A Broadband Reflectarray Using Phoenix Unit Cell

Comparative study of “Phoenix” reflectarray phase-shifting cells

“…This bandwidth is drastically reduced for an oblique angle of incidence due to parasitic resonances (as explained in section 2). The cell proposed in [12] (inspired from [11]) also shows an acceptable bandwidth (~15%) for a normal incidence. However, the effect of the oblique incidence on the bandwidth was not shown.…”

“…Few years later, two alternative topologies derived from the original "Phoenix" cell were proposed. The first one [12], designed to operate at 10GHz, was tested on a 225-element reflectarray fed with a linearly polarized Vivaldi antenna. Measurements show a 1-dB gain bandwidth of 29%.…”

Principles of Ideal Wideband Reflectarray Antennas

“…This is because the frequency slope of RAA cells, dφmn df , is inherently negative [2][3][4][5][6][7][8][9][10][11][12][13][14]. Figure 2 illustrates the required phase-frequency response of the mn-th cell of a wideband RRA with center frequency of f 0 and bandwidth from f l to f u .…”

“…Even so, the broadening of bandwidth of RAAs is not so successful. In most of works such as in [8][9][10][11][12][13][14], 1-dB gain bandwidth is reported around 30% at most. This is because of ignoring this important fact that only having cells of linear phase response is not enough.…”

“…In other words, the phase slopes of all cells of a wideband RAA must not be identical but they should be different from each other. In references such as [8][9][10][11][12][13][14], the phase slopes of all cells are considered equal which limits broadening the bandwidth.…”