| In the last decades, wireless communication technology develops rapidly. Market demands for wireless mobile terminal like mobile phones are increasingly high. As a key component in modern mobile phone terminal system, antenna plays a role of effectively receiving and sending electromagnetic wave. Performance of antenna can not only influence communication quality, but also influence the power dissipation radiation and external structure of mobile phone. At present, plane-printed antenna produced through advanced printing circuit technique and processing, featuring convenient to processing, light in weight, low cross section and easy to be integrated with active device and microcircuit, has attracted great attention and has become a hot topic in research. However, to realize small size, multi-frequency band and wide frequency band for such antenna, there is still a long way to go. This paper, combining scientific research with requirements of various wireless communication system, explores and studies multi-frequency band and broadband plane-printed micro-strip monopole antenna. Major works of the author as well as the creative achievements the author made are as follows:Base on coupled feed technology, a small size of 23.5×15×0.5mm3 planar-printed phone antenna is researched and designed. The proposed antenna is composed of the driving unit, the coupling unit and the branch unit. The coupling unit and the branch unit produce resonance at low frequencies section respectively, controlling the low frequency operating bandwidth simultaneously, and the main control of high frequency drive unit operating bandwidth. The driving unit mainly controls the working bandwidth of the high frequency section. According to the calculation, simulation and optimization of antenna size parameters, the antenna was actually produced and tested. The result shows that the proposed antenna can generate multiple resonant modes at lower and upper bands for CDMA800/GSM1800/1900/UMTS and LTE2300/2500 bands.The measured results is basically consistent with the software simulation results to achieve the design requirements.A three-layer multi-band frequency broad-frequency band printed monopole antenna in small size based on double helix structure is designed. The antenna can radiate branch current path through helix buckling, so as to realize a small size—26×14×1mm3. The antenna can also work under multi-frequency bands, such as LTE700/2300/2500, WCDMA and WLAN-2.4GHz. Besides, with its three-layer structure, compared with single-plane antenna, the resonance performance of the antenna is improved significantly. The author made the experiment model of the aforesaid antenna by simulating optimized antenna parameters and conducted tests carefully. According to the test result, the antenna has sound radiation characteristic, high efficiency and gain, which almost conforms to all the simulation result and can be applied in various communication systems. |
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