矩量法分析八木天线.docx
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矩量法分析八木天线
矩量法分析八木天线
如何用基于hallen方程的MoM分析八木天线,
clear
lamda=1;
a=0.0025;
me=8.85e-12;
mu=4*pi*(1e-7);arg=2*pi*(3e8)/lamda;k=2*pi/lamda;
L1=0.499*lamda;%为什么取0.499而不是0.5L2=0.460*lamda;L3=0.419*lamda;d=0.20*lamda;
N1=59;
N2=59;
N3=59;
dL1=L1/(N1+1);
dL2=L2/(N2+1);
dL3=L3/(N3+1);
lz1=-L1/2:
dL1:
L1/2;lzm1=lz1(2:
N1+1);lz2=-L2/2:
dL2:
L2/2;lzm2=lz2(2:
N2+1);lz3=-L3/2:
dL3:
L3/2;lzm3=lz3(2:
N3+1);M=N1+N2+N3;
forkm=1:
M
ifkm<=N1
A(km).y=-d;
A(km).z=lzm1(km);
elseif(km<=N1+N2)&(km>N1)
A(km).y=0;
A(km).z=lzm2(km-N1);
else
A(km).y=d;
A(km).z=lzm3(km-N1-N2);
end
end
form=1:
M
ifm<=N1
flagm=1;
Vim=0;
hm.y=-d;
hm.z=L1/2;
elseifm<=N1+N2
flagm=2;
Vim=1;
hm.y=0;
hm.z=L2/2;
else
flagm=3;
Vim=0;
hm.y=d;
hm.z=L3/2;
end
forn=1:
M
ifn<=N1
flagn=1;
dL=dL1;
elseifn<=N1+N2
flagn=2;
dL=dL2;
else
flagn=3;
dL=dL3;
end
ifm==n
Rhmn=sqrt((hm.z-A(n).z)^2+a^2);
Fmn=(1/(2*pi))*log(dL/a)-j*k*dL/(4*pi);
Fhmn=exp(-j*k*Rhmn)/(4*pi*Rhmn)*dL;
else
ifflagm==flagn
Rhmn=sqrt((hm.z-A(n).z)^2+a^2);
Rmn=sqrt((A(m).z-A(n).z)^2+a^2);
else
Rhmn=sqrt((hm.y-A(n).y)^2+(hm.z-A(n).z)^2);
Rmn=sqrt((A(m).y-A(n).y)^2+(A(m).z-A(n).z)^2);
end
Fhmn=exp(-j*k*Rhmn)/(4*pi*Rhmn)*dL;
Fmn=exp(-j*k*Rmn)/(4*pi*Rmn)*dL;
end
Z(m,n)=cos(k*hm.z)*Fmn-cos(k*A(m).z)*Fhmn;
end
V(m,1)=j*Vim*sin(k*(hm.z-abs(A(m).z)))/(2*120*pi);end
I=linsolve(Z,V);
figure
(1)
plot(abs(I),'m:
','linewidth',2)
fedp=N1+(N2+1)/2;
Zin=1/I(fedp)
gridon
theta=0:
pi/100:
2*pi;%画E面方向图
pha=pi/2;
form=1:
length(theta)
F(m)=0;
forn=1:
M
ifn<=N1
dL=dL1;
elseifn>N1&n<=N1+N2
dL=dL2;
else
dL=dL3;
end
F(m)=F(m)+I(n)*exp(j*k*(A(n).y*sin(theta(m))*sin(pha)+A(n).z*cos(theta(m))))*dL*(-sin(theta
(m)));
end
end
F=abs(F);
F1=F/max(F);
figure
(2)
polar(theta,F1,'mo')FBR=20*log10(F(51)/F(151));
theta=pi/2;%画H面方向图
pha=0:
pi/100:
2*pi;
form=1:
length(pha)
F11(m)=0;
forn=1:
M
ifn<=N1
dL=dL1;
elseifn>N1&n<=N1+N2
dL=dL2;
else
dL=dL3;
end
F11(m)=F11(m)+I(n)*exp(j*k*(A(n).y*sin(theta)*sin(pha(m))+A(n).z*cos(theta)))*dL*(-sin(thet
a));
end
end
F21=abs(F11);%方向图函数
F21=F21/max(F21);%归一化方向图函数
figure(3)
polar(pha,F21,'mo');
Rin=real(Zin);
G=(1/(480*pi^2))*arg^2*mu^2*max(F)^2/(Rin*abs(I(fedp))^2);
T=(Zin-50)/(Zin+50);SWR=(1+abs(T))/(1-abs(T));谢谢哦~~我已经知道了。
那个如果反射线取0.500,会产生奇点的。
矩量法分析八木天线
clear
lamda=1;%波长
a=0.0025;%振子的半径
me=8.85e-12;%介电常数
mu=4*pi*(1e-7);%磁导率
arg=2*pi*(3e8)/lamda;%角频率
k=2*pi/lamda;%波数
N2=51;
L1=0.5*lamda;
L2=0.460*lamda;
L3=0.419*lamda;
d=0.2*lamda;
dL=L2/(N2+1);
N1=fix(L1/dL);
dL1=rem(L1,dL);
N3=fix(L3/dL);
dL3=rem(L3,dL);
l1=L1/2-dL1/2;
l2=L2/2-dL/2;
l3=L3/2-dL3/2;
lzintal1=-l1:
dL:
l1;
lzm1=lzintal1(1:
N1)+dL/2;
lzintal2=-l2:
dL:
l2;
lzm2=lzintal2(1:
N2)+dL/2;
lzintal3=-l3:
dL:
l3;
lzm3=lzintal3(1:
N3)+dL/2;
M=N1+N2+N3;
forkm=1:
M
ifkm<=N1
A(km).y=-d;
A(km).z=lzm1(km);
elseifkm<=N1+N2
A(km).y=0;
A(km).z=lzm2(km-N1);
else
A(km).y=d;
A(km).z=lzm3(km-N1-N2);
end
end
form=1:
M
forn=1:
M
ifn==m
Fmnmm=(1/(2*pi*dL))*log(dL/a)-j*k/(4*pi);
Fmnee=(1/(2*pi*dL))*log(dL/a)-j*k/(4*pi);
Fmnss=(1/(2*pi*dL))*log(dL/a)-j*k/(4*pi);
Fmnse=exp(-j*k*dL)/(4*pi*dL);
Fmnes=exp(-j*k*dL)/(4*pi*dL);
elseifabs(n-m)==1
Rmm=sqrt((A(m).y-A(n).y)^2+(A(m).z-A(n).z)^2);
Fmnmm=exp(-j*k*Rmm)/(4*pi*Rmm);
Fmnee=exp(-j*k*Rmm)/(4*pi*Rmm);
Fmnss=exp(-j*k*Rmm)/(4*pi*Rmm);
ifmRmnse=sqrt((A(m).y-A(n).y)^2+((A(m).z-dL/2)-(A(n).z+dL/2))^2);
Fmnse=exp(-j*k*Rmnse)/(4*pi*Rmnse);
if(m==N1)||(m==N1+N2)
Rmnes=sqrt((A(m).y-A(n).y)^2+((A(m).z+dL/2)-(A(n).z-dL/2))^2);
Fmnes=exp(-j*k*Rmnes)/(4*pi*Rmnes);
else
Fmnes=(1/(2*pi*dL))*log(dL/a)-j*k/(4*pi);
end
elseifm>n
Rmnes=sqrt((A(m).y-A(n).y)^2+((A(m).z+dL/2)-(A(n).z-dL/2))^2);
Fmnes=exp(-j*k*Rmnes)/(4*pi*Rmnes);
if(n==N1)||(n==N1+N2)
Rmnse=sqrt((A(m).y-A(n).y)^2+((A(m).z-dL/2)-(A(n).z+dL/2))^2);
Fmnse=exp(-j*k*Rmnse)/(4*pi*Rmnse);
else
Fmnse=(1/(2*pi*dL))*log(dL/a)-j*k/(4*pi);
end
end
else
Rmm=sqrt((A(m).y-A(n).y)^2+(A(m).z-A(n).z)^2);
Rmnse=sqrt((A(m).y-A(n).y)^2+((A(m).z-dL/2)-(A(n).z+dL/2))^2);
Rmnes=sqrt((A(m).y-A(n).y)^2+((A(m).z+dL/2)-(A(n).z-dL/2))^2);
Fmnmm=exp(-j*k*Rmm)/(4*pi*Rmm);
Fmnee=exp(-j*k*Rmm)/(4*pi*Rmm);
Fmnss=exp(-j*k*Rmm)/(4*pi*Rmm);
Fmnse=exp(-j*k*Rmnse)/(4*pi*Rmnse);
Fmnes=exp(-j*k*Rmnes)/(4*pi*Rmnes);
end
z(m,n)=j*arg*mu*dL*dL*Fmnmm+(1/(j*arg*me))*(Fmnee-Fmnes-Fmnse+Fmnss);
end
end
V=zeros(M,1);
fedp=N1+(N2+1)/2;%馈电点的位置
V(fedp)=1*dL;%馈电的电位
I=linsolve(z,V);
Zin=V(fedp)/I(fedp)%输入阻抗
I1=abs(I);
plot(I1);gridon