Development of surface integral equation solutions using the method of moments

Summary form only given. Very simple electrostatic problems were being formulated as integral equations and solved using digital computers beginning in the early `60´s. By the next decade, researchers were solving wire, cylinder, and body-of-revolution problems in both frequency- and time-domain using many of the now-familiar integral equation formulations. But it was Harrington´s 1968 monograph on the Method of Moments (MoM) that generalized, systematized, introduced the terminology, and popularized the projection-based approach. Though the monograph convincingly established MoM´s variational character and its applicability to linear operator equations of all types, the combination of its emphasis on the projection method and its immediate application to a variety of scattering and antenna problems led to its becoming almost exclusively associated with integral equation applications. Meanwhile, the finite element method (FEM) developed almost independently, driven largely by the microwave circuits and guided wave communities, and became firmly associated with differential equation formulations based on variational principles. Though the overlapping applicability of MoM, FEM, and related methods are now widely recognized, many of the original associations persist today.