A FFC structure includes transmission line units and a second insulating jacket. The adjacent transmission line units are spaced. Each of the plurality of transmission line units includes one or more signal lines, a first shield layer, a first ground conductor, and a second shield layer. Each of the signal lines includes a signal conductor to transmit a data signal or a power, and a first insulating jacket enclosing the signal conductor. The first shield layer surrounds the signal line and is connected to the first insulating jacket of each of the signal lines. The first ground conductor transmits a ground voltage. The second shield layer surrounds and is connected to the first ground conductor and the first shield layer. The second insulating jacket encloses the second shield layer of the plurality of transmission line units.