An inverted-F antenna comprises a microwave plate, a dielectric substrate, a radiating metal sheet, a ground surface, a shorting metal strip, and a feeding metal strip. The radiating metal sheet comprises a connecting metal sheet, first, second, and third child radiating metal sheets, a matching metal sheet, a slot, a shorting point, and a feeding point. The first child radiating metal sheet is for forming a low frequency operating mode. The second child radiating metal sheet is for forming a high frequency operating mode. The third child radiating metal sheet is for adjusting operating frequency and bandwidth of the second operating mode. The slot, the shorting point, and the feeding point are for adjusting impedance matching. The grounding surface is for increasing the operating bandwidth of the low frequency operating mode. The shorting metal sheet and the feeding metal sheet are for grounding the antenna and signal transmission.