Differentially-fed dual-polarization four beam pattern reconfigurable antenna

A planar differentially-fed dual-polarization four beam pattern reconfigurable antenna is proposed in this paper. It is composed of two orthogonal dual-dipole elements and four parasitic elements embedded with four PIN diodes. The two dual-dipole elements are overlapped and 90° rotational symmetrical, making the overall structure very compact. Dual-dipole elements are excited differentially through short microstrip feeding lines. All dipoles and parasitic elements are etched on the same substrate, resulting in a full planar structure. Four beam pattern reconfigurability and dual-polarization reconfigurability are realized by switching the combinations of PIN diodes states. The antenna obtains a −10 dB impedance bandwidth of 8.9% covering from 3.27 to 3.58 GHz, an average gain of 5.6 dBi, an FBR about 10 dB, and average radiation efficiency of 68% in the measurement. The proposed antenna has compact structure, low cost and easy processing.