• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.4
• /
• pp.391-396
• /
• 2008

In this paper, we proposed the new rectangular waveguide-NRD waveguide transition in which the transition function about the standard waveguide is built in within the NRD waveguide ifself. The newly proposed rectangular waveguide-NRD waveguide transition was realized use of NRD waveguide input/output side wall thickness and hole width. In the case of the wall thickness, it was nearly identical with the half of the NRD waveguide guide wavelength and the width of an hole was nearly coincide with the length of the long side of the standard waveguide connected with the NRD waveguide. This kind of the principles is applicable to be unrelated with the frequency band. In this paper, it made in 38 GHz band with the rectangular waveguide-NRD waveguide transition and the feasibility was confirmed. In the back-to-back structure, the rectangular waveguide-NRD waveguide transition manufactured in 38 GHz band has the insertion loss less than 0.4 dB and also has the return loss less than 20 dB.

• Journal of Energy Engineering
• /
• v.25 no.1
• /
• pp.86-91
• /
• 2016

Convenient design guideline for Waveguide-below-cutoff (WBC) array is proposed to obtain the minimum waveguide length for electromagnetic pulse (EMP) shielding. The analysis includes circular, rectangular, and hexagonal WBC, determine the total length of the waveguide. When the unit side of rectangular WBC and the diagonal line of hexagonal WBC are given as 30 mm, the length of hexagonal WBC is 5 mm shorter than rectangular case with shielding effectiveness (SE) 80 dB. The length difference is deepened with SE of 100 dB, which shows approximately 30 mm shorter length for hexagonal case than others. In addition, hexagonal WBC requires much shorter length than circular WBC. In conclusion, hexagonal case is the most effective with respect to flow velocity and pressure loss for equivalent SE.

• The Journal of the Acoustical Society of Korea
• /
• v.22 no.7
• /
• pp.545-553
• /
• 2003

This paper is concerned with protecting piezoelectric transducers used in an ultrasonic flowmeter from the high temperature of hot fluid in a pipe by using a waveguide and with improving the propagation of ultrasonic longitudinal vibration in the waveguide. Waveguide material has been chosen for efficient insulation of heat transferred in the waveguide, and the minimum length of the waveguide for protecting piezoelectric transducer has been estimated. Forced response of the longitudinal vibration in a uniform circular rod has been obtained and the length of the waveguide has been selected for maximum amplitude. Longitudinal vibration response of a conically-tapered rod excited at a natural frequency has been obtained to confirm that wave motion is amplified as the cross-sectional size of the waveguide decreases along the axial direction. The fact that dispersion of a pulse wave in a waveguide is reduced as the cross-sectional radius is decreased has been examined theoretically and confirmed experimentally by using a single-rod waveguide. A bundle-type waveguide has proven to be a practical one through the evaluation of the wave propagation performance.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.19 no.1
• /
• pp.19-24
• /
• 2024

In this paper, in order to realize lower cut-off frequency of the waveguide, the folded Ridge waveguide (FRWG) is suggested by alternating T-shape structure in the conventional folded waveguide with Y-shape structure. Suggested FRWG can be equivalent by the reverse Ridge waveguide. As the height of side of the FRWG is lower, the width of side is increased. Therefore, the cut-off frequency of the FRWG can be decreased more than half compared with conventional waveguide. The FRWG is designed with the length, height, and width of Y-shape structure of 40mm, 20mm, and 2mm, respectively. Designed FRWG has the cut-off frequency of the 1.996GHz. Also, the transition between the FRWG and SMA connector is designed. The transition is optimized by the capacitance of the signal line of the connector. Its result shows the VSWR under 2:1 in the band of 2.064 ~ 3.050 GHz. Suggested FRWG can be applied with miniaturization of various waveguide devices.

• The Journal of the Acoustical Society of Korea
• /
• v.29 no.7
• /
• pp.448-457
• /
• 2010

Vibrations and wave propagations in waveguide structures can be analysed efficiently by using waveguide finite element (WFE) method. The WFE method only models the 2-dimensional cross-section of the waveguide with finite elements so that the size of the model and computing time are much less than those of the 3-dimensional FE models. For cylindrical shells or pipes which have simple cross-sections, the external coupling with fluids can be treated theoretically. For waveguides of complex cross-sectional geometries, however, numerical methods are required to deal with external fluids. In this numerical approach, the external fluid is modelled by the boundary elements (BEs) and connected to WFEs. In order to validate this WFE/BE method, a pipe submerged in water is considered in this study. The dispersion diagrams and point mobilities of the pipe simulated are compared to those that theoretically obtained. Also the acoustic powers radiated from the pipe are predicted and compared in both cases of air and water as an external medium.

• Journal of the Korean Vacuum Society
• /
• v.4 no.2
• /
• pp.124-134
• /
• 1995

포항가속기연구소에서는 PLS 2-GeV 선형가속기 클라이스트론의 교체 및 보수시에 사용하기 위하여, 80 MW급 S-band의 도파관 밸브를 개발중에 있다. PLS형 도파관 밸브는 결합수단 없이 대전력을 전송할 수 있는 구조로 설계되어, 전력전송에 대한 제한을 받지 않는 특징을 갖는다. 본 도파관 밸브의 주요구성부는 밀착구동체를 갖는 U자형 도파관부, 두 개의 H-코너가 부착된 진공함, 그리고 두 개의 Viton O-링이 장착된 진공기밀판으로 이루어져 있다. 시제품용 도파관 밸브의 특성조사 결과, 펄스폭 3.5 $\mu$sec, 반복율 30 Hz에서 65MW의 전력전송을 얻을 수 있었다. 본 논문에서는 PLS도파관 밸브의 설계 개념, 기계적 특성 및 가공의 순으로 자세히 논할 것이며, 또한 현재까지의 실험결과 및 앞으로의 계획에 대하여 보고하기로 한다.

• Proceedings of the IEEK Conference
• /
• 1998.06a
• /
• pp.181-184
• /
• 1998

본 연구에서는 단층구조 평면형 슬롯 도파관 배열 안테나에 있어서 전력분배기로 이용되는 유도성 포스트가 있는 도파관 π-결합의 특성과 각 포트로 나누어지는 전력의 주파수 특성을 고찰하였다. π-결합은 한 개의 결합창을 통해서 두 개의 도파관으로 전력을 분배하여 결합된 도파관들을 동위상·동진폭으로 급전시킬 수 있다. 전력분배 특성은 Galerkin법을 사용해서 해석했고 유도성 포스트를 붙임으로써 π-결합으로부터의 반사는 -27dB이하로 억제할 수 있음을 확인하였다.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
• /
• 2005.05a
• /
• pp.111-115
• /
• 2005

광 도파관 제작을 위한 마스터를 (100), (110) 실리콘 웨이퍼를 이용하여 제작하였다. DRIE와 화학적 습식 식각을 이용하여 사각형 모양의 부드러운 표면을 가진 마스터를 구현하였다. 식각된 패턴의 거칠기는 광 도파관을 제작할 수 있을 정도로 충분히 작았다. 마스터와 광 도파관의 분리를 용이하게 하기 위하여 마스터에 산화막을 형성하고 PFAS를 도포함으로써 HIBRIMERs 광 도파관을 성공적으로 제작할 수 있었다.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2001.11a
• /
• pp.169-171
• /
• 2001

본 논문에서는 유한요소법에 기초한 상용프로그램을 이용하여 도파관 필터를 시뮬레이션을 할 경우 도체에 의한 손실을 포함시키는 방법을 제시하였다. 우선 균일한 도파관의 도체에 의한 감쇠의 시뮬레이션 결과를 이론치와 비교하였다. 다음으로 도파관 대역통과 필터의 통과대역 감쇠의 측정결과와 시뮬레이션의 결과를 비교하여 시뮬레이션의 정확도를 검증하였다.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1995.06a
• /
• pp.632-635
• /
• 1995