A full-band antenna includes a dielectric layer, and a first and a second patterned conductive layer provided on the dielectric layer. The first patterned conductive layer includes a feed portion and a loop portion outwardly extended from the feed portion. The loop portion defines a plurality of radiation sections, between which a multi-coupling effect is created to form at least one variable frequency. The second patterned conductive layer includes a conductive portion and a short-circuit portion. The conductive portion forms at least one fixed frequency. The at least one variable frequency of the loop portion can be adjusted in its frequency distribution and frequency range by changing a width of the radiation sections and a spacing distance between the radiation sections.