Effect of a Large Rotating Scatterer in a Rectangular Cavity

摘要

In a mode-stirred chamber, the field in the cavity is perturbed with a stirrer or rotating scatterer so that the time-averaged field is constant. The report examines the fundamental properties associated with a perturbing body in a cavity and finds that the key to effective field perturbation lies in shifting the eigenmode frequencies. The shifting may be large enough that the new perturbed modes no longer resemble the original unperturbed modes. In effect, as the body rotates, different perturbed modes may be excited, thus introducing randomness into the system. Using the Transmission-Line-Matrix (TLM) method, the shifting of eigenfrequencies and the variation on the magnitude of the fields for different stirrer sizes are computed.