horn anteena

IT is based on Aperture Antenna analysis..in which Horn is considered as Recentangular aperture excited by some x or y or z polarised wave.This gives rise to Aperture field i.e E and H components at the Aperture itself.
Based on this Ea and Ha the far field pattern can be calculated which is based on Huygen's priciple where aperture field is considered as secondary source which gives rise to far field region of radiation.
You need to check chapter 12(don't remember exactly) from Balanis Antenna Theory book which is considered as Foundation of Aperture Antennas.
Tough the analysis is very much mathematical it is quiet interesting and fun if you understand.

Hi sumant.thapliyal,

Horn Antenna is an opened out waveguide.It consists of flared waveguide so that the wave inside the guide expands in an orderly manner.i.e a waveguide is capable of radiating into open space provided it is excited at one end and opened at other end.

Dear sumant.thapliyal,

For visualizing the theory, check the following URLs.
* http://imodelit.com/ViewDetails.aspx?AID=240
* http://imodelit.com/ViewDetails.aspx?AID=241

Best Regards,
imodelit Moderator

A waveguide section of a typical horn antenna is excited with TE10 mode from a coaxial probe feeder.