• Journal of Multimedia Information System
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• 제5권2호
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• pp.143-146
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• 2018

The eigen value problem of a coaxial cavity and a modified pill box cavity is investigated using the mode matching technique. The coaxial cavity has a cylindrical cavity with beam ports and center conductor. The pill box cavity is the same as a coaxial cavity without center conductor. The electric field and magnetic field are formulated in propagation region and resonance region. The boundary and orthogonal conditions are applied to the electric and magnetic fields. We derived the eigen value equation by the proposed procedure in a coaxial cavity and a modified pill box cavity. The electromagnetic field of the real structure is disturbed by the coaxial wire. The effect of the coaxial wire in pill box cavity with beam ports increase the dominant resonant frequency. The coaxial line method of the coupling impedance is not adequate for a cylindrical cavity. The results of the mode matching technique and simulation agree well. The results confirm the proposed formulation is valid.

• 대한기계학회논문집A
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• 제24권5호
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• pp.1314-1322
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• 2000

The acoustic property of reactive type single expansion chamber can be analyzed by traditional plane wave theory. This theory can be applied in low frequency range and has good performance. But this theory can't include higher order modes, therefore another method is essential to analyze acoustic filter in high frequency range. Many researcher suggested the method that can concern higher order modes, and their methods are using mode matching technique. But there is no method that can be applied to the analysis of single expansion chamber with arbitrary inlet/outlet duct position and numbers of higher order modes of inlet/outlet duct and middle chamber. In this paper, the method which can analyze single expansion chamber with arbitrary inlet/outlet duct position and numbers of higher order modes of inlet/outlet duct and middle chamber using fundamental mode matching technique, was suggested and the predictions by this method was compared with those by the finite element method, and the influence of inlet/outlet location to acoustic performance of single expansion chamber is investigated and explained by higher order mode effects.

• 대한전자공학회논문지
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• 제27권12호
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• pp.1810-1816
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• 1990

Step discontinuities of microstrip lines are analyzed using the mode-matching technique based on the well-known waveguide model. Including higher-order modes, the generalized scattering matrices are obtained. Asymmetrical step discontinuities as well as symmetrical step discontinuities are analyzed. The resonance characteristics of microstrip patches are calculated by cascading two microstrip step discontinuities through a uniform microstrip line. Experimental results agree well with theroretical ones.

• 전자공학회논문지D
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• 제34D권10호
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• pp.53-59
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• 1997

In this paper, we present a 20 GHz low-loss dual-mode channel filter designed by using mode matching method. The performance of dual-mode channel filter mainly depends on iris characteristics. Therefore the exact design of iris is the key point to get good frequncy response of the filter. MOde matching technique is widely used ot design several kinds of waveguide filters because it is simple in theory and can easily calculate the scattering matrices at the discontinuities with simple structure like iris coupled filters. Additionally the effect for finite thickness of the iris in the dual-mode cavity iflter is analyzed by te full-wave method, providing the exact filter implementation without trial and error.

• 한국전자파학회논문지
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• 제30권4호
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• pp.270-274
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• 2019

본 논문에서는 모드정합법을 이용하여 평면형 전자파 흡수체의 성능을 분석한다. 제안된 전자파 흡수체는 완전도체와 자성체가 주기구조를 이루고 있으며, 평행 편파 입사파가 인가되는 조건에서 평판의 두께에 따른 투과 및 반사 전력을 계산한다. 제안된 전자파 흡수체의 경우, 특정 구조에서 자성체가 아닌 진공으로 구성된 주기적인 평판 슬릿 또는 자성체 단독으로만 존재하는 경우에 비해 높은 흡수율을 가지는 것을 확인하였다. 전체적인 흡수 및 투과 특성의 수치해석 결과는 상용 시뮬레이터와의 비교를 통해 검증하였다.

• 소음진동
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• 제9권2호
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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.

• 비파괴검사학회지
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• 제24권6호
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• pp.597-602
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• 2004

유도초음파의 현장적응에 있어 전파모드를 규명하는 것은 매우 어렵지만 중요한 과제이다. 본 연구에서는 분산성이 적은 단일모드를 발생시키고 검출할 수 있는 기법에 대해 다루고 있으며, 현장 적용성과 자동화를 위해 비접촉식의 기법을 적용하였다. 모드 선택성을 강화한 비접촉식의 유도초음파 기법으로는 선배열 슬릿을 이용한 레이저빔을 이용하였으며, 에어커플 변환기를 수신자로 사용하였다. 선배열의 레이저 조명은 파장과 일치하여 특정한 모드를 발생시킬 수 있다 또한, 에어커플 변환기는 공기 중으로 누설되는 유도초음파를 수신각도를 조절하여 선택적으로 모드를 수신할 수 있다. 1mm 두께의 알루미늄 판에 덕 기법을 적용한 실험결과로부터 제안하는 기법의 유용성을 검증하였고, 특히 단일한 $a_0$모드의 발생 및 수신에 효과적인 기법으로 나타났다.

• Journal of electromagnetic engineering and science
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• 제1권1호
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• pp.60-62
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• 2001

A novel approach for modeling the thermic endfire interstitial applicator is presented. A hypothetical semi-infinite circular cylinder is added in the endfire direction in order to facilitate the theoretical modeling approach. The Fourier transform and mode-matching technique is utilized to obtain a solution in fast-convergent series Numerical computations for the input impedance are performed to check the Validity of the theoretical model.

• KIEE International Transactions on Electrophysics and Applications
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• 제2C권5호
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• pp.268-272
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• 2002

In this paper, we proposed a procedure to analyze a shielded-microstrip step discontinuity using the mode matching method (MMM) combined with the vector finite element method (VFEM), which is used to find the equivalent waveguide-model for a microstrip. In order to calculate the effective-widths and -dielectric permittivity of the equivalent waveguide-model corresponding shielded-microstrip, the propagation constant and characteristic impedance are calculated from the VFEM. MMM is then applied to find the scattering parameter in the planar waveguide. This technique makes it possible to take advantage of the high accuracy of the VFEM as well as the high efficiency of the MMM.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2006년도 추계 종합학술대회 논문집
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• pp.455-457
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• 2006

전자기파에 대한 경계조건들의 상호 관계와 등가성을 도파관 스텝 관점에서 고찰한다. 본 연구방법의 명확성을 확인하기 위해 구형도파관 스텝의 특성을 경계조건 관점에서 비교한다. 구형도파관 스텝의 특성은 모드정합법을 기준으로 계산한다. 계산의 명확성을 보기 위하여 수렴 특성 계산과 전자장의 분포를 살펴본다.