A lower bound of antenna efficiency based on the two-port model: How close is it?

The passive, unknown two-port antenna model that has been recently developed is used to investigate the loss and mismatch characteristics of an antenna. Previous work has shown that the two-port antenna model can be used to determine a lower bound of the antenna´s transmitting efficiency with data taken from a single antenna in a reverberation chamber. The limit of this calculation is that it relies on assumptions made in the two-port antenna model and provides only a lower bound of the antenna´s efficiency. One of the necessary assumptions is that the stirrer in the reverberation chamber is perfectly reflecting for at least a few positions.