使用LCP軟性基板研製毫米波雙圓極化天線

本論文使用液晶聚合物Liquid-crystal polymer(LCP) 軟性基板研製毫米波雙圓極化天線，結構為 L型的單極天線和單饋入共平面波導結構產生兩個互相垂直的電場分量並激發圓極化，並且在共平面波導左側地附加I型Stub提供平衡垂直和水平之間的電流分布，添加兩個長方形元件則改善阻抗匹配和增強雙頻帶內的圓極化，此外，將雙頻毫米波濾波器整合天線抑制雜訊，射頻前端電路在單層LCP基板上實現，仿真模擬結果顯示回波損耗大於10-dB的第一和第二的操作頻帶分別為26.45-27.74GHz和36.73-38.48 GHz，小於3-dB Axial Ratio軸比的兩個操作頻帶分別為26.89-27.38GHz和36.26-42.42GHz，可用於未來第五代行動通訊設備上。 In this paper, a flexible substrate liquid crystal polymer (LCP) is used to realize both 27GHz and 38GHz millimeter wave dual circularly polarized antennas. The antenna based on the L-shaped monopole antenna and single-fed coplanar waveguide structure is proposed to generate two mutually perpendicular components of the electric field and exhibit circular polarization. The additional I-type Stub is attached on the left side of the ground to provide the balance between both horizontal and vertical current distributions . Two rectangular elements are added to improve impedance matching and enhance the circular polarization within two designed passbands. Besides, the dual-band mm-wave filter is integrated with the antenna to suppress the noise. The entire structure is implemented on the single layer LCP substrate. The simulation results show that the first and second operation bands from 26.45-27.74 GHz and 36.73-38.48 GHz have greater than 10-dB return loss. The Axial Ratio (AR) bandwidth of less than 3-dB for both operation bands are 26.89-27.38GHz and 36.26-42.42GHz respectively. It is expected to be applied in the fifth generation of mobile communication equipment in the future.