A Novel Coupling Structure for Tunable Handset Antenna Miniaturization
| Autor: | Dai, Da-Wei, 戴大為 |
|---|---|
| Rok vydání: | 2015 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 In this thesis, we propose a tunable handset antenna for 2G/3G/4G applications. Its frequency band can cover from 0.698 ~ 0.96 GHz and 1.71 ~ 2.69 GHz, and the lower frequency is tunable. With the development of wireless communication technology, people pursue a higher speed transfer rate. From previous 2G, 3G, present 4G and even 5G in the future…etc. Many new bands will appear and new mobile communication technology standard will be defined. The problems we will face eventually are not only being suitable with the new mobile communication technology standard, but also taking the compatibility of the existing networks into consideration. However, handset antenna is considered to achieve the purpose of miniaturization. Therefore, how to design a multi-band antenna in a small space will be a big problem in the future. This is the initial intention of this thesis to study a novel coupling structure to miniaturize tunable handset antenna. In addition to use the mechanism of tunable frequency to reach the miniaturization effect, the proposed novel coupling structure can achieve further miniaturization effect. 4G, LTE 700 makes it more difficult to miniaturize handset antenna. In general, we usually use the method of several resonance frequencies in design in order to cover the frequency band from 0.698 GHz to 0.96 GHz. That is, try to design several resonance frequencies in the lower band within a close frequency range, so that we can achieve the effect of broadband. But this way to broaden the frequency band will run counter to the miniaturization, so by using the tunable frequency mechanism can overcome the above problem to achieve the miniaturization of antennas. In the documents of frequency tunable antenna, most of them use the branch structure to meet the range of higher frequency band (1.71 ~ 2.69 GHz) or the lower band. This branch structure will also needs more space. In this thesis, the antenna which is designed is based on PIFA structure, and we use a novel coupling structure which can make low and high frequency resonance share the same current path in replace of the branch structure. It’s composed of the feeding strip and the shorted strip. Using coupling feed to make the shorted strip produce a low frequency resonance. Besides the current which flow from shorted strip through via to the ground, the coupling effect between shorted strip and the ground also produces a high frequency resonance. With the design of meander line structure, it can not only reach the boundary condition of the third harmonic of the fundamental frequency, but also produce one more high frequency resonance by the coupling effect of the meander line and the ground. This is the way to achieve the high frequency band. The thesis proposes a novel coupling structure to miniaturize tunable handset antenna by using the tunable frequency mechanism of the lower band and make the low and high frequency resonance share the same current path by this coupling structure in replace of the branch structure to achieve further miniaturization effect. The size of the proposed antenna is only 13.5×24 mm^2. The details of designing antenna and the results of experiments are discussed in this thesis. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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