Mode (electromagnetism)

The mode of electromagnetic systems describes the field pattern of the propagating waves.[1]: 369 

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.[2]: A.4 
    • Transverse modes, modes that have at least one of the electric field and magnetic field entirely in a transverse direction.[3]: 52 
      • Transverse electromagnetic mode (TEM), as with a free space plane wave, both the electric field and magnetic field are entirely transverse.
      • Transverse electric (TE) modes, only the electric field is entirely transverse. Also notated as H modes to indicate there is a longitudinal magnetic component.
      • Transverse magnetic (TM) modes, only the magnetic field is entirely transverse. Also notated as E modes to indicate there is a longitudinal electric component.
    • Hybrid electromagnetic (HEM) 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.[4]: 550 
      • HE modes, hybrid modes in which the TE component dominates.
      • EH modes, hybrid modes in which the TM component dominates.
      • Longitudinal-section modes[5]: 294 
        • Longitudinal-section electric (LSE) modes, hybrid modes in which the electric field in one of the transverse directions is zero
        • Longitudinal-section magnetic (LSM) 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[2]: 5.4.3  and as the eigenfunctions in a eigenmode expansion analysis of waveguides.[6]
      • Similarly natural modes arise in the singular expansion method of waveguide analysis and characteristic modes arise in characteristic mode analysis.[6]
  • Modes in other structures
    • Bloch modes, modes of Bloch waves; these occur in periodically repeating structures.[7]: 291 

Mode names are sometimes prefixed with quasi-, meaning that the mode is not quite pure. For instance, quasi-TEM mode has a small component of longitudinal field.[8]: 123 

  1. ^ Jackson, John David (1975). Classical electrodynamics (2d ed.). New York: Wiley. ISBN 978-0-471-43132-9.
  2. ^ a b Rothwell, Edward J.; Cloud, Michael J. (2001). Electromagnetics. Electrical engineering textbook series. Boca Raton, Fla: CRC Press. ISBN 978-0-8493-1397-4.
  3. ^ Cite error: The named reference Connor1972 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Chen2004 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference ZhangLi2008 was invoked but never defined (see the help page).
  6. ^ a b Huang, Shaode; Pan, Jin; Luo, Yuyue (2018). "Study on the Relationships between Eigenmodes, Natural Modes, and Characteristic Modes of Perfectly Electric Conducting Bodies". International Journal of Antennas and Propagation. 2018: 1–13. doi:10.1155/2018/8735635. hdl:10453/132538. ISSN 1687-5869.
  7. ^ Cite error: The named reference Yang2010 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference EdwardsSteer2016 was invoked but never defined (see the help page).