A Time Modulated Array With Polarization Diversity Capability

The Time Modulated Array (TMA) provides multiple radiation beams at different frequencies, by turning the radiating elements on and off. In this paper, we propose to add polarization diversity to a wireless communication link by leveraging the capabilities of the TMA. The proposed architecture switches between two orthogonal polarizations, instead of turning the antenna off, providing polarization diversity for the receivers. We show that the beams of each polarization at the sidebands are exactly the same. However, the switching sequence should be optimized for the fundamental frequency to provide the same radiation level at each sideband. Two different switching sequences are proposed, which are optimized for different conditions. To evaluate the switching sequences and the diversity order of the system, an 8-element array with dual polarization antennas is fabricated. The radiating antenna element is a dual feed ring slot antenna, designed for 5.8 GHz with 10% fractional bandwidth. Both the single antenna and the array are measured in an anechoic chamber. The measurements indicate that the prototype provides full diversity gain along with multiple beam generation and beam steering, while it is very low cost and has low complexity.