ZnO/IDT/金刚石结构SAW滤波器的设计和制作

Fabrication and Design of ZnO/IDT/Diamond SAW Filters

传统材料制备的声表面波(SAW)滤波器的中心频率f大多位于较低的频段(f<500 MHz),但是无线通信频段逐渐向着高频化的方向发展,因此在SAW器件领域中引入高声速材料如金刚石以提高中心频率成为一种必然趋势。基于金刚石材料、采用ZnO/IDT/金刚石新型结构,设计了交错叉指结构和镜像阻抗连接结构的叉指换能器(IDT)参数。通过优化的工艺制备流程,获得了金刚石SAW滤波器样品。最后采用RF探针台对样品进行了性能测试和数据分析。测试结果表明制备的SAW滤波器样品的测试结果与理论值比较符合,交错叉指结构滤波器获得了很低的插损,镜像阻抗连接结构滤波器有效地提高了带外抑制度。样品IDT指宽2μm,SAW滤波器中心频率可达0.775 GHz。

The frequency of the surface acoustic wave（SAW） filters fabricated by using traditional material locates on a low level.Wireless communication frequency is developing on the way of high frequency.So,exploring high velocity materials such as diamond to fabricate SAW filters is a trend.Based on diamond of high velocity material,the new SAW filters of ZnO/IDT/diamond structure was adopted.The sturcture parameters of cross interdigital transducer（IDT） and image impedance connection IDT were designed.By using optimized fabrication technology,the SAW filters of new structure were obtained.At last,the SAW filters′ samples were measured by using RF probe and the test data were analyzed.The test data of the SAW filters′ samples were in accord with the theory data.Cross IDT filters has a low insertion,and image impedance connection filters can improve out-band rejection effectly.The interdigital width of sample IDT is 2 μm.The center frequency of the new filters can reach to 0.775 GHz.