Helical Antenna (Helix Antenna)

Helical Antenna (Helix Antenna)BHAVIN V KAKANIIT-NU

Introduction The helical antenna is a hybrid of two simple radiating elements, the dipole and loop antenna. It is basic VHF and UHF antenna which provides circular polarization. Consist of a thick cooper wire wound in the form of a screw thread forming a helix.

The radiating element is a helix of wire, driven at one end and radiating along the axis of the helix. A ground plane at the driven end makes the radiation unidirectional from the far (open) end. There are different types of ground plane: Flat ground plane Cylindrical cavity Frustrum cavityHelical beam antenna was proposed and invented by J.D.Krauss in 1946. Mostly used for satellite communication. Can be used as a feed for parabolic dish/ reflector antennas for getting much higher gain. A single helical antenna or an array of helices are useful in transmitting or receiving VHF signals through the ionosphere It is also used for space probe communications.Modes of Operation There are 2 modes of operation : Normal and Axial

Normal ModeAxial ModeNL