This chapter presents a general conceptual model and types of EMI emissions, such as radiated and conducted EMI emissions. The EMI model includes three main components: EMI source (emitter), EMI coupling path, and EMI receptor. Associated with these EMI model components, a global strategy for EMI control in radio systems is built. Additionally, this chapter provides a description and comparison between differential-mode (DM) and common-mode (CM) EMI emissions, including the mechanism of their conversion modes. This comparison is illustrated by numerical examples. Additionally, this chapter provides a description and numerical examples of EMI near-field coupling (inductive and capacitive), which is a typical case between two adjacent and parallel unshielded linear (wire) conductors.