Six Easy Steps That Explain the Radiation of the Rectangular Patch Antenna [Education Corner]

This article revisits a classic in antenna theory: the rectangular patch antenna (RPA). The radiated electric field is computed from its physical sources, i.e., the conduction and polarization currents, whose contributions are clearly identified. The symmetrical equivalent of the antenna is first analyzed, and a coordinate system is chosen with the z-axis parallel to the conduction currents. The radiation of these currents appears as close to that of two parallel dipoles carrying opposite currents, which means a very simple and easy-to-understand system. It is further shown that the effect of the polarization currents is typically much smaller. The analysis is fully self-sufficient (no reference specific to the subject is needed). The radiation is summarized by a figure with six parts that graphically explains the topic step by step.