%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Figure 4.41% Response of cylindrical array versus phi for theta = 0.5137*pi% Xin Zhang 9/21/99% Updated by K. Bell 9/30/00
% Updated by Lillian Xu 12/06/2000, K. Bell 7/23/01, 9/30/01%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Description:%    Redrawing of Figure 4.41,% Parameters:%    N=25clear allclose allRl=5/pi;N=25;Ms=21;M=(Ms-1)/2;theta=0.5137*pi;Mm=(-M:1:M)';phi=(-1)*pi:0.002*pi:pi;SL = -20;nbar = 6;d = Rl*2/N;R = 10^(-SL/20);x0 = cosh(acosh(R)/(Ms-1));cc=cos((2*[1:1:floor((Ms-1)/2)]-1)*0.5*pi/(Ms-1)).';udc = acos(cc/x0)/(pi*d);if rem(Ms,2)==0   uu = [1:1:(Ms/2)-1].'/(Ms*d)   u_nbar = udc(nbar);       % u_nbar Chebychev   sigma = nbar/(Ms*d*u_nbar);   udcmod = udc*sigma;           % modified Chebychev   uz = [udcmod(1:nbar-1);uu(nbar:(Ms/2)-1)];   ut = [uz;-uz;-1]else   uu = [1:1:(Ms-1)/2].'/(Ms*d);   u_nbar = udc(nbar) ;      % u_nbar Chebychev   sigma = nbar/(Ms*d*u_nbar);   udcmod = udc*sigma;           % modified Chebychev   uz = [udcmod(1:nbar-1);uu(nbar:(Ms-1)/2)];   ut = [uz;-uz];endut;w = poly(exp(j*2*pi*d*ut)).';Wh=w/sum(w);for n=1:Ms   m=n-1-M;   if m<0      Wpm(n,1)=Wh(n,1)/besselj(abs(m),2*pi*Rl)/(-1)^m;   else      Wpm(n,1)=Wh(n,1)/besselj(m,2*pi*Rl);   endendWpm = Wpm./sum(Wpm);for n=1:Ms   m=n-1-M;   if m<0      Vj(n,1)=besselj(abs(m),2*pi*Rl*sin(theta))*(-1)^m;   else      Vj(n,1)=besselj(m,2*pi*Rl*sin(theta));   endendJ=diag(Vj);V=exp(j*Mm*phi);B1=Wpm'*J*V;B1 = abs(B1)/max(abs(B1));Ll = 10;Bd = sinc(Ll*cos(theta));B = B1.*Bd;Bm=20*log10(abs(B));figureplot(phi/pi,Bm)gridaxis([-1 1 -60 0])xlabel('\phi/\pi','Fontsize',14)ylabel('Beam pattern (dB)','Fontsize',14)%title('Response of Cylindrical Array, \theta = 0.5137\pi')