近年來長程演進技術（Long Term Evolution，LTE）的發展，它改善了3G的空中接取技術，採用OFDM和MIMO做為其無線網路演進的核心技術，具有資源分配靈活、頻譜效率高、頻寬大、延遲率低的優勢。本文所提出之天線設計在小型化、在-10dB的標準下適用於多頻帶如LTE/WLAN/2G/3G，為核心理念；致力於提高輻射效率和增益，也是重要的成果。由於LTE須具備高速資料傳輸能力，為達到高速資料技術，可利用多根天線系統，稱為多輸入多輸出的（MIMO，Multi-In Multi-Out）。為致力於行動裝置的小型化，在MIMO系統內，多根天線之間，由於緊湊式的配置，會有訊號互相干擾的問題，使隔離度差。為此，本文中也提出兩種改善隔離度的方法，分別是覆蓋材料在微帶線上和在天線之間設計使用射頻電路，使其雜訊抑制皆能在-15dB之標準。

A Wireless Wide Area Network(WLAN) and Long Term Evolution(LTE) multiband antenna for planar device is proposed, which consist of two direct-fed monopole ,a coupled-fed monopole connecting to ground and a metal strip. The fundamental modes of these components form a low operating band from 0.73~0.88GHz, a high band operating band from 1.67~2.69GHz ,based on 10dB.It can be employed in LTE800 /1800 /2100 /2300/2500,WLAN,GSM180/1900,and UMTS applications. We also fabricate an architecture of MIMO system including two antenna which was proposed previously. We propose two method of isolation improving. One is covering material, the other is RF circuit. We use carbon which mixed the solvent of ITK5517 for the method of covering material. Though it had good performance for isolation improvement ,it's also reduced the antenna efficiency. Because of the reducing of isolation, we used RF circuit to isolation improvement. The method can improve isolation in part of band and it's doesn't affect the efficiency. The parameter S21 is always below -15dB, and the envelope correlation coefficient ECC is under 0.05 at applying band.

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