# Hello, I am trying to plot radiation intensity of antenna using the following code but i am not getting polar plots with theta axis and polar, grids please help me. help me

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Alexander on 4 Apr 2013
Answered: Sandip Ghosal on 23 Jun 2021
i resolved the problem but i am not getting polar plots in degree co-orditanates. can any body please help me . I have attached the graph and here is my code. PI = 4.0*atan(1.0); E = 120.0*PI;
L=1/4; A = L*PI; Io = 1; r=2;
k=2*pi;
THETA=0:0.01:2*pi; U =((cos(k/2*L.*cos(THETA))-cos(k/2*L))./sin(THETA)).^2*(E./(8.0*PI^2));
polar(THETA,U);

Sandip Ghosal on 23 Jun 2021
Hi,
The following code works fine.
PI = 4.0*atan(1.0);
E = 120.0*PI;
L=1/4;
A = L*PI;
Io = 1;
r=2;
k=2*pi;
THETA=0:0.01:2*pi;
U =((cos(k/2*L.*cos(THETA))-cos(k/2*L))./sin(THETA)).^2*(E./(8.0*PI^2));
polar(THETA,U);
polar(THETA, RHO) makes a plot using polar coordinates of the angle THETA, in radians, versus the radius RHO. For more details of polar plot, please run:
help polar

Michael on 4 Apr 2013
Hmm.
PI isn't the same as pi. Use "pi". what is "E"? Is it "exp(1)"? if you fix this it gives a two-lobed polar plot

Youssef Khmou on 4 Apr 2013
hi, its working if you define PI and E :
L=0.25;
A=L*pi;
lo=1;r=2;
k=2*pi;
E=1;
THETA=0:0.01:2*pi;
U =((cos(k/2*L.*cos(THETA))-cos(k/2*L))./sin(THETA)).^2*(E./(8.0*pi^2));
polar(THETA,U); % DIPOLE?