IMAGING EXPERIMENT OF RECTANGULAR METAL WAVEGUIDE MODES BASED ON NEAR-FIELD ELECTROMAGNETIC WAVES SCANNING SYSTEMS

The research of rectangular metal waveguide modes is the key content of advanced optics and electrodynamics courses. In most of the existing college physics textbooks, the intrinsic electromagnetic field distribution of rectangular metal waveguide mode is obtained through formula derivation, while undergraduates lack intuitive perception of electromagnetic field distribution during the learning process. In this paper, the near-field electromagnetic scanning system is used to obtain the image of rectangular metal waveguide modes. Firstly, we measured the transmission coefficient of the rectangular metal waveguide and characterized the cutoff frequency of the waveguide modes. The electric field distribution of waveguide modes with different frequency was measured, and the experimental results were compared with the theoretical and numerical simulation results. The experimental results reflect the electromagnetic field distribution of the eigenmode vividly, which is helpful for students to understand and master the characteristics of the rectangular metal waveguide mode.