A simple decoupling method applied in gain improvement of a planar array antenna

A 4 × 4 patch array antenna based on loading shorting vias is proposed in this letter. The excitation method of the array antenna adopts stripline coupling feed, leading to a strong mutual coupling between the adjacent elements. The realized gain and impedance match are deteriorated seriously. Then, eight groups of metallic vias are introduced to the array antenna. By adjusting their number and spacing, the radiation performance of the array antenna can be improved significantly. Finally, the experiment results show that the proposed array antenna resonates at 5.4 GHz. Compared with the antenna without shorting vias, one resonance point caused by the mutual coupling can be removed within 5.34 GHz to 5.46 GHz. The gain drops unexpectedly, which is improved as well.