2017/05/22 by Kurt Schab, Schab, Kurt, Lukáš Jelínek +11
Engineering · Physics and Astronomy · #Antenna Design and Optimization #Classical Physics (physics.class-ph) #Electromagnetic Compatibility and Measurements #Electromagnetic Scattering and Analysis #FOS: Physical sciences
paper · pdf · doi:10.48550/arxiv.1705.07942
openalex publication_date 2017/05/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Though commonly used to calculate Q-factor and fractional bandwidth, the energy stored by radiating systems (antennas) is a subtle and challenging concept that has perplexed researchers for over half a century. Here, the obstacles in defining and calculating stored energy in general electromagnetic systems are presented from first principles as well as using demonstrative examples from electrostatics, circuits, and radiating systems. Along the way, the concept of unobservable energy is introduced to formalize such challenges. Existing methods of defining stored energy in radiating systems are then reviewed in a framework based on technical commonalities rather than chronological order. Equivalences between some methods under common assumptions are highlighted, along with the strengths, weaknesses, and unique applications of certain techniques. Numerical examples are provided to compare the relative margin between methods on several radiating structures.