Circular polarization in rectangular waveguide

[cefl]

Homework Statement

In a rectangular waveguide, b = a/2, find the section, if exists, in which the magnetic field is circularly polarized (TE₁₀ mode).

Homework Equations

Rectangular waveguide equations for TE₁₀ mode (referencing Pozar book).
Circular polarization (π/2 out of phase and same amplitude).

The Attempt at a Solution

For TE₁₀ mode: H_z, E_y and H_x are known, E_x = E_z = H_y = 0.
For the magnetic field to be circularly polarized H_z and H_x must be π/2 out of phase so π/2 = tan^-1(H_z/H_x), but I'm not sure about this since H_x is already multiplied by 'j'.

Someone might help, please?

 

[cefl]

Nobody?