Pattern Reconfigurable Antenna Array with Circular Polarization

A design for arrays with beam-steering capability in the azimuthal plane is described. The array is a four-sector antenna configuration, and each sector element can generate unidirectional radiation with circular polarization (CP). A reconfigurable 1 × 4 power divider with broadband operation is designed and used to excite the sector elements. By controlling PIN diodes, the divider can offer 11 states for the four outputs, and each state is corresponding to one CP radiation pattern of the array. Prototypes for the sector array and the tunable divider are, respectively, constructed, and the experimental results of the integrated structure demonstrate that, in addition to the beam-steering capability, the array can also generate bidirectional and omnidirectional radiation patterns between 1.9 and 2.3 GHz. Moreover, these steerable beams and radiation patterns have a cross polarization of less than -18 dB for all azimuthal angles.