Design and Implementation of a Planar Polarization-Reconfigurable Antenna

In this letter, a planar low-profile 2 x 2 polarization-reconfigurable antenna array using complementary square split-ring antenna element based on substrate integrated waveguide technique is proposed for wireless applications. p-i-n diodes are adopted in the design for switching the radiation polarization. Three types of polarizations including linear polarization (LP), left-hand circular polarization, and right-hand circular polarization can be achieved by properly controlling the states of the two p-i-n diodes. A 2x2 rotated-element array is developed to demonstrate the feasibility of array application. Prototype of the 2 x 2 antenna array is manufactured and tested. The measured and simulated results verify the performance of the proposed antenna. The measured results show that the antenna array has an impedance bandwidth (S-11 < -10 dB) of 7.98-8.75 GHz and a 3-dB axial-ratio bandwidth of 8.18-8.45 GHz for the two CP modes, and has an impedance bandwidth of 8.01-8.24 GHz for the LP mode. The measured maximum gains of the two CP modes and the LP mode are 10.47, 9.9, and 10.75 dBi, respectively. This polarization-reconfigurable antenna has a good performance and a single-layer structure, which can be used for wireless communication systems.