In ULA monopulse, i can't find sum beam and difference beam

 clc; clear all; close all;

 % Transmitted signal

 f = 3e8; %[Hz]
 c = 3e8;
 lambda = c/f;
 N = 10; %number of element
 theta = -89:0.05:89;
 theta_0 = 0;
 d = lambda / 2;
 Nx = 10;
 theta_steering = 5; % steering 각도 +-5

 at = exp(1j*2*(0:N-1)'*pi*d/lambda*sind((theta)/2));
 w_left = exp(-1j*2*(0:N-1)'*pi*d/lambda*sind((theta_0)-(theta_steering)));
 w_right = exp(-1j*2*(0:N-1)'*pi*d/lambda*sind((theta_0)+(theta_steering)));
  
 Beam_left = w_left.*exp(1j*2*(0:N-1)'*pi*d/lambda*sind((theta)));
 Beam_right = w_right.*exp(1j*2*(0:N-1)'*pi*d/lambda*sind((theta)));

 Beam_left2 = sum(Beam_left,1);
 Beam_left3 = abs(Beam_left2/max(Beam_left2));

 Beam_right2 = sum(Beam_right,1);
 Beam_right3 = abs(Beam_right2/max(Beam_right2));

 figure(2)
 plot(theta,20*log10((Beam_left3)))
 hold on 
 plot(theta,20*log10((Beam_right3)))
 xlim([-90 90])
 ylim([-50 0])
 xlabel("\theta")
 grid on
 xlabel("\theta")
 ylabel("Normalized Pattern [dB]")
 title("left beam and right beam of amplitude comparison monopulse")
 legend('left beam','right beam')

 
 %% sum & difference

 w_sum = w_left + w_right;
 w_diff = w_left - w_right;
    
 Beam_sum = Beam_left + Beam_right;
 Beam_sum2 = sum(Beam_sum, 1);
 Beam_sum3 = abs(Beam_sum2/max(Beam_sum2));
 
 Beam_diff = Beam_left - Beam_right;
 Beam_diff2 = sum(Beam_diff,1);
 Beam_diff3 = abs(Beam_diff2/max(Beam_diff2));

 figure(3)
 plot(theta,20*log10((Beam_sum3)))       
 hold on
 plot(theta,20*log10((Beam_diff3)))
 xlim([-90 90])
 ylim([-30 0])
 xlabel("\theta")
 grid on
 xlabel("\theta")
 ylabel("Normalized Pattern [dB]")
 title("sum and difference beam pattern in dB")
 legend('sum beam','difference beam')

%% error voltage
 % err_vol = real((w_diff.'*p_th2)./(w_sum.'*p_th2));
 % err_vol = sum(err_vol,1);
 

in this code , left beam and right beam is correct?

this case i think sum beam and diffence beam figure is needed to exchange but i can't find error in this code

Answer 1

[praguna manvi]

Hi @종영,

As I understand, you are looking to plot the sum and difference monopulse for a ULA. Refer to the documentation link below under the algorithms section for detailed information on the "sum-and-difference monopulse algorithm":

https://www.mathworks.com/help/phased/ref/phased.sumdifferencemonopulsetracker.step.html

If you are interested in performing tracking using the phased.SumDifferenceMonopulseTracker with the "sum-and-difference" method, refer to this example for more information:

openExample('phased/MonopulseTrackingOf500MHzEmitterExample')