Antenna Array - URA(Uniform Rectangular Array) : N x N   In this tutorial, you will see 3D radiation pattern with various radiation pattern. In all of these array, the number of elements in both vertical and horizontal direction changes. Pay attention to how the radiation pattern changes as the number of elements in both direction increases. You would see as the number of elements increases the beam pattern is compressed more in that direction(i.e, the width of beam in horizontal direction gets narrower). Since the number of elements increases in both horizontal and vertical direction, the beam width gets compressed both in horizontal and vertical direction resulting in that the beam width gets narrower in 3D space.   The principle here is the more antenna elements in a direction, the narrower the beam width gets in that direction.   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]);