Reconfigurable Two-Dimensional Multibeam Antenna With Extended Coverage

In this letter, a two-dimensional (2-D) multibeam antenna with extended beam coverage is presented. By combining a modified 4 × 4 Butler matrix (BM) and phase reconfigurable antenna elements, a new multibeam antenna framework is constructed. The output ports of the 4 × 4 BM arrange along the 2-D direction to generate four different phase distributions, while the phase reconfigurable elements can provide additional phase shifting on these original multibeam phase distributions. As a result, each initial sub-beam can be extended into five sub-beams, thus increasing the beam coverage. To verify the design, a prototype of the proposed multibeam antenna is fabricated and measured. The measured −10 dB impedance matching bandwidth is 4.61 GHz to 5.32 GHz. The peak gain is 10.3 dBi. And the results also demonstrate that the antenna can switch its main beam within a 2-D space with a maximum elevation angle of 53°.