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现在,SAW谐振器已经在1.5千兆赫附近工作。现在已经能生产频率比过去的高一个数量级的,稳定的基模振荡器和高Q滤波器。这些SAW器件,可以使现代通讯和雷达系统的分系统或组件变得比较小,简单,并降低功耗。在本文中将讨论工作于0.5—1.5千兆赫之间的SAW谐振器的基本结构,制作技术和特性及其应用。 最简单的声表面波(SAW)谐振器,等价于已广泛使用于振荡器和窄带滤波器的声体模式晶体谐振器。一个SAW谐振器,由表面上有两个分布式反射器和一个或几个电-声叉指换能器的压电晶片构成。反射器应构成一个能够约束表面波的谐振腔,而叉指换能器应能使能量进入并离开谐振腔。图1是一个SAW
SAW resonators are now operating around 1.5 GHz. It is now possible to produce stable, fundamental-mode oscillators and high-Q filters an order of magnitude higher than in the past. These SAW devices can make the subsystems or components of modern communications and radar systems smaller, simpler, and reduce power consumption. In this paper, the basic structure, fabrication techniques and characteristics of SAW resonators operating at 0.5-1.5 GHz and their applications will be discussed. The simplest surface acoustic wave (SAW) resonators are equivalent to the acoustic mode crystal resonators that are widely used in oscillators and narrowband filters. A SAW resonator consists of a piezoelectric wafer having two distributed reflectors and one or more electro-acoustic interdigital transducers on the surface. The reflector should form a resonant cavity that can confine the surface wave, while the interdigital transducer should allow energy to enter and leave the cavity. Figure 1 is a SAW