The convergence property of the method of Moment for Dipole antenna using new segmentation. # Saki Arahata, Toru Uno, Takuji Arima Electrical and Electronic Engineering, Tokyo Univ. Agr. & Tech. # 50012645203@st.tuat.ac.jp 1. Introduction In recent years, mobile communication equipment including smartphones are widely used. In these equipment, an antenna is important devices to communicate with base stations. In order to develop high-performance antenna, numerical analysis is important. The Method of Moment[1] (MoM) is one of the antenna analysis methods. In the MoM analysis, currents of the antenna are divided by segments. The MoM gives us a beneficial result in antenna analysis for dipole antenna. However, calculated input impedance of the antenna by MoM does not converge by increment segments. In order to improve convergence property by segmentation method in Galerkin-Moment method using piecewise sine function as expansion function. New segmentation methods had been proposed[2,3]. In ref.[3], a new segmentation which uses root of Chebyshev polynomial. In this segmentation method, division point to make segment is defined by using root of Chebyshev polynomial has been proposed. The result shows good convergence in half-wave dipole antenna analysis. In this study, the segmentation method is applied to several antenna lengths and several length of feeding gap. Moreover, the reason of improvement is discussed. 2. Method of Moment Figure 1: analysis model In this section, the Method of Moment is explained briefly. In this paper, a dipole antenna with radius r, length 2h, and feeding gap size d is analyzed. As shown in figure 1, the antenna is divided by N segments, in order to analysis by MoM. Current on the surface of the antenna is approximated by expression (1) as ) (r' f J J ) J(r' n n n I , n N 1 n = ∑ ≈ = (1) where is current on segment n, I n is coefficient to be determined. I n is called as expansion coefficient. f n is function. Using scattering electric field equation as POS1-41 Proceedings of ISAP2012, Nagoya, Japan 652