Abstract/Summary

It has been proved previously that in the field of microwave absorption, film and material are confused, and that the impedance matching theory (IM) which is usually applied to metal-backed film is inadequate. By analysis of experimental data from a novel theoretical perspective, it is shown here that the problems with IM cannot be solved even if different criteria such as the value of |Zin - Z0| or the phase difference between Zin (input impedance of film) and Z0 (characteristic impedance of open space or a layered material) are used and therefore the current theories related to IM need to be replaced by wave cancellation theory. The analysis in this work applies to published data and supports the new theories against the current ones. The conditions for the minima of reflection loss |RL| at large values of |Zin - Z0| have also been determined by transmission-line theory.