. In the optimal mode size converter design, coupling loss is 0.33dB/point without trenches and 0.2dB/point with trenches.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.3
• /
• pp.590-595
• /
• 2008

A new adaptive TMS variable area flow meter that is used to the environment measuring equipment is proposed. This system is consist of a ball moving within the tube line which corresponds to gas flow and photo sensor array which monitoring the movement of ball. This system can monitoring the position of bali in case of the very few gas flow in various levels. And it can automatically adjust the gas flow at the highest and the lowest level to prevent the tube line blockage.