Slot multi-arm helix antenna with simple and efficient feeding network

A slot helix antenna with a simple and efficient feeding network for satellite communications and global positioning system (GPS) applications is presented. Rectangular slotted openings, ended with fan-shaped slots, are designed for the helix-shaped slot radiating arms so as to obtain excitation from the circular microstrip feeding line. By adjusting the coupling, the four or more slot radiating elements can obtain appropriate excitation, which leads to the good circular polarisation properties of the antenna.