The halo antenna used two or more parallel loops but now most use single conductor and it uses a resonant antenna and is similar to the simplest antenna, rabbit ears for example, called dipole antenna
Early halo antennas used two or more parallel loops, modeled after a 1943 patent which was a folded dipole bent into a circle. More recent halo antennas have tended to use a single conductor fed with a gamma match. A halo antenna, or halo, is a 2 wavelength dipole antenna, which has been bent into a circle with an electrical break directly opposite the feed point. A common example of a dipole is the "rabbit ears" television antenna found on broadcast television sets. 
