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//Chapter 12: The Cylindrical Antenna and the Moment Method
//Example 12-12.1
clc;
//Variable Initialization
N = 3 //Piecewise sinusoidal dipole modes (unitless)
l = 1/10.0 //Dipole length (lambda)
z11_exact = 0.4935 - 3454*%i //Exact impedance vector(ohm)
z11_apprx = 0.4944 - 3426*%i //Approximate impedance vector(ohm)
z12_exact = 0.4935 + 1753*%i //Exact impedance vector(ohm)
z12_apprx = 0.4945 + 1576*%i //Approximate impedance vector(ohm)
z13_exact = 0.4935 + 129.9*%i //Exact impedance vector(ohm)
z13_apprx = 0.4885 + 132.2*%i //Approximate impedance vector(ohm)
//Calculations
N2 = N + 1 //Number of equal segments (unitless)
d = l/4 //Length of each segment (lambda)
Rmn = 20*(2*%pi*d)**2 //Real part of elements of Z-matrix, Zmn (VA)
zmat_apprx=([z11_apprx+z13_apprx,z12_apprx;2*z12_apprx,z11_apprx])//matrix(unitless)
vmat = ([0;1]) //Voltage matrix (unitless)
[i1]=linsolve(zmat_apprx,vmat) //Current matrix (unitless)
i1=i1*-1
i_ratio = i1(2)/i1(1) //Current ratio (unitless)
zin = vmat(2)/i1(2) //Input impedance (ohm)
zmat_exact =([z11_exact+z13_exact,z12_exact;2*z12_exact,z11_exact])
[i1_e] = linsolve(zmat_exact,vmat) //Current matrix (unitless)
i1_e=i1_e*-1
i_ratio_exact = i1_e(2)/i1_e(1) //Current ratio (unitless)
zin_exact = vmat(2)/i1_e(2) //Input impedance (ohm)
//Result
mprintf("The current ratio is %.2f+%.4f j",real(i_ratio),imag(i_ratio))
mprintf("\nThis is nearly equal to 1.9 indicating a nearly triangular current distribution")
mprintf("\nThe input impedance is %.3f%.3fj ohm using approximate values", real(zin),imag(zin))
mprintf("\nThe input impedance is %.3f%.3fj ohm using exact values", real(zin_exact),imag(zin_exact))
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