AS/NZS IEC 61000.4.20:2023 adopts and modifies IEC 61000 4 20:2022, which focuses on emission and immunity test methods for electrical and electronic equipment using various types of transverse electromagnetic (TEM) waveguides. These types include open structures (e.g. striplines and electromagnetic pulse simulators) and closed structures (e.g. TEM cells). These structures can be further classified as one-port, two-port or multi-port TEM waveguides.