SMR 2D

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Maximum Velocity across structure

Model Description

The use of acoustic mirrors is typically used to reduce substrate losses in SMRs to maintain a high quality factor, a key performance metric for these types of filters.

To keep the waves from escaping into the substrate, an acoustic Bragg reflector is created by stacking thin layers of alternating stiffness and density. A common design criteria is to use quarter wavelength thick layers.

The simple 2D model consists of an Aluminum Nitride active layer on top multiples layers of  Silicon Dioxide and Tungsten and Silicon substrate.

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Half Symmetry Model Schematic

Parametric Variables

The base model allows the following design variables to be adjusted. By default, Aluminum Nitride thickness and number of  reflective layers (pairs) are set as design variables to be swept (indicated by *):

Parametric Variable

Description

Default Value

aln_thk*

Thickness of the active piezoelectric layer

2.75 µm

nlayers*

Number of Silicon Dioxide and Tungsten layers (pairs)

5

dev_wid

Width of active area

100 µm

sub_out

Substrate width to boundary

50 µm

subs_thk

Silicon substrate thickness

2 µm

 

Outputs

A wide range of outputs can be generated, including:

  • Electrical Impedance
  • Quality Factor
  • Mode Shapes (Harmonic Analysis)

 

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Example Post Processor Outputs

Runtime Statistics

Model size

29500 elements

Solve Time

201 s (2 CPU)

Core Hours

0.112

Memory Usage

7 MB

Recommended CPU Configuration

2 CPU

 Files

The following input files are required to run this model:

 

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