3-D plot in matlab

Hey..I'm trying to plot the following code but i keep getting this error: (??? Error using ==> surf at 78 Z must be a matrix, not a scalar or vector.)

%% Defining givens:

f= 300e6; %% Chosen frequency

c= 3e8; %% Free space

lambda= c./f; %% Wavelenght

l_2=lambda./2;

k= (2.*pi)./l_2; %% Wave number

Io=5; % Chosen maximum value of the current

eighta=377; % Intrinsic impedance (free space)

r=l_2/(2.*pi); % Distance

h= 0:1:100; %% Variable height from the ground

L=1.25*l_2; % Dipole length

theta= 2*pi; %% Computing the requirements:

%% Electric field:

 A= (k.*L.*Io.*exp(-1i.*r.*k))./(4.*pi.*r);

 B= 2.*(cos(cos(theta).*k.*h));

E_F= eighta.*1i.*(A).*sin(theta).*(B);

[x,y,z]=sph2cart(h,theta-pi/2,E_F); % Converting to cartesian coordinates

% Generating 3D plot

surf(x,y,z) % Generating 3D plot

colormap(JET);

title ('Electric Field in 3D plot')

legend ('Heigth','Theta','Electric Field')

rotate3D on

axis image

Help!!

Answer 1

[Azzi Abdelmalek]

You can't use surf. Use

plot3(abs(x),abs(y),abs(z)) % Generating 3D plot

[A A]

hey Azzi, thanks for your fast reply but when I used the command you gave me..it only resulted in a plot of one straight line and not 3D :(..do you have anything else to help me with??

Answer 2

[Wara Qasim]

hello please help me with this code i m trying to plot 3d figure of electric field but when i use plot3 i get error "Data cannot have more than 2 dimensions" and when i use quiver3 i get error that Z and U must be of same size. although sizes of all the matrices is same please help

clear all;

clc;

k = 9*10^9;

% Enter the Relative permittivity

eps_r = 1;

charge_order = 10^-9; % milli, micro, nano etc..

const = k*charge_order/eps_r;

x = 0:2:6;

y = 0:1:6;

z = 0:3:6;

[X,Y,Z]=meshgrid(x,y,z)

Y1=size(Y)

X1=size(X)

Z1=size(Z)

% Enter the dimensions

Nx=7;

Ny=4;

Nz=3;

% Enter the number of charges.

n = 2;

% Electric fields Initialization

E_f = zeros(Nx,Ny,Nz);

Ex = E_f;

Ey = E_f;

Ez = E_f;

% Vectors initialization

ex = E_f;

ey = E_f;

ez= E_f;

r = E_f;

r_square = E_f;

% Array of charges

Q = [2,-2];

% Array of locations

Z = [5,-5];

Y = [0,0];

X=[0,0];

%-------------------------------------------------------------------------%

% COMPUTATION OF ELECTRIC FIELDS

%-------------------------------------------------------------------------%

% Repeat for all the 'n' charges

for l = 1:n

q = Q(l);

% Compute the unit vectors

for i=1:Nx

for j=1:Ny

for k=1:Nz

r_square(i,j,k) = (i-51-X(l))^2+(j-51-Y(l))^2+(k-51-Z(l))^2;

r(i,j,k) = sqrt(r_square(i,j,k));

ex(i,j,k) = ex(i,j,k)+(i-51-X(l))./r(i,j,k);

ey(i,j,k) = ey(i,j,k)+(j-51-Y(l))./r(i,j,k);

ez(i,j,k) = ez(i,j,k)+(j-51-Z(l))./r(i,j,k);

end

end

end

E_f = E_f + q.*const./r_square;

Ex = Ez + E_f.*ex.*const;

Ey = Ez + E_f.*ey.*const;

Ez = Ez + E_f.*ez.*const;

end

e1=size(Ex)

e2=size(Ey)

e3=size(Ez)

plot3(abs(Ex),abs(Ey),abs(Ez))

%quiver3(X,Y,Z,Ex,Ey,Ez,'r');

%axis square;