Simple Python package for the design and modelling of Interdigital Transducers (IDTs).
Project description
idtpy
idtpy
is a simple Python package for the design and modelling of Interdigital Transducers (IDTs).
IDTs are widely used in telecommunication industries as filters or delay lines. It is composed by surface metallic electrodes deposited on a piezoelectric substrate. Applying an oscillating input signal, a surface acoustic wave (SAW) is generated thanks to the piezoelectric coupling. The properties of this emitted SAW is determined by the design of the electrodes. Changing the unit cell pattern allows for instance extension in the frequency band response (chirp IDT), unidirectional emission (Dart IDT) or generation of higher harmonics (Split 52 IDT).
The goal of idtpy
is to become a user-friendly tool to work with IDTs, covering from the design process with physical parameters
to simple modelling of the transducer response.
Cite
If you use idtpy
in any scientific publication, please, cite it as XXX.
Installation
Requirements
You need a working Python 3.8 installation to be able to use idtpy
.
We highly recommend installing Anaconda which takes care of installing Python and managing packages.
Make sure to download a Python version equal or higher than 3.8.
Dependencies:
- Python (tested with 3.8)
- NumPy -
conda install numpy
- Gdspy (optional: to import gds files) -
pip install gdspy
- Matplotlib (optional: to visualize imported polygons) -
conda install matplotlib
Linux / OS X / Windows
Option 1: Using pip
Simply open Anaconda prompt and type:
pip install idtpy
Option 2: From the source code
- Download the source from github
- Open Anaconda prompt
- Go to the directory of the
idtpy
project - Build/install by typing:
python setup.py install
Examples
More examples can be found in the folder 'examples'.
Create an IDT
from idtpy import designer
reg = designer.Regular(
freq=1, # resonant frequency
vsaw=1, # SAW speed
Np=10, # number of periods
w=30, # overlap width between opposite electrodes
l=20, # vertical length after the overlap
Nehp=1, # number of electrodes per half period. 1=single-finger, 2=double-finger...
tfact=1, # thickness factor
)
Preview it with matplotlib
import matplotlib.pyplot as plt
fig, ax = plt.subplots(1)
reg.show(ax, color='k')
Make it double finger easily
reg = designer.Regular(
freq=1, # resonant frequency
vsaw=1, # SAW speed
Np=10, # number of periods
w=30, # overlap width between opposite electrodes
l=20, # vertical length after the overlap
Nehp=2, # number of electrodes per half period. 1=single-finger, 2=double-finger...
tfact=1, # thickness factor
)
Add dummy electrodes
dummies = reg.dummies(gap=5)
reg.show(ax, color='k')
dummies.show(ax, color='r')
Create a chirp IDT
chirp = designer.ExpChirp(
fmin=1, # minimum frequency
fmax=4, # maximum frequency
T=10, # IDT length in time
vsaw=1,
w=30,
l=20,
Nehp=2,
tfact=1,
)
Model the frequency response
import numpy as np
from idtpy import model
freq = np.arange(1, 6, 0.001)
idt = model.ExpChirp(fmin=2,fmax=5,T=40,phi0=0,t0=0)
f_res = idt.freq_response(freq, apodized=False, db=True, shp=1).real
plt.plot(freq, f_res, 'k')
Predict the SAW shape with an input voltage
dt = 0.001
input_signal = model.ExpChirp(fmin=2,fmax=5,T=40)
ideal_wf = idt.apply_waveform(input_signal, dt)
time = np.arange(0, 80, dt)
t_res = ideal_wf.time_response(time).real
plt.plot(time, t_res, 'k')
Split52 design
split = designer.Split52(
freq=0.5,
vsaw=1,
Np=5,
w=30,
l=20,
tfact=1,
)
Dart design
dart = designer.Dart(
freq=1,
vsaw=1,
Np=10,
w=30,
l=20,
tfact=1,
direction='r',
)
Version 0.1.0 (Month day-th, 2021)
- Initial release
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