【天线阻抗】基于matlab耦合偶极子天线阻抗计算【含Matlab源码 7447期】.zip

% Impedance of coupled dipole antenna with respect to wavelength.The dipole antenna seperated by distance % delta. The method used is Hallen's Integral. Here the second dipole is not fed by any % voltage source clear all; lamda=1; %arbitary wavelength (in meter): this can be varied accourding to the problem l=0.5*lamda; % length of dipole: this can be varied accourding to the problem a=0.001*lamda; % radius of dipole: this can be varied accourding to the problem N=50; % no.of segments i.e. the sampling points in antenna surface/for convergence: this can be varied accourding to the problem dz=l/(2*(N-1/2));% incremental length of l/2 upper part of antenna z=dz/2:dz:dz*(N); % stores the invremental length in upper part of antenna k=2*pi/lamda; % wave number etta=377; % free space impedance V_impressed=-1; % impressed voltage on D1: this can be varied accourding to the problem delta=0.1*lamda:0.1:5*lamda; % distance between the dipoles for d=1:length(delta) %%%%%% calculating the Green's Function on first dipole (with source)%%%%% %%%%%%%%%%%%%%%%calculating Function's due to current in first and second dipole%%%%%%%% for m=1:N %m is the obsevation point for n=1:N-1% n is the source points R1=sqrt(a^2+(z(m)-z(n))^2); % R+ in lecture notes for G11 R2=sqrt(a^2+(z(m)+z(n))^2); % R- in lecture notes for G11 R3=sqrt(delta(d)^2+(z(m)-z(n))^2); % R+ for G12 R4=sqrt(delta(d)^2+(z(m)+z(n))^2); % R- for G12 %%%%%%%%%%%%% evaluating greens function G11 %%%%%%%%%%%%%%%% G1=exp(-j*k*R1)/(4*pi*R1); % G11(R+) in lecture notes G2=exp(-j*k*R2)/(4*pi*R2); % G11(R-) in lecture notes G_11(m,n)=(G1+G2)*dz; % G11(R) observation in D1 source:1 %%%%%%%%%%%%% evaluating greens function G12 %%%%%%%%%%%%%% G3=exp(-j*k*R3)/(4*pi*R3); % G12(R+) in lecture notes G4=exp(-j*k*R4)/(4*pi*R4); % G12 (R-)in lecture notes G_12(m,n)=(G3+G4)*dz; % G12(R) observation in D1 source:2 end v_1(m)=j/(2*etta)*(sin(k*z(m))); % Sine term due to impressed voltage in D1 end %%%%%% calculating the Green's Function on second dipole (without source)%%%%% %%%%%%%%%%%%%%%%calculating Function's due to current in first and second dipole%%%%%%%% for m=1:N %m is the obsevation point for n=1:N-1% n is the source points R5=sqrt(a^2+(z(m)-z(n))^2); % R+ in lecture notes for G22 R6=sqrt(a^2+(z(m)+z(n))^2); % R- in lecture notes for G22 R7=sqrt(delta(d)^2+(z(m)-z(n))^2); % R+ for G21 R8=sqrt(delta(d)^2+(z(m)+z(n))^2); % R- for G21 %%%%%%%%%%%%% evaluating greens function G22 %%%%%%%%%%%%%% G5=exp(-j*k*R5)/(4*pi*R5); % G22(R+) in lecture notes G6=exp(-j*k*R6)/(4*pi*R6); % G22(R-) in lecture notes G_22(m,n)=(G5+G6)*dz; % G22(R) observation in D2 source:2 %%%%%%%%%%%%% evaluating greens function G12 %%%%%%%%%%%%%% G7=exp(-j*k*R7)/(4*pi*R7); % G21(R+) in lecture notes G8=exp(-j*k*R8)/(4*pi*R8); % G21 (R-)in lecture notes G_21(m,n)=(G7+G8)*dz; % G21(R) observation in D2 source:1 end v_2(m)=0; % Sine term due to impressed voltage in D2 (no voltage applied in D2) end %%%%%%%%%%%% concatenating G11 and G12%%%%%%%%%%% G_D1=horzcat(G_11,G_12); s=size(G_D1); N_t1=s(2); G_D1(:,N_t1+1)=[-cos(k*z)]; % N element holds the cosine terms for D1 G_D1(:,N_t1+2)=[0]; % N+1 element holds the cosine terms for D2 which is zero for D1 %%%%%%%%%%%% concatenating G21 and G22%%%%%%%%%%% G_D2=horzcat(G_21,G_22); s_1=size(G_D2); N_t2=s_1(2); G_D2(:,N_t2+1)=[0]; % N element holds the cosine terms from D1 which is zero for D1 G_D2(:,N_t2+2)=[-cos(k*z)]; % N+1 element holds the cosine terms from D2 %%%%%%%%%%%%%concatenating Sine terms i.e. Vm%%%%%%%%%%%%% Vm=horzcat(v_1,v_2); %%% Defining the matrix required to evaluate the current%%%%%%%% G_eval=vertcat(G_D1,G_D2); %%%% evaluate current%%% I=inv(G_eval)*Vm.'; % this will give a column vector of current %%%%%%%%%%% for question number 4 (LAB part)%%%%%%%%%%%%%%%%%%%% s_2= size(I); N_t3=s_2(1); % this will give the number of elements in column N1=(N_t3-2)/2; I1=I(1); % first element gives the current in the centre of D1 I2=I(N1+1); % this gives the current in the centre of D2 Z_11(d)=V_impressed/I1; Z_12(d)=V_impressed/I2; end plot(delta,real(Z_11)); hold on plot(delta,imag(Z_11),'r') legend('real-Z11','Imaginary-Z11') title('阻抗的实部和虚部') xlabel('delta'); ylabel('阻抗') grid on figure plot (delta, real(Z_12),'b:<') hold on plot (delta,imag(Z_12),'r-->') legend('real-Z12','Imaginary-Z12') title('阻抗的实部和虚部') xlabel('delta'); ylabel('阻抗') grid on