Investigation on SAW properties of LGS and optimal cuts for high-temperature applications.
Investigation on SAW properties of LGS and optimal cuts for high-temperature applications.
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DOI：
10.1109/tuffc.2005.1561677
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发表时间：
2005-12
期刊：
影响因子：
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通讯作者：
Xiaojun Ji;Tao Han;W. Shi;Guowei Zhang
中科院分区：
文献类型：
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作者：
Xiaojun Ji;Tao Han;W. Shi;Guowei Zhang
蓝晶石(LGS)为声表面波(SAW)器件在高温下的应用开辟了广阔的前景。研究了LGS在250℃下单次和双次旋转切割时的声表面波特性。提出了高温下锯切方向和传播方向的三个显著区域，并分别由欧拉角[0度，20度-->50度，35度--45度]、[0度，85度-->110度，0度-->5度]和[0度，138度-->145度，20度-->23度]定义。第一个区域包括零或相对较小的延迟温度系数(TCD)(0.45%)，最后一个区域具有较大的TCD(25-30ppm)。对于上述三个区域内的一些典型取向，讨论了声表面波特性(最高可达1000℃)的温度依赖性。第二个区域[0度，85度->110度，0度-->5度]，特别是取向[0度，90度，0度]，具有更好的声表面波综合特性，更适合高温应用。因此，在设计高温SAW器件时，应优先考虑[0度、90度、0度]的取向。将已发表的实验结果与文献中基于LGS常数及其温度系数的数值预测结果进行了比较，发现250℃下TCD的理论结果与实验结果是一致的(TCD的相对误差在10%以内)。
A promising perspective for surface acoustic wave (SAW) device applications at high temperature has been opened by langasite (LGS). The SAW properties of LGS in singly and doubly rotated cuts at 250 degrees C are investigated. Three noticeable regions for SAW-cut orientations and propagation directions at high temperature are put forward and are defined by Euler angles [0 degrees, 20 degrees --> 50 degrees, 35 degrees --> 45 degrees], [0 degrees, 85 degrees --> 110 degrees, 0 degrees --> 5 degrees], and [0 degrees, 138 degrees --> 145 degrees, 20 degrees --> 23 degrees], respectively. The first region includes zero or comparatively reduced temperature coefficient of delay (TCD) (0.45%) and larger TCD (25-30 ppm) characterize the last region. For some typical orientations within the above-mentioned three regions, the temperature dependency of SAW characteristics (up to 1000 degrees C) is discussed. The second region [0 degrees, 85 degrees --> 110 degrees, 0 degrees --> 5 degrees], especially the orientation [0 degrees, 90 degrees, 0 degrees], has better comprehensive characteristics of SAW and is more suitable for high-temperature applications. Therefore, we should give a top priority to the orientation [0 degrees, 90 degrees, 0 degrees] in the design of SAW devices operating at high temperature. Comparison between published experimental results and numerical predictions based on LGS constants and their temperature coefficients available in the literature reveals that the theoretical results of TCD under 250 degrees C are in agreement with the experimental ones (the relative error of TCD is within 10%).