How to include element response in collectPlaneWave

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Chen
Chen on 6 Jan 2018
Edited: Honglei Chen on 8 Jan 2018
Hello
in the following code, I designed a spiral antenna (sa), and used the sa in a cavity backed spiral antenna (CBSA).
then I used the CBSA as the element in a 7-element array (DA03) using phased.ConformalArray.
S1 is the incoming signal with SNR 20dB.
My questions are:
1. although there is option in phased.SteeringVector called 'IncludeElementResponse', when I run the code it looks like there is no place to calculate CBSA response, since the calculation should take about 10 min to get CBSA current, pattern, ...?
2. How to make sure the collectPlaneWave include the CBSA response when it collects the signal S1, if the response of CBSA is not calculated?
Thanks
Chen
%--------------------------------------------------------------------------
sa = spiralArchimedean('Turns',9, 'InnerRadius',1e-3, ...
'OuterRadius',11e-3);
CBSA = cavityCircular('Exciter',sa,'Radius',12e-3,'Height',....
25e-3,'Spacing',23e-3);
%--------------------------------------------------------------------------
N2D=7;
p(:,1) = [ 0.0000; 0.0000; 0]; %DA03
p(:,2) = [ 25; 7.5; 0]; %DA03
p(:,3) = [ 7.5; 25; 0]; %DA03
p(:,4) = [-19; 17.5; 0]; %DA03
p(:,5) = [-26; -8.3; 0]; %DA03
p(:,6) = [ -8.3; -26; 0]; %DA03
p(:,7) = [ 17.5; -19; 0]; %DA03
p = p*1e-3;
a=zeros(1,N2D);e=90*ones(1,N2D);
DA03 = phased.ConformalArray('Element',CBSA,'ElementPosition',p,...
'ElementNormal',[a;e]);
%--------------------------------------------------------------------------
fc = 10*1e9;
Tc=1/fc;
df = 10e6; %df/2 is ESM frequency measurement uncertainty
WL = physconst('LightSpeed')/fc; %wavelength
t = linspace(0,2*Tc,400)';
dt=t(2);
SigAz = 10;
SigEl = 20;
% Incoming signals
S1 = 10*cos(2*pi*fc*t);
S1=awgn(S1,20,'measured');
% collect signal
yDA = collectPlaneWave(DA03,S1,[SigAz;SigEl],fc);
svDA = phased.SteeringVector('SensorArray',DA03,...
'IncludeElementResponse',true);
A=svDA(fc,[SigAz;SigEl]);

Answers (1)

Honglei Chen
Honglei Chen on 8 Jan 2018
Edited: Honglei Chen on 8 Jan 2018
I'm not an expert on CBSA, but steering vector computation does seem to account for the element response. When I ran your example, the magnitude of the elements in the steering vector is 0.427. If the element response weren't there, the magnitude values would have been 1.
collectPlaneWave does not consider element response. I would recommend to use phased.Collector to model receiving the signal. The collector does include the element response.
HTH

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