I. Introduction
Flexible electronics including the surface acoustic wave (SAW) device have been intensively studied because of the excellent bendability, conformal contact with curve surface and light weight. This technology has been extended as an advance technology in this era. SAW device are one type of basic and essential electronic device. It is used widely in the electronics and communications field as an oscillator, filter and sensor application. Therefore, the flexible SAW devices have been expansively explored for application as a micro sensor to measure the physical parameters and to detect biochemical substances due to high sensitivity at high operating frequency [1]–[5]. SAW device also have been discovered to be used as actuators for microfluidics and lab-on-a-chip devices [6]–[10].