Mystery Component - 3 pin device with printed circuit pattern
If both sides have only pcb patterns, it cannot be nothing else than a LC circuit - a filter or matcing network is my trivial quess. Seems to be quite complex due the coupling between the coils. No high power capacity. 

Because it is a separate part which is not integrated into the main board proposes that it is selected differently for  different marketing areas due different requlations. That is not a proof because the main board simply can have too lossy material.

The size proposes it is used at several hundred MHz. The stray capacitances  and inductances of ordinary wires makes all measurements useless if proper UHF probes and instruments are not available. 

Computer aided reverse engineering is possible by using high cost microstrip circuit analyzing software. But some idea of what to ask is a must.