Patent ID: 7268745

Claim:
A coaxial cable free quadri-filar helical antenna structure, comprising: a cylindrical body, made of an dielectric material with a relative dielectric constant larger than 4; four radial metal plates, each having an end disposed at a distal surface of said cylindrical body and extended from the center of said cylindrical body along a radial direction to an edge of said cylindrical body, and then extended in a helical course along an axial direction on the circumferential surface of said cylindrical body to another edge of said cylindrical body, and the corresponding ends of every two adjacent radial metal plates on a distal surface of said cylindrical body being coupled to form two antenna structures; and a circuit board, fixed at a position proximate to a distal end of said cylindrical body and having a ground surface disposed at a side, and said ground surface being electrically coupled to a set of said antenna structures, and an impedance matching circuit disposed on another side, such that an end of said impedance matching circuit is electrically coupled to another set of said antenna structures, and another end of said impedance matching circuit is a signal feeder end of said antenna structures.