Integrative Electromagnetic Modal Analysis for the Waveguide-Antenna Cascaded Systems under the Energy Transport Theorem Framework

The energy transport theorem (ETT)-based decoupling mode theories (DMTs) for the feeding waveguides and transmitting antennas are simply reviewed, and the ETT-based DMTs (ETT-DMTs) are used to calculate the energy-decoupled modes (E-DMs) of a specific waveguide and a specific antenna. The mode-matching method for the waveguide-antenna cascaded systems is discussed, and a main drawback of the mode-matching method is exposed: the mode-matching method has only ability to study the interaction and inter-excitation processes between the E-DMs of waveguide and the E-DMs of antenna, but has no ability to analyze the inherent E-DMs of the whole waveguide-antenna cascaded system. To resolve this problem, an integrative modal analysis method is proposed to realize the modal analysis for the whole waveguide-antenna cascaded system.