Anotace:
The first aim of this work is to design a new geometry of printed helix antennas in a simple structure that only uses planar FR4 substrates, unlike conventional wire helix antennas. The main body of helix comprises four rectangular substrates containing helix arms forming a box. The printed helix arms are designed in a way that they meet each other in the edges of substrates when placed next to one another. The most important advantages of this work are introducing a method that makes the helix antenna fabrication and also the impedance matching procedure simpler. The presented helix antenna has end-fire radiation in Z-direction with circular polarization suitable for L- and S-bands applications. Simulated and measured results show that the proposed antenna has a wide impedance bandwidth of 1.37 GHz from 1.56 GHz to 2.93 GHz (more than 61%), the 3 dB axial ratio bandwidth of 1.18 GHz from 1.58 GHz to 2.76 GHz (more than 54%) and a maximum gain of 11.3 dBiC at 1.6 GHz.