A Dual-Polarized Wideband Planar Phased Array With Spiral Antennas

The design of a wide bandwidth dual-polarized phased array of Archimedean spiral antennas with cavity is presented. The reflection coefficient, circular polarization and grating lobes are addressed independently in the design process. Uniform concentric rings array is used to control the grating lobes, thanks to its non uniform spatial distribution, and obtain a good circular polarization, thanks to its rotational symmetry. Simulations of one-ring array agree with the measurements. Adding more rings keeps the side lobes level to less than -10 dB, relative to the main lobe. The dual-polarized array can scan up to θ = 30° keeping a low reflection coefficient and low side lobe levels.