what are the antennas which are circularly polarized?

Answer 1

Polarity of radio signals is determined by the electric field.
Most television stations use horizontal polarized antennas, FM is mostly a mix of horizontal and circular. Some very low power FM use vertically polarized antennas due to simplicity in installation.
DBS satellite uses a circular polarization rather than linear polarization.
A yagi antenna is usually either horizontally or vertically polarized. If you place two on a common boom, or separated by the correct distance, you can create a circular polarized signal. In this case the electrical field rotates, sort of like a cork screw.
Look for an FM broadcast tower with multiple antennas on the side. There are often 10 or 12 pods off to the side. These are commonly circularly polarized.
Check this web site. Dielectric makes broadcast antennas, including circular polarized types.
http://www.dielectric.com/broadcast/vhf.asp

Answer 2

just a guess, but I'm thinking its AM antennas, and VHF, uhf