In article ,
says...

This research report appears to raise more questions.
Why is thrust produced?

Electric current through the cables interacting with the earth's
magnetic field.

Without knowing the interior cavity field that
causes thrust it is impossible to infer the field that
will cause no thrust.

Nothing going on in the cavity is causing the "thrust".

Looking for cable forces is certainly an issue. But
there are no reports of cable force. A cable drive
needs to be tested evidently.

Google: electrodynamic tether

The above is a far more efficient way to generate "thrust" in the
earth's magnetic field. This microwave cavity thing does nothing
advantageous.

Jeff
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