A Pattern-Reconfigurable Endfire Antenna Based on Compact Folded Slot With Vertical Polarization

A pattern reconfigurable antenna with vertical polarization is proposed based on two folded near-coupled slot antennas. To achieve two endfire beams and a bidirectional beam, respectively, a central feeding structure and a reconfigurable feeding strip are designed based on the current reverse principle with the help of p-i-n diodes. A prototype has been fabricated and measured to validate this design. Three high-quality radiation beams have been obtained. In the two endfire states, the measured peak gain can reach 7.15 dBi and the front-to-back ( F/B ) ratio is more than 22 dB at 5.7 GHz. In the bidirectional state, the measured peak gain can reach 3.94 dBi and the F/B ratio is less than 0.3 dB.