antenna-theory.com

[msg]

Can some one explain co-linear, broadside, end-side, and long-periodic antennas.

[bigSteve]

Some of what you are describing is antenna types, and some are antenna characteristics.

Co-Linear Antenna: This is a type of antenna. Basically this is somewhat like a dipole antenna, except it is meandered a bit approximately every half wavelength. This is so that the current will add in phase (i.e. if you have one long antenna the current will be sinusoidal; hence some parts will add constructively or destructively). The result is an antenna that has a higher directivity than a half-wavelength dipole antenna, but maintains peak radiation in the broadside direction

Broadside: This is a characteristic of an antenna. An Antenna is broadside if the radiation pattern is perpendicular to the antenna itself. So a dipole antenna has a broadside pattern (if the length is 0.5 wavelengths or less).

End-Side: This is another characteristic of an antenna related to it's radiation pattern. This is also called an end-fire antenna. In this case, the radiation of the antenna is along the direction of the antenna (i.e. 90 degrees out of phase to the broadside radiation pattern case)

Log-Periodic Antennas: This is a collection of antenna types. You wrote long-periodic, but I can assure you it is Log-Periodic. These antennas have a symmetry about them such that some length of the antenna grows logarithmically - i.e. the ratio of adjacent arm lengths on a Yagi-type antenna might be set to a constant. This is so multiples of the fundamental frequency see the same structure. These antennas are often very wide bandwdith.

Some links:
http://www.antenna-theory.com/antennas/dipole.php
http://www.antenna-theory.com/antennas/travelling/yagi.php