Electromagnetic-Power-Based Modal Classification, Modal Expansion, and Modal Decomposition for Perfect Electric Conductors

Abstract

Traditionally, all working modes of a perfect electric conductor are classified into capacitive modes, resonant modes, and inductive modes, and the resonant modes are further classified into internal resonant modes and external resonant modes. In this paper, the capacitive modes are further classified into intrinsically capacitive modes and nonintrinsically capacitive modes; the resonant modes are alternatively classified into intrinsically resonant modes, which are further classified into nonradiative intrinsically resonant modes and radiative intrinsically resonant modes, and nonintrinsically resonant modes; the inductive modes are further classified into intrinsically inductive modes and nonintrinsically inductive modes. Based on the modal expansion corresponding to these new modal classifications, an alternative modal decomposition method is proposed. In addition, it is also proved that all intrinsically resonant modes and all nonradiative intrinsically resonant modes constitute linear spaces, respectively, but other kinds of resonant modes cannot constitute linear spaces; by including the mode 0 into the intrinsically capacitive mode set and the intrinsically inductive mode set, these two modal sets become linear spaces, respectively, but other kinds of capacitive modes and inductive modes cannot constitute linear spaces.

Partial-Structure-Oriented Work-Energy Theorem Based Characteristic Mode Theory for Yagi-Uda Array Antennas

“…In addition, it had been proved in [55,Sec. 3.4.1] and [61] that the local minimum of the curve shown in Fig. 14(b) is corresponding to the internally resonant mode, which oscillates back and forth inside the metallic spherical cavity and doesn't radiate any EM energy.…”

“…In fact, besides the CV of various scatterers, the physical meaning of the CVs of metallic, material, and composite Yagi-Uda antennas can also not be uniformly interpreted by Poynting's theorem. Taking metallic Yagi-Uda antenna as an example, we propose an alternative physical interpretation for CV by using the concept of driving power and the viewpoint of modal decomposition [61] introduced under WET framework, and the interpretation can be easily generalized from metallic Yagi-Uda antenna to material and composite Yagi-Uda antennas, because the driving power and modal decomposition are universally applicable to the various Yagi-Uda antennas.…”

“…To confirm the above qualitative physical picture for the axially-two-directional-fire phenomenon of the CM 1 working at 312.9 MHz, we compare the MS curve of the transmitting CM 1 of the metallic Yagi-Uda antenna analyzed above and the MS curve of a fundamental mode of a metallic sphere with radius 32 mm (the modal analysis for the metallic sphere had been done in [55,Sec. 3.2.4] and [61]) in Fig. 14.…”