Abstract: Near-zone to far-zone transformation in the finite-difference time-domain (FDTD) method can be performed by the integral of the equivalent electric and magnetic currents originated from scattered electric and magnetic fields on a surface enclosing the object. There are two kinds of near-zone to far-zone transformation, one is in the frequency domain and the other is in time-domain. Because the integral for time is included in the 2-D time domain Green function, the calculation of 2-D far-zone time-domain fields is more difficult than that of 3-D far-zone time-domain fields. However, by quantifying the positions of equivalent sources and arranging the time series, the calculations of the time integrals of equivalent sources are converted in to the calculation of matrix multiplying. Besides, by using the analytic method, the abnormal integral for the time is obtained accurately.

Key words: 2-D time-domain Green function, finite-difference time-domain, position quantifying, abnormal integral