This work focuses on the design of wideband dual polarized arrays using spiral antennas. These antennas are known for having wideband properties. But, due to the presence of the grating lobes, the bandwidth is decreased when using an array instead of a single antenna. In order to obtain a dual polarized array, it is needed to use elements of opposite polarization, which creates great distances between same polarization elements, meaning an earlier presence of the grating lobes. In this work, an analytic method was developed to estimate the bandwidth of the spiral arrays. This method showed that the maximum bandwidth of uniform spiral arrays is about an octave, for the mono-polarized case, and nonexistent for the dual polarized case. Working on the validation of the method, some resonances were observed. Explanations are presented, as well as possible solutions. Trying to expand the bandwidth of the array, it was found that it is possible and suitable to use at the same time the two current design paradigms for wideband arrays. Using this idea, a 6:1 bandwidth concentric rings array using connected spirals was achieved. Perspectives are also presented.
