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안병철 충북대학교 컴퓨터정보통신 연구소 2001 컴퓨터정보통신연구 Vol.9 No.2
본 논문에서는 도파관 편파기에 흔안테나, 다이플히서 등 주변 부품이 연결될 경우 부품간의 유한한 반사계수에 의한 특성변화를 해석하였다. 편파기, 흔안테나, 다이플렉서의 특성을 산란행렬로 표현한 후 이로부터 이들이 순차적으로 연결될 정우 산란계수를 구하었다. 이로부터 부품간의 유한한 반사에 의한 편파기의 축비 변화를 계산하였다. 전형적인 반사계수 값을 사용하여 축비 변화의 실제적인 갈을 제시하였다. In this Paper we Present an anlaysis of the Performance degradation due to inter-component reflections of the waveguide polarizer connected to a horn antenna and to a diplexer. polarizer. horn antenna, and diplexer are represented by individual scattering coefficients, from which the change of the polariEer axial ratio is calculated. Realistic values of the axial ratio chance are presented for typical reflection valses.
구형 마이크로스트립 안테나 해석을 위한 전송선 모델의 정확도
배재균,안병철 충북대학교 컴퓨터 정보통신 연구소 1999 컴퓨터정보통신연구 Vol.7 No.1
전송선 모델은 구형 마이크로스트립 안테나의 특성을 계산하는데 매우 편리한 방법이며 이를 사용하여 고가의 소프트웨어 없이 간단한 계산에 의해 마이크로스트립 안테나를 설계할 수 있다. 본 논문에서는 다양한 파라미터값에 대해 전송선 모델의 정확도를 검증함으로써 전송선 모델의 유용성을 확인하였다. 구형 마이크로스트립 안테나의 공진 주파수 및 공진 저항을 전송선 모델로 계산한 후 상용 소프트웨어에 의한 해석결과와 실험에 의한 측정값과 비교하였다. 본 논문에서 검토된 전송선 모델에 의한 계산결과는 대부분의 경우에 대해서 상용 소프트웨어에 의한 결과와 약 1% 미만의 공진 주파수 오차를 나타내었다. The transmission line model (TLM) is very convenient method for the calculation of rectangular microstrip antenna characteristics. Using this method, one can design microstrip patch antennas with simple calculations only. This paper describes the usefulness of transmission line model by proving the accuracy of transmission line model for various parameter values of the microstrip patch. resonant frequency and resonant resistance of the rectangular microstrip antenna calculated using TLM are compared to the results by commercial software and by experiments. It is found that the TLM predicts the resonant frequency of a rectangular microstrip patch with accuracy better than 1% in most cases.
Ahn, Bierng Chearl 충북대학교 산업과학기술연구소 1998 산업과학기술연구 논문집 Vol.12 No.2
Simple and accurate analysis formulas for microstrip lines are often useful in preliminary design stages of complicated planar circuits. For microstrip lines with thin conductor thickness, the accuracy of formulas for the characteristic impedance and effective permittivity is well established. In the case of microstrip lines with thick mentalization, the accuracy of same formulas has not been fully studied. In this paper, the accuracy of three most widely used formulas for open microstrip lines with finite conductor thickness is studied by comparison to rigorous two-dimensional finite element calculations.
( Bierng-chearl Ahn ) 충북대학교 산업과학기술연구소 2019 산업과학기술연구 논문집 Vol.33 No.1
In this paper, the image method formulation is presented for the capacitance of two non-contacting metallic spheres. First, a point source in the presence of a grounded conducting sphere is analyzed and equations for the image source are derived. Next, the image theory of a spherical conductor is applied to solve the problem of two non-contacting metallic spheres where one sphere is held at potential V0 and the other at zero potential and vice versa. The two metallic spheres are represented by an equivalent problem with an infinite sequence of image charges inside each spherical conductor, from which the total charge on each sphere is obtained using the Gauss theorem. The capacitance coefficients are obtained from the total charge and potential on each sphere. The mutual capacitance or simply the capacitance between two spheres is obtained from the capacitance coefficients. The potential, electric field, and force on the sphere are calculated using image charges.
Integration of 1/(x<sup>n</sup>+a) over the Real Line
( Bierng- Chearl Ahn ) 충북대학교 산업과학기술연구소 2016 산업과학기술연구 논문집 Vol.30 No.2
The integration of a function over a real line or over the interval [-∞,∞] has many scientific and engineering applications. Formulas of the integral of 1/(x<sup>n</sup>+a) over the real line are derived from the theory of the complex contour integration. Formulas of the definite integral of the function 1/(z<sup>n</sup>+a) are available in open literature like a book by Gradshteyen and Ryzhik, but they are too complicated to apply to the evaluation of the integral over the interval [-∞,∞]. Formulas given in this paper are compact and easy to use. They can also be used in the course of engineering mathematics.
Three-dimensional green's function in the rectangular waveguide
Ahn, Bierng-Chearl 충북대학교 컴퓨터정보통신 연구소 2004 컴퓨터정보통신연구 Vol.11 No.3
The three-dimensional Green's function is presented for use in the numerical solution of arbitrary structures in a rectangular waveguide. The Green's function is represented in terms of magnetic and electric vector potential functions. Methods for the efficient computation of double series arising in the Green's function are presented.