Bandwidth enhancement of a pattern reconfigurable antenna array using series-feeding slots

A pattern reconfigurable antenna array with series-feeding slots for broadening the bandwidth is proposed in this paper. There are four operating modes for the proposed antenna array by controlling the on-off states of the PIN diodes, which are embedded in the branches on the top board of the antenna. The measured results show that the return loss is better than -10 dB over 2.04 - 2.38 GHz at all four operating modes for the proposed antenna, and the mutual coupling between the antenna elements is below -12.25 dB in the whole operating band. Reconfigurable patterns can be obtained by means of mode conversion.