低旁瓣微带天线设计MATLAB程序
2017-07-08 20:29阅读：
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设计一个切比雪夫微带天线阵，阵元数目为10x6，实现低旁瓣辐射。
设计参数要求：
工作频率：10GHz
天线单元间距：一个波长
水平方向旁瓣电平：-30dB
垂直方向旁瓣电平：-30dB
Chebyshev阵的电流分布已知。
function Microstrip
%该程序用来设计低旁瓣微带天线，并绘制E面与H面方向图
clear
close all
freq=10e9;
c0=3e8;
lamda=c0/freq;
a=8.7e-3; %mm-m
% b=8.53e-3; %mm-m
%%天线单元方向图
theta=linspace(-pi/2,pi/2,400);
% fee=zeros(size(theta));
% feh=zeros(size(theta));
% for i=1:length(theta)
%
u=sqrt(2.0)*pi*a*sin(theta(i))/lamda;
%
fee(i)=sin(u)*(1+u^2/(u^2-pi^2))/u;
%
feh(i)=sin(u)*(1-u^2/(u^2-pi^2))*cos(theta(i))/u;
% end
u1=sqrt(2.0)*pi*a*sin(theta)/lamda;
fee=sin(u1).*(1+u1.^2./(u1.^2-pi^2))./u1;
%E面方向图
feh=sin(u1).*(1-u1.^2./(u1.^2-pi^2)).*cos(theta)./u1;
%H面方向图
feh=feh/max(abs(feh));
fee=fee/max(abs(fee));
figure
h1=polar(theta,abs(feh));
set(h1,'linewidth',2)
title('微带天线单元H面方向图')
figure
h2=polar(theta,abs(fee));
set(h2,'linewidth',2)
title('微带天线单元E面方向图')
figure
h1=plot(r2d(theta),20*log10(abs(feh)));
set(h1,'linewidth',2)
axis([-90 90 -50 30])
xlabel('俯仰角/°')
ylabel('增益/dB')
title('微带天线单元H面方向图')
figure
h2=plot(r2d(theta),20*log10(abs(fee)));
set(h2,'linewidth',2)
axis([-90 90 -50 30])
xlabel('俯仰角/°')
ylabel('增益/dB')
title('微带天线单元E面方向图')
N=10;
In=[1 0.878 0.669 0.43 0.258];
%水平线阵电流分布
M=6;
Im=[1 0.9275 0.5012];
%垂直线阵电流分布
db=-30;
R0=10^(-db/20);
a0N=0.5*((R0+sqrt(R0^2-1))^(1.0/(N-1))+(R0+sqrt(R0^2-1))^(-1.0/(N-1)));
a0M=0.5*((R0+sqrt(R0^2-1))^(1.0/(M-1))+(R0+sqrt(R0^2-1))^(-1.0/(M-1)));
x=cos(pi*sin(theta));
faN=zeros(size(x));
faM=zeros(size(x));
N2=floor(N/2);
M2=floor(M/2);
for i=1:length(x)
%天线阵阵因子
xt=x(i);
for j=1:N2
faN(i)=faN(i)+2*In(j)*fun_chebyshev(2*j-1,xt);
end
for j=1:M2
faM(i)=faM(i)+2*Im(j)*fun_chebyshev(2*j-1,xt);
end
end
% for i=1:length(x)
% xt=x(i);
%
faN(i)=2*fun_chebyshev(N-1,a0N*xt);
%
faM(i)=2*fun_chebyshev(M-1,a0M*xt);
% end
fh=feh.*faN;
%阵因子与单元方向图相乘
fe=fee.*faM;
figure
h1=plot(r2d(theta),20*log10(abs(faN)));
set(h1,'linewidth',2)
axis([-60 60 -50 30])
xlabel('俯仰角/°')
ylabel('增益/dB')
title('微带天线水平线阵阵因子（H）')
figure
h2=plot(r2d(theta),20*log10(abs(faM)));
set(h2,'linewidth',2)
axis([-60 60 -50 30])
xlabel('俯仰角/°')
ylabel('增益/dB')
title('微带天线垂直线阵阵因子（E）')
figure
% h1=polar(theta,abs(fh));
h1=plot(r2d(theta),20*log10(abs(fh)));
set(h1,'linewidth',2)
axis([-60 60 -50 30])
xlabel('俯仰角/°')
ylabel('增益/dB')
title('微带天线H面方向图')
figure
% h2=polar(theta,abs(fee));
h2=plot(r2d(theta),20*log10(abs(fe)));
set(h2,'linewidth',2)
axis([-60 60 -50 30])
xlabel('俯仰角/°')
ylabel('增益/dB')
title('微带天线E面方向图')
function Tnx=fun_chebyshev(n,x)
%切比雪夫多项式函数
if(n==1)
Tnx=x;
elseif(n==2)
Tnx=2*x^2-1;
else
Tnx=2*x*fun_chebyshev(n-1,x)-fun_chebyshev(n-2,x);
end
