During the postwar decades spanning 1946 to 1975, antenna research coalesced into a theory-driven discipline that connected geometry, materials, and measurement to fundamental performance limits. Researchers emphasized mathematical modeling, near-field/far-field transitions, and the early use of modal ideas to structure design and analysis. The era established a systematic approach that bridged theoretical insights with practical engineering challenges. Historical Significance: The foundations laid in this period created a durable framework for understanding size, efficiency, bandwidth, and pattern formation, enabling reliable prediction and optimization of antennas. This groundwork supported the emergence of modern array theory, compact high-gain configurations, and modal-based design methods that shaped later computational techniques.