In this paper ,the characteristics of one kind of portable handset antenna are analyzed by Moment method. Based on the Pocklington equation and Galerkin method, the current distribution and the input impedance of the monopole antenna and the conducting handset chassis are calculated by using piecewise function as the expansion and testing functions. In addition, the characteristics of the monopoles on different dimensions of conducting handset chassis are analysed. The results indicate that the dimension of...