# Phase of s11 and Z

Antenna system resonance and the nanoVNA contained the following:

## Relationship between angle of reflection coefficient and angle of impedance

It was stated above that the angle (or phase) of s11 or Γ is not the same as the angle (or phase) of Z.

Given Zo and Γ, we can find θ, the angle of Z.

$$Z=Z_0\frac{1+\Gamma}{1-\Gamma}$$

Zo and Γ are complex values, so we will separate them into the modulus and angle.

$$\left | Z \right | \angle \theta =\left | Z_0 \right | \angle \psi \frac{1+\left| \Gamma \right | \angle \phi}{1-\left| \Gamma \right | \angle \phi} \\ \theta =arg \left ( \left | Z_0 \right | \angle \psi \frac{1+\left| \Gamma \right | \angle \phi}{1-\left| \Gamma \right | \angle \phi} \right )$$

We can see that the θ, the angle of Z, is not simply equal to φ, the angle of Γ, but is a function of four variables: $$\left | Z_0 \right |, \psi , \left| \Gamma \right |, \& \: \phi$$ .

It is true that if ψ=0 and φ=0 that θ=0, but that does not imply a wider simple equality. This particular combination is sometimes convenient, particularly when ψ=0 as if often the case with a VNA.