A flexible printed circuit (FPC) board having reinforcing pattern against bending is disclosed. The FPC board provides an RF interconnection extending from an RF electrode. Two ground electrodes are formed in respective sides of the RF electrode. The ground electrodes extend respective extended portions along the RF interconnection to protect the RF interconnection from breakage due to bending of the FPC board. The extended portion provides an end portion bent toward the RF interconnection to compensate for impedance mismatching of the RF interconnection.