High Accuracy Modeling Method for Transmission Line on Surface Acoustic Wave Substrates

A high accuracy modeling methodology for electrical characteristics of transmission electrodes on SAW substrates is established. In order to design SAW filter accurately, it is necessary to extract precise SAW material parameters from the measurement value of the reference SAW resonator. When measuring the SAW resonator, transmission lines are needed for feeding to contact probes. De-embedding procedure, which removes the influence of transmission lines, is very important for accurate characterization of the SAW resonator.In this paper, we apply the improved de-embedding procedure using SHORT, OPEN and THRU calibration patterns. The de-embedded transmission line is separated four parts and extracted the RLGC equivalent circuit model for each part. Furthermore, we derive the frequency characteristic of resistance element of the transmission line. Finally, de-embedding the transmission line accurately, we can get intrinsic characteristic of the SAW resonator. This method must be very useful to extract SAW material parameters and we can design SAW filters more effectively.