Antenna Analyzer AIM4170 page 41
The magnitude of a complex number is the square root of the sum of the squares of the
real part and the imaginary part:
Magnitude_of_Z = SQRT( 500*500 + 227*227) = 549 ohms
The phase angle, Theta, associated with this complex number can be calculated by:
Theta = ArcTangent(Imaginary_part / Real_part)
= ArcTangent(-227/500) = - 24.4 degrees
The negative angle is characteristic of a capacitive circuit. It means the voltage is trailing
(or lagging) the current. In an inductive circuit, the phase angle is positive since the
voltage leads the current.