The invention relates to a square three-frequency antenna device and communication equipment. The device comprises a
dielectric layer, a
radiation part, a grounding part, and an excitation part, wherein the
radiation part is arranged on the upper surface of the
dielectric layer, and the grounding part is arranged on the lower surface of the
dielectric layer; the excitation part is used for connecting the
radiation part with the grounding part to form a
current loop; the radiation part comprises a first rectangular
resonance body and a second rectangular
resonance body which are perpendicular to each other; and the grounding part comprises a first rectangular
metal patch and a second rectangular
metal patch which are perpendicular to each other. The square three-frequency antenna device isa built-in onboard antenna with three frequency bands, the antenna device utilizes the square and annular structures and the vertical rectangular resonators to realize coverage of
multiple frequency bands, and the antenna device is high in
gain, small in occupied size, relatively high in bandwidth, easy to manufacture and capable of radiating backwards, so energy efficiency of the antenna device is improved on the whole.