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Example 3.3 Beam pattern of continuous linear array in different viewing directions
Example 3.3 Beam pattern of continuous linear array in different viewing directions
Considering a continuous linear array with a length of , examine the beam pattern
when the beam observation direction is taken separately .
Use the following formula
The calculation uses uniform weighting and the beam response after pointing adjustment. The results are shown in the following figure. The logarithm of the beam pattern shown therein represents the result.
It can be seen from the figure that the main lobes of the obtained beams all point to the desired beam observation direction, and the beam pattern is symmetrical with respect to the linear array. With the beam viewing angle 0. From the horizontal direction of the linear array to the end-fire direction, the width of the main lobe of the beam gradually widens. In the beam shown in the figure, the 60° azimuth is connected to the main lobe of the 120° azimuth beam.
figure 1
figure 2
image 3
Figure 4
f=1000; %频率
c=340; %声速
lambda = c/f;
space=0.04; %麦克风间距
L=5*lambda; %连续阵间距
theta_angle=0:0.1:360;
theta=theta_angle*pi/180;
theta_d = [0 30 60 90] *pi./180; %入射角度
for i = 1:length(theta_d)
thet = theta_d(i);
B=sin(pi*L/lambda*(cos(theta)-cos(thet)))./(pi*L/lambda*(cos(theta)-cos(thet)));
B_db=20*log10(B);
index = B_db < -50;
B_db(index) = -50;
figure;
polar(theta,50+B_db);
title_txt = [num2str(thet*180/pi)];
title(['\phi_o=' title_txt '^\circ']);
end
Edited on 10-20