EMF was always Electro Motive Force in the books I learned from
there is no such thing as an electromagnetic field
electric field
magnetic field
saying
>EM field verses RF field.
is gibberish
2.1 General Field and Wave Equations.
If the fields are circularly symmetric about the axis and assumed to vary with [math]e^{j\omega t \,- \, \gamma\, z}[/math]
The TE wave is described by:
(1)
[math] \gamma E_\phi + j\omega\mu \, H_r = 0 [/math]
[math]\frac {1}{r} \frac {\partial}{\partial_r}\, (rE_\phi) + j\omega\mu \, H_r = 0[/math]
[math]\frac {\partial H_z}{\partial_r} + \gamma H_r + j\omega\epsilon \, E_\phi = -J_\phi [/math]
The TM wave is described by:
(2)
[math]\gamma H_\phi - j\omega\epsilon \, E_r = J_r [/math]
[math]\frac {1}{r} \, \frac {\partial}{\partial_r} \, (rH_\phi) - j\omega\epsilon \, E_z = J_z[/math]
[math]\frac {\partial E_z}{\partial_r} + \gamma E_r - j\omega\epsilon \, H_\phi = 0 [/math]
Where:
z is helix axis
r is helix radius
[math]\phi[/math] is angle of helix (thread pitch angle)
[math] \gamma = \alpha + j\beta [/math] is the propagation constant along the z axis
[math]E_z , E_r , E_\phi [/math] are the electric field components
[math]H_z , H_r , H_\phi [/math] are the magnetic field components
[math]J_z , J_r , J_\phi [/math] are the components of the vector current density
The grouping of field components into TE and TM waves is for mathematical convenience only. All six components are required to satisfy the boundary conditions on the helix. From the field equations the following inhomogeneous wave equations for [math] H_z \: and \; E_z\:[/math] can be deduced.
(3)
[math]\frac{1}{r}\,\frac {\partial}{\partial_r} \,(r\frac {\partial H_z}{\partial_r})+(\gamma^2 + k^2)\,H_z \; = \; -\frac {1}{r}\,\frac {\partial}{\partial_r}\,(r\:j_\phi)[/math]
(4)
[math]\frac {1}{r}\,\frac{\partial}{\partial_r}\,(r\frac{\partial E_z}{\partial_r})+(\gamma^2 + k^2)\,E_z \; = \; -\frac {(\gamma^2 + k^2)}{j\omega\epsilon} \, J_z \: + \: \frac {\gamma}{j\omega\epsilon}\,\frac{1}{r}\,\frac{\partial}{\partial_r}\,(rJ_r)[/math]
where [math]k^2\,=\,\omega^2 \mu\epsilon [/math]