One-point-fed circularly polarized Yagi-Uda loop array

A one-point-fed circularly polarized Yagi-Uda loop array is introduced. As the driven element a one-point fed circular loop wire with one gap is used. It is expected that the loop radiates good circular polarization due to the duality of the annular slot antenna. The reflector and directors are circular loop wires. The advantage of the array is that one can change the sense of polarization easily by changing the position of the gap of a driven element. The characteristics, including the effect of the feed cable, are investigated numerically and experimentally. For a three-element array the gain is about 8 dBi, the minimum axial ratio is 0.4 dB and the front to back ratio is 15 dB.