reading at UCA elements

Hi

I need to receive the signal at different elemnents of UCA

I am using the following code

        sUCA = phased.UCA('NumElements',5,'Radius',2.0);
        % First signal 
        t = linspace(0,0.3,300)';
        t1= zeros(size(t));
        t1(201:205)= 1;
        % Second Signal
        t2= zeros(size(t));
        t2(101:105)= 1;
        
        angle_of_arrival = [30;0];
        x = collectPlaneWave(sUCA,[t1 t2],angle_of_arrival',fc);
        subplot(221)
        plot(t,abs(x(:,1))); title('Element 1 (magnitude)');
        axis tight;  ylabel('Magnitude');
        subplot(222)
        plot(t,abs(x(:,2))); title('Element 2 (magnitude)');
        axis tight; ylabel('Magnitude');
        subplot(223)
        plot(t,abs(x(:,3))); title('Element 3 (magnitude)');
        axis tight; xlabel('Seconds'); ylabel('Magnitude');
        subplot(224)
        plot(t,abs(x(:,4))); title('Element 4 (magnitude)');
        axis tight; xlabel('Seconds'); ylabel('Magnitude');

The problem I am facing is that all the antennas are receving the same magnitude . But as far as my understanding the antenna at least one antenna should not receive the signal

Please suggest some thing Best Regards

Answer 1

[Honglei Chen]

Why would you say taht at least one antenna should not receive the signal? You are using isotropic element in the array so every element can receive the signal regardless the incoming direction. As to the magnitude, it is because the toolbox assumes that the signal is at far field so the signal strength is the same across the array.

HTH

[uzmeed]

I tried using the other type of antenna like Cosine and a custom design spiral but it did not work as well. What could be the reason then??

[Honglei Chen]

Ah, that is because you used collectPlaneWave which ignores the element response. See the Algorithm part of the documentation

https://www.mathworks.com/help/phased/ref/phased.ula.collectplanewave.html

Instead of using collectPlaneWave, replace it with

        sCollector = phased.Collector('Sensor',sUCA,'OperatingFrequency',fc);
        x = step(sCollector,[t1 t2],angle_of_arrival');
        

You should be able to see the effect of element response.

HTH

[uzmeed]

Thank you HTH

One thing more if you can guide me

Is the RootMUSIC algorithm is specific to circular array of Radars or it can be used any system where the UCA is used like RWR or ELINT

Regards

Uzmeed

[Honglei Chen]

The algorithm is for general purpose, not specific to radar.

[uzmeed]

Thank you so much