A New-Type Surface Acoustic Wave Filter
Date Issued
2014
Date
2014
Author(s)
Feng, Yi-Shuo
Abstract
This thesis proposed that if we bond a piezoelectric material on substrate which deposited the electrodes and etched trenches between the electrodes, we can exclude mass and stiffness effect by IDTs (Inter digital transducers) on substrate. Through this method, we can let the SAW propagate on clean and flat piezoelectric material achieves more accurate filtering effect. This method not only eliminates the cost of trimming, but also provides the good protection ability to the filter.
First, this thesis chose the ST-cut quartz piezoelectric as material to transfer SAW, and used Z-cut quartz as bottom substrate and build IDTs on its top. Then we etched a trench between the IDTs. Last of all we used SU8-1040 to bond ST-cut quartz and Z-cut quartz together.
Through the above method we successfully manufacture a two ports SAW filter by ST-cut quartz. The electrode period is 88μm and the theoretical value of center frequency is 35.8773MHz. The center frequency of the filter with the theoretical error only one-thousandth, and the surface of wave propagation is between two wafers, it will let the filter hermetic packaged directly. By eliminating the step of trimming and extra package, we can develop a low-cost and small SAW filters.
Subjects
表面聲波濾波器
壓電材料
指叉電極
SU-8 接合
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-103-R00522536-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):ba7f1ae44f0fb2a5a727633cbc46b679