模擬與實測結果顯示，在共同接地面引進狹長槽孔的垂直置放天線結構，能有效抑制耦合，避免MIMO天線元件的相互干擾；此設計技巧不需額外的主被動元件，亦可減少所需的FR4基板尺寸，且此設計能符合S參數S11<-10dB,S12<-20dB的業界需求，其應用範圍涵蓋IEEE(802.11a/b/g/n/ac)等WLAN頻段。 This thesis is to investigate the MIMO dual-band antenna design for the isolation improvement with two antenna elements perpendicularly placed in a small device. The MIMO antenna consists of two antenna elements, of which each element consists of two antenna components: one is a narrow slit antenna, which is responsible for the radiation at low band (2.4GHz), the other is a dipole antenna, which serve as the load of the previous narrow slit antenna and is responsible for the high-band (5~6GHz). These two antenna elements are perpendicularly placed in order to achieve the polarization diversity, such that the coupling between the antenna elements can be reduced. In this thesis, several different design techniques are explored for the possibility to further enhance the isolation. Simulated and experimental results show that the introduction of a narrow slit, in the common ground plane of the two planar antenna elements placed perpendicularly, can effectively inhibit the coupling to avoid mutual interference of the MIMO antenna element. This design skill can reduce the FR4 substrate size required, and doesn''t need additional active and/or passive components. Also, this antenna design is able to meet the industry demands of S-parameter (|S11|<-10dB, |S12|<-20dB), and its scope of application covers IEEE (802.11a / b / g / n / ac) WLAN band.