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[bacurrie45]

Hi i have successfully managed to design a two arm log spiral antenna with the following parameters however when i simulate in MATLAB my antenna arms do not truncate in a sharp arc the way i would like. I have attached my code and a diagram of my antenna. Any help would be apprecaited

a = 0.22
n = 2 turns
theta range = 0 to 4*pi
flow = 300Mhz
fhigh = 1Ghz
starting radius ro = 75mm



[code]>> clear all
alpha = 0.22;
delta = pi/2;
theta = 0:pi/60:4*pi*(2);
k = 0.075;
r1 = k*exp(alpha*theta);
r2 = k*exp(alpha*(theta-delta));
r3 = -k *exp (alpha*theta);
r4 = -k*exp(alpha*(theta-delta));
x = r1.*cos(theta);
y = r1.*sin(theta);

x1 = r1.*cos(theta);
y1 = r1.*sin(theta);
x2 = r2.*cos(theta);
y2 = r2.*sin(theta);
x3 = r3.*cos (theta);
y3 = r3.*sin (theta);
x4 = r4.*cos (theta);
y4 = r4.*sin (theta);

plot (x,y, 'b','linewidth',3); hold on; grid on;
plot (x1,y1,x2,y2,x3,y3,x4,y4,'r','linewidth',3); hold on; grid on ;
z = [x,y];
z = [x1,y1,x2,y2,x3,y3,x4,y4];
axis('equal')
rotate3d on