The Method of Moments in Electromagnetics

Chapter 2A Brief Review of ElectromagneticsSolving electromagnetic problems requires the application of Maxwell’s Equationswith the appropriate formulation and boundary conditions. In this chapter we presenta review of the electromagnetic theory pertinent to moment method problems. Wewill summarize Maxwell’s Equations and formulations for radiation, and deriveGreen’s functions introduced in those relationships. We will then discuss vectorpotentials, near and far radiated fields, and equivalent problems. We then derivethe surface integral equations of radiation and scattering, which we solve using themoment method in subsequent chapters.2.1 MAXWELL’S EQUATIONSGiven a homogeneous medium with constituent parameters ¯ and , the electric andmagnetic fields must satisfy the frequency-domain Maxwell equationsÖ¢E M H (2.1)Ö¢H J · ¯E (2.2)Ö¡D Õ (2.3)Ö¡B Õ Ñ (2.4)where D ¯E, B H, and the time dependence ÛØ has been assumed andwill be suppressed throughout this text. Though the magnetic current M and chargeÕ Ñ are not physically realizable quantities, they are often employed as mathematicaltools to solve radiation and scattering problems, as discussed in Section 2.6.5