Polarization Reconfigurable Aperture-Fed Patch Antenna and Array

This paper presents a reconfigurable aperture-fed patch antenna array for ±45° polarizations. First, a new method to realize the reconfigurable ±45° polarizations is proposed. It introduces controllable RF switches on a cross-aperture to excite a square patch for two orthogonal polarizations. The RF switches are controlled by two sets of DC biases, which could select the polarization through the reconfigurable aperture. Second, two patch antennas based on cross-aperture excitation are discussed. The first structure uses a split ground plane with four switches, while the other one employs a united ground plane with eight switches. Both antennas operate well as the single element. However, only the antenna with a united ground is suitable for developing a reconfigurable dual-polarized antenna array, owning to its simple DC biasing lines and the reconfigurable-controlling network. Both simulation and experiment studies were examined to verify the proposed design. The measured 10-dB impedance bandwidth of the array is 9.3%, which can cover the 2.4-GHz WLAN band. The desired radiation patterns were observed with a maximum gain of 13.5 dBi. The proposed antenna array has low cross-polarization and stable gain across the entire operating bandwidth.