A polarization-agile aperture-coupled patch antenna using quad-mode reconfigurable feeding network

This paper presents a new polarization-agile antenna that can switch between four various polarizations. The proposed antenna is based on a quad-mode reconfigurable feeding network with four dynamic transmission modes. At each mode, the measured insertion loss of the feeding network is less than 0.8 dB at the target frequency. Meanwhile, a dual-polarized aperture-coupled patch antenna with good isolation and the same gain between two ports is designed for the realization of the polarization diversity. The feeding network can be integrated into the dual-polarized antenna to form the polarization-agile antenna. By switching the PIN diodes on the feeding network, the proposed antenna can exhibit two orthogonal linear polarizations and two orthogonal circular polarizations. Measured results of the polarization-agile antenna are shown in detail, which verify its performance.