均匀圆阵方向图.m

matlab,线阵

%  绘制水平面放置的均匀圆阵的方向图 P35 图2.4.4(a)
clc; 
clear all； 
close all;

M = 16; % 行阵元数
k = 0.8090;    % k = r/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
m = [0 : M-1];
w = exp(-j*2*pi*k*cos(2*pi*m'/M-DOA_theta*pi/180)*cos(DOA_fi*pi/180)); 
% w = exp(-j*2*pi*k*(cos(2*pi*m'/M)*cos(DOA_theta*pi/180)*cos(DOA_fi*pi/180)+sin(2*pi*m'/M)*sin(DOA_fi*pi/180)));   % 竖直放置
% w = chebwin(M, 20) .* w;    % 行加切比雪夫权

% 绘制水平面放置的均匀圆阵的方向图
theta = linspace(0,180,360);
fi = linspace(0,90,180);
for i_theta = 1 : length(theta) 
    for i_fi = 1 : length(fi) 
        a = exp(-j*2*pi*k*cos(2*pi*m'/M-theta(i_theta)*pi/180)*cos(fi(i_fi)*pi/180)); 
%         a = exp(-j*2*pi*k*(cos(2*pi*m'/M)*cos(theta(i_theta)*pi/180)*cos(fi(i_fi)*pi/180)+sin(2*pi*m'/M)*sin(fi(i_fi)*pi/180))); % 竖直放置
        Y(i_theta,i_fi) = w'*a;
    end
end

Y= abs(Y); Y = Y/max(max(Y));
Y = 20*log10(Y);
% Y = (Y+20) .* ((Y+20)>0) - 20;  % 切图
Z = Y + 20;
Z = Z .* (Z > 0);
Y = Z - 20;
figure;     mesh(fi, theta, Y);     view([66, 33]);
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);