Synthesis of Ladder-type Radio Frequency Surface Acoustic Wave Filter Based on Lumped Circuit Model by Using Neural Network

Abstract

With the development of mobile communication technology, the demand for mobile devices continues to rise. Acoustic devices such as radio frequency (RF) filters and duplexers are widely used in mobile handsets because of their excellent electric performance characteristics. However, the key bottleneck is how to convert a lumped circuit model into the structure parameters of an acoustic resonator for RF circuit designers so that they can apply RF circuit design tools in designing surface acoustic wave (SAW) devices. The neural network (NN) has been widely applied in various science and management areas for its powerful learning and mapping capabilities. In this paper, a method of building a bridge between the lumped equivalent circuit (EC) model and structure parameters of a SAW resonator is proposed. The approach begins with establishing a database that shows the relationship between the values of the lumped EC and corresponding structure parameters of the SAW resonator. A four-layered NN with the back-propagation (BP) algorithm is adopted to determine the relationship between the structure parameters of the SAW resonator and the lumped EC. Then, other input/output pairs are presented to check if the estimated lumped EC matched with original circuit. Finally, as an example, the design of a long term evolution (LTE) transmitter (Tx) filter is developed to demonstrate the proposed approach.

A brief investigation of one-port SAW resonator for the application in communication systems

“…Many parameters have also been started and thus useful to design and optimize device that relies on 6H-SiC/ZnO layered structure [53]. However, the performance of the device could be enhanced and might be achievable through the optimization of the device design, quality of the film refinement, doping of the piezoelectric film as well as utilization of various substrate and IDT configurations [54]. The SAW phase velocity in multilayer structure has not been associated with the propagation direction.…”

Development and Application of SAW Filter

“…How to convert the lumped circuit model into the structural parameters of the acoustic resonator is the key bottleneck for RF circuit designers to use RF circuit design tools to design SAW devices. In 2019, Mei-Hui Chung proposed a method to establish a bridge between the lumped equivalent circuit model of the SAW resonator and the structural parameters [ 83 ]. Using a four-layer neural network and BP learning algorithm, the SAW resonator corresponding to the lumped EC was obtained.…”