The invention discloses a multi-frequency antenna
system applicable to a mobile terminal with a
metal frame structure. The multi-frequency antenna
system comprises a
metal frame, a PCB and an antenna part. The
metal frame is designed to be part of an
antenna radiation body, two gaps are formed in the bottom portion of the metal frame, a feeding wiring part and the metal frame together form a T-shaped
monopole antenna or an IFA antenna so that the metal frame itself can be used for producing
low frequency and
high frequency resonance, and other
coupling parts can be additionally arranged to be used for adjusting the
low frequency and
high frequency resonance according to the needs of working frequency bands. The multi-frequency antenna
system has the advantages that due to the fact that the gaps of the metal frame are formed in the bottom portion, a user can be prevented from touching the gaps during the
actual use process, and the phenomenon that the performance of the antenna is poor when the antenna is held by a hand is avoided; the working frequency bands of the multi-frequency antenna system are 704Mhz-960Mhz and 1710Mhz-2700Mhz, and multi-frequency
broadband is realized; compared with a traditional general antenna, the multi-frequency antenna system is multiple in
frequency band and broad in frequency width; the antenna structure of the multi-frequency antenna system is small in occupied space, and
mutual influence cannot be generated between the antenna structure and surrounding environments.