Patent attributes
A quadri-filar helical antenna structure includes a cylindrical body having a relative dielectric constant greater than 4, and four radial metal plates on a distal end of the cylindrical body, and each radial metal plate is extended along the cylindrical body. The ends of every two adjacent radial metal plates are connected to form two antenna structures, and a circuit board is fixed. A ground surface is installed on one side of the circuit board and coupled to one of the antennas. An impedance matching circuit is installed on another side of the circuit board, and one end of the impedance matching circuit is coupled to another antenna. A feeder is installed at another end of the impedance matching circuit. Four radial metal plates having an electric length about odd multiples of a quarter of wavelength of the cylindrical body can receive satellite signals.