3-D radiation Pattern of a Dipole Antenna with code
%This program plots 3-D radiation Pattern of a Dipole
Antenna
%All the parameters are entered in the M-File
clear all
%Defining variables in spherical coordinates
theta=[0:0.12:2*pi];%theta vector
phi=[0:0.12:2*pi];%phi vector
l_lamda1=1/100;% length of antenna in terms of
wavelengths
I0=1;% max current in antenna structure
n=120*pi;%eta
% evaluating radiation intensity(U)
U1=( n*( I0^2 )*( ( cos(l_lamda1*cos(theta-(pi/2))/2) -
cos(l_lamda1/2) )./ sin(theta-(pi/2)) ).^2 )/(8*(pi)^2);
%converting to dB scale
U1_1=10*log10(U1);
%normalizing in order to make U vector positive
min1=min(U1_1);
U=U1_1-min1;
% expanding theta to span entire space
U(1,1)=0;
for n=1:length(phi)
theta(n,:)=theta(1,:);
end
% expanding phi to span entire space
phi=phi';
for m=1:length(phi)
phi(:,m)=phi(:,1);
end
% expanding U to span entire space
for k=1:length(U)
U(k,:)=U(1,:);
end
% converting to spherical coordinates
[x,y,z]=sph2cart(phi,theta,U);
%plotting routine
surf(x,y,z)
colormap(copper)
title('Radition Pattern for Dipole Antenna
(length=1.5lamda)')
xlabel('x-axis--->')
ylabel('y-axis--->')
zlabel('z-axis--->')
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