Increasing the Bandwidth of Reflectarray Antennas Using the Frequency Pulling Technique

In this work, a frequency pulling technique (FPT) is used to increase the bandwidth of traditional reflectarray antennas (RAs). Specifically, the bandwidth of a rectangular patch unit cell is doubled by simultaneously feeding it at two slightly asymmetric points. The required phase shift for each unit cell of our reflectarray is achieved using meandered microstrip lines below the patch elements. Our results illustrate that our proposed RA achieves a fractional gain bandwidth of 30%, which is approximately two times greater than the 16% fractional bandwidth of the traditional RA with single-point fed patches.