Antenna Array  - Steering

 

 

In this tutorial, you will see the examples of beam steering in horizontal direction (changing the direction of the beam) for various array antenna.

You would notice that the shape of the beam does not change (distorted) much as beam steers in large angle when the number of elements is large, but the beam shape distorts as beam steers in large angle when the number of elements is small.

 

Click on Next and Prev button so that some intuitive images forms in your head.

 

For more theoretical explanation related to these slides, I would suggest you to look into another form of my notes listed below.

 

 

 

 

Followings are the code that I wrote in Matlab Phased Array System Toolbox  to creates all the plots shown in this page. You may copy these code and play with these codes. Change variables and try yourself until you get your own intuitive understanding.

 

< Code 1 >

 

c = 3e8;        % propagation speed

fc = 26e9;      % carrier frequency

lambda = c/fc;  % wavelength

 

ArrayDim = [16 2];

txarray = phased.URA('Size',ArrayDim,'ElementSpacing',[lambda/2 lambda/2]);

txarray.Element.BackBaffled = true;

 

steer_ang = [0;0];

stv = phased.SteeringVector('SensorArray',txarray);

w = stv(fc,steer_ang);

 

hFig = figure(1);

pattern(txarray,fc,[-180:180],[-90:90],...

    'PropagationSpeed',c,...

    'CoordinateSystem','polar',...

    'Type','powerdB',...

    'Weight',w);

set(gcf,'color','w');

 

axis([-50 50 -50 50 -50 50]);

axis off;

%view(90,15);

view(135,15);

 

sTitle = sprintf("Antenna Array = %d by %d, Steering Angle=[%d %d]", ...

                     ArrayDim(1),ArrayDim(2),steer_ang(1),steer_ang(2));

title(sTitle);

set(hFig,'Position',[300 100 800 700]);