A bidirectional waveguide antenna with polarization reconfigurable capability

A bidirectional metallic waveguide antenna with polarization reconfigurable capability is presented in this study. The polarization states of the proposed design can be flexibly reconfigured among two orthogonal circular polarizations (CP) and linear polarization (LP) simply by selecting four different combinations of microstrip feeding branches with switches. Two identical rectangular metal sheets perpendicular to each other were inserted into the diagonal directions of a waveguide aperture. They were excited with the same amplitude, but with 0 degrees, 180 degrees, 90 degrees, or 270 degrees phase difference by choosing two of four microstrip feeding segments each time, and left-band CP, right-hand CP, and LP could be generated, respectively. Meanwhile, the sense of CP in two opposite radiating directions was also the same for either sense of CP. The proposed reconfigurable antenna can provide link reliability and polarization diversity for mobile wireless communications in a multipath propagation environment. In addition, it alone can realize multifunctional operations and thus reduce system complexity and cost. Details of antenna design are shown, and measured results for the constructed prototype are exhibited and discussed. (c) 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:422-427, 2014