Question

By using MATLAB software:

Exercise 2: Generate radiation pattern for a dipole as its length varies.

% M-File: ML0803

%

% Dipole antenna movie shows radiation

% pattern as dipole length grows from 0.1

% lambda to 2.1 lambda.

%

% Variables

% L dipole length (in wavelengths)

% bL2 phase constant * length/2

% N number of theta points

% th,thr angle theta in degrees,radians

% num,den temporary variables

% F un-normalized power function

clc %clears the command window

clear %clears variables

% Initialize variables

N=360;

th=1:1:N;

thr=th*pi./180;

% Generate Reference Frame

L=0.1;

polar(0,6); %sets scale for polar plot

T=num2str(L);

S=strvcat('Length',T,'wavelengths');

text(6,6,S)

axis manual

title('Linear Antenna Radiation Pattern')

hold on

pause

% Make the Movie

L=0.1:0.02:2.1;

for n=1:100

polar(0,6)

axis manual

title('Linear Antenna Radiation Pattern')

T=num2str(L(n));

S=strvcat('Length',T,'wavelengths');

text(6,6,S)

hold on

num=cos(pi*L(n)*cos(thr))-cos(pi*L(n));

den=sin(thr);

F=(num./den).^2;

polar(thr,F)

hold off

M(:,1)=getframe;

end

Question 2: Run this program for different choices of dipole length.

Answer 1

The code for this problem is already given above.

MATLAB Code ==>

% Dipole antenna movie shows radiation

% pattern as dipole length grows from 0.1

% lambda to 2.1 lambda.

%

% Variables

% L dipole length (in wavelengths)

% bL2 phase constant * length/2

% N number of theta points

% th,thr angle theta in degrees,radians

% num,den temporary variables

% F un-normalized power function

clc %clears the command window

clear %clears variables

% Initialize variables

N=360;

th=1:1:N;

thr=th*pi./180;

% Generate Reference Frame

L=0.1;

polar(0,6); %sets scale for polar plot

T=num2str(L);

S=strvcat('Length',T,'wavelengths');

text(6,6,S)

axis manual

title('Linear Antenna Radiation Pattern')

hold on

pause

% Make the Movie

L=0.1:0.02:2.1;

for n=1:1

polar(0,6)

axis manual

title('Linear Antenna Radiation Pattern')

T=num2str(L(n));

S=strvcat('Length',T,'wavelengths');

text(6,6,S)

hold on

num=cos(pi*L(n)*cos(thr))-cos(pi*L(n));

den=sin(thr);

F=(num./den).^2;

polar(thr,F)

hold off

M(:,1)=getframe;

end

RESULTS ==>

Its result is an animation. I am sending you the snapshots below ==>

NOTE - If you have any issue with the solution, then please ask me in the comments.