Proposal of Single-Feed Microstrip Antenna for Quad-Polarization Agility With Short-Ended Microstrip- Line Perturbation

Abstract

This manuscript proposes a single-feed quad-polarized antenna for 5.8-G Hz band applications. The antenna contains a switchable feed network, a single microstrip antenna and PIN diodes. The antenna also employs a short-ended microstrip-line perturbation for achieving circular polarization. The switchable feed network employs two PIN diodes to control its two branch to achieve two linear (LP) modes switching. A third diode is integrated between the perturbation segment and upper corner of the patch element. By activating the perturbation to function together with the radiating patch element, the same antenna can generate two circular polarization (CP) modes. The concept is examined through simulation. The impedance bandwidth for LP and CP conditions are about 1.6% and 2.6%, respectively. Around 0.7% 3-dB axial ratio bandwidth is observed within the range of interest.