1、天线线列阵方向图天线线列阵方向图阵列方向图及MATLAB仿真1、线阵的方向图MATLAB程序如下(2元):clear;a=0:0.1:2*pi;y=sqrt(2+2*cos(pi-pi*cos(a);polar(a,y);图形如下:若阵元间距为半波长的M个阵元的输出用方向向量权重加以组合的话,阵列的方向图为MATLAB程序如下(10个阵元):clear;f=3e10;lamda=(3e8)/f;beta=2.*pi/lamda;n=10;t=0:0.01:2*pi;d=lamda/4;W=beta.*d.*cos(t);z1=(n/2).*W)-n/2*beta* d;z2=(1/2).*W)
2、-1/2*beta* d;F1=sin(z1)./(n.*sin(z2);iK1=abs(F1) ;polar(t,K1);方向图如下:2、圆阵方向图程序如下:clc; clear all; title(水平放置时的均匀圆阵方向图); % title(竖面放置时的均匀圆阵方向图); % 竖直放置 axis(0 90 0 180 -20 0); xlabel(俯仰角/(circ); ylabel(方位角/(circ); zlabel(P/dB); figure; contour(fi, theta, Y); 方向图如下:3、平面阵方向图:clc; clear all; close all; Ro
3、w_N = 16; % 行阵元数 Col_N = 16; % 列阵元数 k = 0.5; % k = d/lambda DOA_theta = 90; % 方位角 DOA_fi = 0; % 俯仰角 % 形成方位角为theta,俯仰角位fi的波束的权值 Row_n = 0 : Row_N-1; Col_n = 0 : Col_N-1; W_Row = exp(-j*2*pi*k*Row_n*cos(DOA_theta*pi/180)*cos(DOA_fi*pi/180); W_Col = exp(-j*2*pi*k*Col_n*sin(DOA_theta*pi/180)*cos(DOA_fi*
4、pi/180); % W_Col = exp(-j*2*pi*k*Col_n*sin(DOA_fi*pi/180); % 竖直放置 W_Row = chebwin(Row_N, 20) .* W_Row; % 行加切比雪夫权 W_Col = chebwin(Col_N, 30) .* W_Col; % 列加切比雪夫权 W = kron(W_Row, W_Col); % 合成的权值 N*N x 1 % 绘制水平面放置的平面阵的方向图 theta = linspace(0,180,180); fi = linspace(0,90,90); for i_theta = 1 : length(thet
5、a) for i_fi = 1 : length(fi) row_temp = exp(-j*2*pi*k*Row_n*cos(theta(i_theta)*pi/180)*cos(fi(i_fi)*pi/180); % 行导向矢量 N x 1 col_temp = exp(-j*2*pi*k*Col_n*sin(theta(i_theta)*pi/180)*cos(fi(i_fi)*pi/180); % 列导向矢量 N x 1 % col_temp = exp(-j*2*pi*k*Col_n*sin(fi(i_fi)*pi/180); % 竖直放置 Y(i_theta,i_fi) = W*k
6、ron(row_temp, col_temp); % 合成的导向矢量 N*N x 1 end end Y= abs(Y); Y = Y/max(max(Y); Y = 20*log10(Y); Y = (Y+60) .* (Y+60)0) - 60; % 切图 % Z = Y + 60; % Z = Z .* (Z 0); % Y = Z - 60; figure; mesh(fi, theta, Y); view(66, 33); title(水平面放置时的面阵方向图); axis(0 90 0 180 -60 0); xlabel(俯仰角/(circ); ylabel(方位角(circ);
7、 zlabel(P/dB); figure; contour(fi, theta, Y);方向图如下:4、CAPON方法波束形成MATLAB程序如下(阵元16,信号源3,快拍数1024):clear alli=sqrt(-1);j=i;M=16; %均匀线阵列数目P=3; %信号源数目f0=10;f1=50;f2=100;%信号频率nn=1024; %快拍数angle1=-15;angle2=15;angle3=30;%the signal angleth=angle1;angle2;angle3;SN1=10;SN2=10;SN3=10;%信噪比sn=SN1;SN2;SN3;degrad=p
8、i/180;tt=0:.001:1024;x0=exp(-j*2*pi*f0*tt); %3个信号x0、x1、x2x1=exp(-j*2*pi*f1*tt); %x2=exp(-j*2*pi*f2*tt); %t=1:nn;S=x0(t);x1(t);x2(t);nr=randn(M,nn);ni=randn(M,nn);u=nr+j*ni; %复高斯白噪声Ps=S*S./nn; %信号能量ps=diag(Ps);refp=2*10.(sn/10); tmp=sqrt(refp./ps);S2=diag(tmp)*S; %加入噪声tmp=-j*pi*sin(th*degrad);tmp2=0:M-1;a2=tmp2*tmp;A=exp(a2);X=A*S2+.1*u; %接收到的信号Rxx=X*X./nn; %相关矩阵invRxx=inv(Rxx);%搜寻信号th2=-90:90;tmp=-j*pi*sin(th2*degrad);tmp2=0:M-1;a2=tmp2*tmp;A2=exp(a2);den=A2*invRxx*A2;doa=1./den;semilogy(th2,doa,r);title(spectrum);xlabel(angle);ylabel(spectrum);axis(-90 90 1e1 1e5);grid;
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