Nowadays, antennas with various sizes are developed to be applied to various hand-held electronic devices or wireless transmitting devices, e.g. the access point (AP). For example, the single-frequency band (2.4 GHz) of the inverse-F antenna (IFA), which can be easily disposed on the inner wall of the hand-held electronic device, is already in widespread existence. Due to the requirement of the user for the voice, image, multimedia communication service quality and transmission speed, the more advanced wireless communication technology, e.g. the 4G long term evolution (LTE), is applied to the hand-held electronic device which emphasizes the lightness, flimsiness and miniaturization. Therefore, the antenna also has to be capable of being used in the multi-frequency band of the LTE system, from the low frequency (690-960 MHz) to the high frequency (2.3-2.5 GHz), and possess a good transmission ability. The conventional antenna which can be applied to the multi-frequency band system has a complex structure or a large size.
In order to overcome the drawbacks in the prior art, an external LTE multi-frequency band antenna is provided. The particular design in the present invention not only solves the problems described above, but also is easy to be implemented. Thus, the present invention has the utility for the industry.