A feeding circuit for switching omni-directional and directive patterns

In this paper, we propose a novel feeding circuit for switching an omni-directional and directive radiation patterns. The proposed circuit changes the radiation patterns by phase differences and switching of the feed elements, and it has five operation modes. We illustrate the operation principle, the output characteristics and the obtained radiation patterns. The analytical results show that the mismatch losses are less than -1 dB, and the phase differences required to switch the radiation patterns are obtained around 2 GHz. Finally, we reveal that uni-, bi-and omni-directional radiation patterns are obtained in combination with a monopole array.