%Vertical Radiation Pattern for an Array of Linear Antenas

clear all

lambda=10; %m
k=2*pi/lambda; %wavenumber
RP=100; %m - distance from origin (observation point)
C=j*60/RP*exp(-j*k*RP)/RP; %constant

%ANTENNAS POSITIONS AND FEED
rp=[lambda/8 lambda/8];
phip=[-pi/2 pi/2];
z=[0 0];

%ANTENNAS LENGTHS
L=[lambda/2 lambda/2];

l=L/2; %half-length of antennas

%CURRENT
I0=[1 exp(j*pi/2)];

%RESOLUTION
Rez=100; %angle resolution=pi/Rez
theta=linspace(eps,pi-eps,Rez);
phi1=pi/2;
phi2=phi1+pi;

E1=zeros(1,length(theta)); %to be populated

for th=1:length(theta),
    A1=rp*sin(theta(th)).*cos(phi1-phip)+z*cos(theta(th));
    A2=exp(j*k*A1);
    B1=cos(k*l*cos(theta(th)))-cos(k*l);
    B2=B1/sin(theta(th));
    EE=C*I0.*A2.*B2;
    E11=sum(EE);
    E1(th)=E11;
end

E2=zeros(1,length(theta)); %to be populated

for th=1:length(theta),
    A1=rp*sin(theta(th)).*cos(phi2-phip)+z*cos(theta(th));
    A2=exp(j*k*A1);
    B1=cos(k*l*cos(theta(th)))-cos(k*l);
    B2=B1/sin(theta(th));
    EE=C*I0.*A2.*B2;
    E12=sum(EE);
    E2(th)=E12;
end

E=[E1 E2]; %for normalization
AE=abs(E); %amplitude
AEM=max(AE); %maximum of the amplitudes
RE1=abs(E1)/AEM; %for phi1
RE2=abs(E2)/AEM; %for phi2

%representation angles(plots)
phirep1=pi/2-theta; %for phi1
phirep2=theta+pi/2; %for phi2

figure(3)
polar(phirep2,RE2)
hold
polar(phirep1,RE1)
hold
title('Vertical radiation pattern')