Numerical analysis of two-dimensional piezoelectric waveguides for surface acoustic waves by finite-element method

1981 ◽  
Vol 17 (17) ◽  
pp. 609 ◽  
Author(s):  
M. Koshiba ◽  
M. Okada ◽  
M. Suzuki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Analysis ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Two Dimensional ◽  
Element Method

Ladder Type of Leaky Surface Acoustic Waves Filters on Substrate of Lithium Niobate

2021 ◽  
Vol 23 (3) ◽  
pp. 139-147
Author(s):  
A.S. Koigerov ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Acoustic Waves ◽  
Communication Systems ◽  
Surface Acoustic Waves ◽  
Bandpass Filters ◽  
The Finite Element Method ◽  
Frequency Responses ◽  
Method Of Extraction ◽  
Element Method

High requirements on the electrical parameters of the filters are made in wireless radio communication systems. A number of tasks require bandpass filters with relative bandwidths of 8-12 %. In this case, the filter must have insertion losses of not more than 10 dB, have a rejection is not worse than 40 dB, unevenness in the bandwidth of not more than 1 dB. In addition, the amplitude frequency responses of the filter must have steep slopes due to the closely spaced frequency bands of neighboring communication systems. Due to its small size and other advantages, ladder resonator filters on surface acoustic waves are widely used in communication systems. To realize the high requirements of this type of filters, it is necessary not only to select all the topology parameters of the individual resonators included in the filter very accurately, but also to have a good computational theory and the necessary material parameters for the selected model at the design stage. Purpose: to show on the example of comparison of calculated and experimental frequency responses of ladder filters the validity of the method of extraction of the necessary parameters obtained for an infinite periodic structure by the finite element method for calculating of finite structures of real inter digital transducer and reflective gratings. Results: the method of extraction of parameters necessary for calculation by the method of connected modes on the basis of P-matrices is offered. The technique is based on the analysis of infinite periodic electrodes by the finite element method. Bandpass filters with a relative bandwidth 8-12 % on a piezosubstrate 49° YX LiNbO3 were designed and manufactured based on the proposed theory. It is shown that for this material, the calculation must take into account the direct radiation of bulk acoustic waves, since the design of ladder type filters, the radiation falls into the projected bandwidth of the filters. These calculations are confirmed by the results of experiments.

ANALYSIS OF SAW EXCITATION AND PROPAGATION UNDER PERIODIC METALLIC GRATING STRUCTURES

2000 ◽  
Vol 10 (03) ◽  
pp. 685-734 ◽  
Author(s):  
KEN-YA HASHIMOTO ◽  
TATSUYA OMORI ◽  
MASATSUNE YAMAGUCHI
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Field Analysis ◽  
The Finite Element Method ◽  
Numerical Techniques ◽  
Metallic Grating ◽  
Propagation Properties ◽  
Element Method

This paper reviews numerical techniques used for the analysis of excitation and propagation properties of surface acoustic waves (SAWs) under periodic metallic grating structures. First, the finite element method (FEM), the boundary element method (BEM) and the spectral domain analysis (SDA) are compared for the SAW field analysis. Then it is shown how skillfully excitation and propagation properties are characterized by using the FEM/SDA technique. Extended FEM/SDA theories are also detailed for the analysis of multi-finger grating structures.

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