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Impulse Response of a SAW Sensor

Mohamed Ashour
Hi,

I've been working on a SAW Simulation for several months, i've been good using frequency response analysis approaches however i want to understand how this paper works
www.google.com.eg/url?sa=t&rct=j&q=comsol+saw+zhang&source=web&cd=1&ved=0CBwQFjAA&url=http%3A%2F%2Fwww.comsol.com%2Fpapers%2F1503%2Fdownload%2FZhang.pdf&ei=a8CiUNCYIMfUsga86IDgCg&usg=AFQjCNHboSYAnjrQ7_5hNS_kf-gTc0c6cg&cad=rja

I've replicated the geometry and the conditions i used a step of 0.1ns and a total runtime of 200ns i've deconvoluted the output using matlab using this code

I = ifft(fft(v)./fft(i) ,'symmetric')
y=I;
Vin = 0.5;
Samplingtime = 0.1e-9
L=length(y);
NFFT = 2^nextpow2(L);
Y = fft(y,NFFT)/L;
Fs = 1/(Samplingtime)
f = Fs/2*linspace(0,1,NFFT/2+1);
%plot(f,2*abs(Y(1:NFFT/2+1))); %Plots Spectrum
Vf=2*abs(Y(1:NFFT/2+1));
Vf= Vf./Vin;
title('Insertion Loss')
xlabel('Frequency (Hz)')
ylabel('Insertion Loss(dB)')
plot(f,20*log10(Vf)); %Plots Insertion Loss

however i still can't get the same results as in the paper any suggestions?

thanks


1 Reply Last Post Sep 18, 2015, 2:13 PM EDT
COMSOL Moderator

Hello Mohamed Ashour

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Posted: 2 years ago Sep 18, 2015, 2:13 PM EDT
your input signal function is probably deferent then the one in the paper, i could not download the ppr but i suppose in the ppr the input is an impulse function (+Vi,-Vi), may be you used sine function V_in=A*sin(2*pi*f0*t), you will have different result in this case. i know you probably dont need the answer after three years but this may be helpful for some one els :)
your input signal function is probably deferent then the one in the paper, i could not download the ppr but i suppose in the ppr the input is an impulse function (+Vi,-Vi), may be you used sine function V_in=A*sin(2*pi*f0*t), you will have different result in this case. i know you probably dont need the answer after three years but this may be helpful for some one els :)

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