A Compact Tri-Band Penta-Polarization Reconfigurable Planar Antenna for Interference Management in 5G Ultra-Dense Network Environment

Interference and multipath are the most common issues in the wireless domain due to the coexistence of a large number of wireless nodes operating within the constraint spectrum. A compact planar antenna with five reconfigurable polarization states in three distinct operating bands is presented in this article. A square patch is enclosed by a square outer ring in the design, and these antennas are coupled-decoupled successively using switching diodes to excite three distinct operating bands. Coplanar microstrip lines are used to feed the orthogonal edges of the antenna. The diagonal corners of the inner and outer ring patches are truncated to realize dual circular polarization (CP) states with proper biasing. Switching diodes are placed at the etched corners to realize vertical (VP) and horizontal (HP) polarization. Both the orthogonal feed lines are activated simultaneously with identical phase and amplitude to realize 45° linear polarization. A low-profile, single-feed, compact prototype reconfigurable microstrip antenna (MSA) is finally designed, fabricated, and measured at 1.8 GHz, 2.4 GHz, and 5.8 GHz bands, respectively. Each operating band shows five distinct operating states. The simulation results for all fifteen states are found to be consistent with the measurement.