i am new to matlab and getting matlab error .The error is Error using + Matrix dimensions must agree. Error in RL_Multilayered (line 30) n1=(Z0*tan​h(gamma1*d​1))+sqrt(1​/ebA);

clear all close all clc

load Mul.txt
d1=3e-3;            %%%%thickness
d2=3e-3;
d3=2e-3;
d4=2e-3;
f=(10^9)*Mul(:,1);         %%%%%frequency 
eb1a=Mul(:,2);%%%ebslon real part
eb1b=Mul(:,3);%%%ebslon imaginary part
ebA=complex(eb1a,-eb1b); %%%ebs complex

eb2a=Mul(:,4);%%%ebslon real part
eb2b=Mul(:,5);%%%ebslon imaginary part
ebB=complex(eb2a,-eb2b); %%%ebs complex

eb3a=Mul(:,6);%%%ebslon real part
eb3b=Mul(:,7);%%%ebslon imaginary part
ebC=complex(eb3a,-eb3b); %%%ebs complex

eb4a=Mul(:,8);%%%ebslon real part
eb4b=Mul(:,9);%%%ebslon imaginary part
ebD=complex(eb4a,-eb4b); %%%ebs complex

c=3*10^8;%%%speed of light
Z0=377;
j=sqrt(-1);
gamma1=2*pi*f*(1/c)*sqrt(1/ebA);%%%k1 imaginary
m1=sqrt(1/ebA)*tanh(gamma1*d1)+Z0;
n1=(Z0*tanh(gamma1*d1))+sqrt(1/ebA);
Z1=m1/n1;

gamma2=2*pi*f*(1/c)*sqrt(1/ebB);%%%k1 imaginary
m2=sqrt(1/ebB)*tanh(gamma2*d2)+Z1;
n2=(Z0*tanh(gamma2*d2))+sqrt(1/ebB);
Z2=m2/n2;

k3=1i*2*pi*f*(1/c).*sqrt(1.*ebC);%%%k3 imaginary
m2=Z2+Z0*sqrt(1./ebC).*tanh(k3*d3); %%%Layer 2
n2=Z0*sqrt(1./ebC)+Z2.*tanh(k3*d3); %%%Layer 2
Z3=(m2/n2)*Z0*sqrt(1./ebC);

k4=1i*2*pi*f*(1/c).*sqrt(1.*ebD);%%%k4 imaginary
m3=Z3+Z0*sqrt(1./ebD).*tanh(k4*d4); %%%Layer 2
n3=Z0*sqrt(1./ebD)+Z3.*tanh(k4*d4); %%%Layer 2
Z4=(m3/n3)*Z0*sqrt(1./ebD);
RL=20*log10(abs((Z2-Z0)/(Z2+Z0)));

figure(1)
subplot(211)
plot(f,real(Z2),'Linewidth',2),grid
ylabel('Real part z2')
subplot(212)
plot(f,imag(Z2),'Linewidth',2),grid,shg
xlabel('Frequency HZ')
ylabel('Imaginary part z2')

figure(2)
plot(f,RL,'Linewidth',2),grid
ylabel('RL')
xlabel('Frequency HZ')

[ezhar Haq]

sir now the same occur in line 41 i.e Error using / Matrix dimensions must agree.

Error in Untitled3 (line 41) Z3=(m2/n2)*Z0*sqrt(1./ebC);

[Geoff Hayes]

If you put a breakpoint at this line and run your script, the debugger will pause at this line. What are the dimensions of m2 and n2? Do you really mean to divide one matrix by the other or do you mean to do an element-wise division in which case you should have

 Z3=(m2./n2)*Z0*sqrt(1./ebC);

Note that the above might not fix the problem because then the multiplication may fail. Please describe the dimensions for each of the variables used in this equation.

[Geoff Hayes]

Discussion for this problem is at http://www.mathworks.com/matlabcentral/answers/262915-plz-someone-give-me-the-sample-solution-to-my-problem-in-my-matlab-code-in-code-the-error-occur-i-e.

Answer 1

[Geoff Hayes]

ezhar - try using the MATLAB debugger to troubleshoot what the problem might be. If you put a breakpoint at the line

 n1=(Z0*tanh(gamma1*d1))+sqrt(1/ebA);

and then run your script, you will notice that gamma1 is an mxm matrix and sqrt(1/eba) is a 1xm matrix (where m is the number of rows in Mul). Since the code is trying to add two matrices of different dimensions, then the error message makes sense. What are you expecting to happen at this line of code?

Note that your frequency f is a column vector too which then makes gamma1 an mxm. Is this correct?