Formula

Eθ = [ ( j*k*a2*E0*e-jkr ) / r ] * Sinφ [ ( J1*k*a*Sinθ) / k*a*Sinθ ]
Eφ = [ ( j*k*a2*E0*e-jkr ) / r ] *(Cosθ*Cosφ) [(J1*k*a*Sinθ) / k*a*Sinθ]

Where,
k = 2π / λ
λ = Wave Length
E0 = 8.8541878176 * 10-12F/m (electric constant)
θ = Coordinate Angle 1
φ = Coordinate Angle 2
a = Radius of Circular Aperture
r = Distance of the observation point from the Origin
j = Electric Current Density
J1 = Electric Current Density for 1st element