Mode (electromagnetism)
The mode of electromagnetic systems describes the field pattern of the propagating waves.
Some of the classifications of electromagnetic modes include;
- Modes in waveguides and transmission lines. These modes are analogous to the normal modes of vibration in mechanical systems.
- * Transverse modes, modes that have at least one of the electric field and magnetic field entirely in a transverse direction.
- ** Transverse electromagnetic mode, as with a free space plane wave, both the electric field and magnetic field are entirely transverse.
- ** Transverse electric modes, only the electric field is entirely transverse. Also notated as H modes to indicate there is a longitudinal magnetic component.
- ** Transverse magnetic modes, only the magnetic field is entirely transverse. Also notated as E modes to indicate there is a longitudinal electric component.
- * Hybrid electromagnetic modes, both the electric and magnetic fields have a component in the longitudinal direction. They can be analysed as a linear superposition of the corresponding TE and TM modes.
- ** HE modes, hybrid modes in which the TE component dominates.
- ** EH modes, hybrid modes in which the TM component dominates.
- ** Longitudinal-section modes
- *** Longitudinal-section electric modes, hybrid modes in which the electric field in one of the transverse directions is zero
- *** Longitudinal-section magnetic modes, hybrid modes in which the magnetic field in one of the transverse directions is zero
- *The term eigenmode is used both as a synonym for mode and as the eigenfunctions in a eigenmode expansion analysis of waveguides.
- **Similarly natural modes arise in the singular expansion method of waveguide analysis and characteristic modes arise in characteristic mode analysis.
- Modes in other structures
- * Bloch modes, modes of Bloch waves; these occur in periodically repeating structures.