researcher from the UK has put forward a theory for how the EmDrive, an electromagnetic propulsion drive, might work, a question which has puzzled scientists since Roger Shawyer first designed the system in 2001...
...More than eight tests in four independent labs have shown that when microwaves resonate within an asymmetric cavity, an anomalous thrust is generated pushing the cavity towards its narrow end," McCulloch wrote.
http://www.spacedaily.com/m/reports/Int ... a_999.html
http://arxiv.org/abs/1604.03449
It is looking interesting.