Design, fabrication and RF performances of two different types of piezoelectrically actuated Ohmic MEMS switches
Design, fabrication and RF performances of two different types of piezoelectrically actuated Ohmic MEMS switches
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DOI：
10.1088/0960-1317/15/11/015
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发表时间：
2005-11-01
影响因子：
2.3
通讯作者：
Bu, JU
中科院分区：
文献类型：
--
作者：
Lee, HC;Park, JH;Bu, JU
在本文中，我们提出，制造和特点的压电驱动RF MEMS（射频微机电系统）开关。它们被设计为在低工作电压下工作，适用于高级移动的/无线手持设备应用。所提出的开关主要由压电悬臂梁致动器与Au接触电极和CPW（共面波）传输线悬挂在基板上。已经提出了两种不同类型的RF MEMS开关以找到更好的几何形状。一种是由一个压电悬臂梁和一个用三个铰链连接在其边缘的接触电极组成的结构（A型），另一种是由四个压电悬臂梁通过每个铰链对称地组合在一起，以支撑一个中心接触电极（B型）。两种不同的制造（A型和B型）RF MEMS开关在2.5 V的工作电压和2 GHz的频率下分别具有-0.22和-0.23 dB的插入损耗。虽然它们的插入损耗差别不大，但它们之间存在着不同的插入损耗对外加电压的依赖关系。由于接触电极与信号传输线之间的接触面积是可变的，因此A型开关的插入损耗随工作电压的变化而变化。同时，B型开关表现出几乎恒定的插入损耗，而不管操作电压。A型和B型开关在2 GHz频率下的隔离值分别为-40.8和-42.5 dB。
In this paper, we have proposed, fabricated and characterized piezoelectrically actuated RF MEMS (radio-frequency micro-electro-mechanical system) switches. They have been designed to operate at a low operation voltage for advanced mobile/wireless handset applications. The proposed switches are largely composed of piezoelectric cantilever actuators with an Au contact electrode and CPW (coplanar wave) transmission lines suspended over the substrate. Two different types of RF MEMS switches have been suggested to find the better geometry. One has the structure of one single piezoelectric cantilever and a contact electrode attached to its edge with three hinges (type-A), and the other contains four piezoelectric cantilevers that are symmetrically combined through each hinge to support a centered contact electrode (type-B). The two different fabricated (type-A and type-B) RF MEMS switches have insertion losses of -0.22 and -0.23 dB at an operation voltage of 2.5 V and a frequency of 2 GHz, respectively. Although the difference in insertion loss is trivial, there exist different dependences of insertion loss on applied voltage between them. The insertion losses of type-A switches are changed with varying operation voltage because the touching area between the contact electrode and the signal transmission lines is variable. Meanwhile, the type-B switches show nearly constant insertion losses regardless of operation voltage. The type-A and type-B switches have isolation values of -40.8 and -42.5 dB at a frequency of 2 GHz, respectively.