The authors have used the FDTD method to model and predict the radiation patterns from a microstrip antenna. One problem in modelling microstrip antennas is that these structures are highly resonant. The authors have described techniques to reduce this problem and have also given methods to improve accuracy and to reduce run-times. These methods include sub-gridding around discontinuities and parallel processing. The authors have carried out modelling on three computer systems (an HP400, a 486-based PC and a 386-based PC with a transputer array) and they conclude with their opinion that the 3D FDTD method is an efficient and accurate techniques to model microstrip antennas