• Title/Summary/Keyword: 모드 매칭법

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Calculating transmission loss of cylindrical silencers lined with multi-layered poroelastic sound absorbing materials using mode matching method (모드 매칭법을 이용한 다층 다공성 탄성 흠음재가 채워진 원통형 소음기의 음향투과손실 계산)

  • Lee, Jongmoo;Yang, Haesang;Seong, Woojae
    • The Journal of the Acoustical Society of Korea
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    • v.41 no.4
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    • pp.375-388
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    • 2022
  • This paper deals with the process of obtaining sound transmission loss of a cylindrical silencer lined with multi-layered poroelastic sound absorbing materials. The Biot model and the Johnson-Champoux-Allard-Lafarge (JCAL) model were used to deal with waves propagating in multi-layered poroelastic materials. The boundary conditions required for analysis of the silencer were obtained and the numerical process of finding modes was explained. A numerical experiment was conducted on the 2-layered silencer using the modes and the transmission loss converged with the first 12 modes. Finally, the mode matching method proposed in this research was validated by being compared with the results calculated from Finite Element Method (FEM) about different kinds of sound absorbing materials.

The Scattering Performance of a Junction of Rectangular Waveguide to Coaxial Line with Two Skewed Conducting Posts (두 개의 경사진 금속봉을 가진 구형 도파관과 동축 선로의 접합부의 산란 특성)

  • 이상호;신철재
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.4
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    • pp.351-358
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    • 2002
  • To determine a scattering performance of a rectangular waveguide with two skewed conducting posts in approximation by the mode matching method and the generalized scattering method is presented in this paper. We determined the optimized result from effective analysis to select the adequate eigenmode number in mode matching method for the skewed two conducting posts. And we obtained the scattering performance of the junction of the waveguide to coaxial line with two skewed conducting posts by application of above method. By this result, it can be seen that the transmission performance at output port of waveguide to coaxial line is 3 ㏈ at the angle, 50°And we obtained the reflection performance to decrease linearly along the skewed angle at input port.

calculation of the Performance about a Junction of Rectangular Waveguide to Coaxial Line with an Skewed Conducting Post (경사진 금속붕을 가진 구형도파관 동축선로의 접합구조 특성 계산)

  • 이상호;박익모;신철재
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.7
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    • pp.1271-1281
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    • 2000
  • 본 논문에서는 모드 매칭법과 일반 산란계수법을 이용하여 경사진 금속봉이 도파란내에 놓여 있을 때 반사 특성과 투과 특성을 구하였으면, 이 결과를 이용하여 동축선로와 도파관과의 접합에 응용할 수 있도록 최적의 조건을 도출하였다. 여기서 반사특성은 기울기사 클수록 뚜렷아세 개선되어서 최소-40dB까지 감소하였고, 투과특성은 최적의 각도 45$^{\circ}$에서 최대의 특성을 얻을 수 있었다. 또한, 이를 HFSS의 결과와 비교하였을 때 잘일치하는 결과를 얻을 수 있었다.

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Analysis of Scattering Characteristics of the Rectangular Waveguide with a Horizontal Conducting Post using Mode Matching Method and Generalized Scattering Method (모드매칭법과 일반산란계수법을 이용한 수평 금속봉을 갖는 구형 도파관의 산란 특성 해석)

  • 김원기;김상태;신철재
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.7
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    • pp.698-705
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    • 2004
  • In this paper, we present the analysis method for a rectangular waveguide with horizontal conducting post using mode matching method and generalized scattering method. Scattering characteristics of a rectangular waveguide with the horizontal conducting post according to radius and height of the post are simulated by the proposed method. The simulated results by proposed method show good agreement with the measured results and the HFSS's results. Proposed method are easily applied to the design of a waveguide component with horizontal conducting posts.

A Modified Simple Acoustic Analysis of Rectangular Simple Expansion Chamber with Consideration of Higher Order Modes (고차모드를 고려한 사각형 단순 확장관의 간편음향해석법의 개선)

  • 김봉준;정의봉;황상문
    • Journal of KSNVE
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    • v.9 no.2
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    • pp.340-347
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    • 1999
  • The acoustic performance of reactive type single expansion chamber can be calculated theoretically by plane wave theory. But higher order model should be considered to widen the frequency range. Mode matching method has been developed to consider higher order modes, but very complicated algebra should be used. Munjal suggested a numerical collocation method, which can overcome the shortcomings of mode matching method, using the compatibility conditions for acoustic pressure and particle velocity at the junctions of area discontinuities. But the restriction of Munjal's method is that the ratio between the area of inlet(or outlet) pipe and that of chamber must be natural number. In this paper, the new method was suggested to overcome the shortcomings of Munjal's method. The predictions by this method was also compared with those by the finite element method and Munjal's method in order to demonstrate the accuracy of the modified method presented here.

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Analysis of Scattering Characteristics of a Rectangular Waveguide with Conducting Half Cylinders using the Mode Matching Method (모드매칭법을 이용한 금속의 Half Cylinder가 있는 구형 도파관의 산란 특성 해석)

  • 김원기;천동완;김상태;신철재
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.8A
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    • pp.962-971
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    • 2004
  • In this paper, we present the numerical analysis method for analyzing scattering characteristics of a rectangular waveguide with the conducting half cylinder using the mode matching method and compute scattering characteristics of a waveguide according to the rotation and changing radius of the half cylinder. Also, in conjunction with the generalized scattering method, the proposed method can be easily applied to a rectangular waveguide with cascade structure of conducting half cylinders. From the simulated result of a two pole filter, resonance frequency could be controlled by the rotation of half cylinders. The simulated result shows good agreement with the HFSS's result. The proposed structure and analysis method are easily applied to the design of waveguide components with conducting half cylinders.

Propagation Characteristics of Rectangular Waveguide with Elliptical Conducting Post (타원형 금속봉이 있는 구형 도파관의 전파특성)

  • Kim, Won-Ki;Lee, Chang-On;Kim, Sang-Tae;Sul, Yong-Tae
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.4A
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    • pp.256-266
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    • 2003
  • In this paper, scattering characteristics of the rectangular waveguide with elliptical conducting post and equivalent impedance of post are analyzed by mode matching method and generalized scattering method. The scattcring characteristics of rectangular waveguide are varied by the height and eccentricity of elliptical conducting post. When the height of post(2.54mm, 4mm) is small, variation in scattering characteristics appears in total simulated frequency. But as the height of post(7.62mm, 9mm) is increased, it is dominant in higher frequency. The simulated result shows good agreement with the HFSS's result. Proposed structure and analysis method are easily applied to the design and manufacture of waveguide component with elliptical conducting post.

Analysis and Fabrication of Waveguide E-Plane Metal Insert Bandpass Filter for Milli-meter Waves (밀리미터파를 위한 도파관 E-면 금속삽입 대역통과 여파기의 설계 및 제작에 관한 연구)

  • 이용민;박종화;최진일;전형준;나극환
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.1
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    • pp.108-114
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    • 1998
  • This paper presents the design and fabrication of waveguide E-plane metal insert bandpass filter for milli-meter waves which is analyzed transmission characteristics by calculating the generalized scattering matrix using mode-matching method. The bandpass filter was fabricated to verify the proposed method by the WR-34 rectangular waveguide to operate in 30.085 ~ 30.885 GHz. The fabricated waveguide E-plane metal insert band- pass filter was established the fact that it is so adaptive for milli-meter waves due to the measured data closely consistent with the results of analysis using mode-matching method, that is, the maximum value of insertion loss is 0.8 dB and the return loss is below -15 dB.

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ACOUSTIC ANALYSIS OF RECTANGULAR SIMPLE EXPANSION CHAMBER WITH CONSIDERATION OF HIGHER ORDER MODE OF INLET/OUTLET (입.출구의 고차모드를 고려한 사각형 단순확장관의 음향해석)

  • 이정환
    • Journal of Advanced Marine Engineering and Technology
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    • v.23 no.6
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    • pp.748-754
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    • 1999
  • The acoustic performance of reactive type single expansion chamber can be calculated theoretically by plane wave theory. But higher order modes should be considered to widen the frequency range. Munjal has suggested the method for analyzing the acoustic properties of simple expansion chamber with taking into consideration of higher order mode of inlet/outlet. But his method cannot predict the acoustic properties exactly when the dimensions of inlet/outlet and expansion chamber have not integer multiples. In this paper the new method was suggested to overcome the shortcomings of Munjal's method The predictions by this method were also compared with those by the finite element method.

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Optimal Design of Piezoelectric transformer for High Efficiency and High Power density using AWE (AWE를 이용한 고효율 고전력 밀도 압전 변압기의 최적설계)

  • Seo, Jung-Moo;Joo, Hyun-Woo;Jung, Hyun-Kyo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.780-783
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    • 2004
  • 본 논문에서는 유한요소법과 등가회로법을 이용하여 윤곽 진동형 압전변압기의 특성을 해석하고 이를 통해 압전변압기의 매칭 임피던스와 기계 및 전기적 결합계수를 계산하였다. 실험적 결과를 통하여 수치해석의 타당성을 검증한 후, 진화 전략에 기초한 멀티 모드 함수의 최적 알고리즘을 이용하여 고효율 고전압 밀도 압전 변압기의 형상 최적화를 수행하였다. 최적화 과정에서의 계산 시간을 단축시키기 위하여 AWE(Asymptotic Waveform Evaluation)를 적용한 유한요소법을 사용하였다.

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