A slot antenna comprises a printed circuit board, wherein the printed circuit board has a slot, a first capacitor, a radio frequency signal source, a transmission line, and a ground cable, wherein one end of the slot is open, and the other end is closed; the first capacitor and the ground cable are disposed on the printed circuit board, wherein the first capacitor is located on the open end of the slot; the transmission line connects the first capacitor to the radio frequency signal source; and the radio frequency signal source is configured to stimulate a feeding signal, and feed the feeding signal to the open end of the slot, wherein the radio frequency signal source connects the transmission line to the ground cable, and wherein a feed point from the radio frequency signal source to the transmission line is located outside the slot.