Dual Polarization Interleaved Spiral Antenna Phased Array With an Octave Bandwidth

A technique to design dual polarization spiral antenna phased arrays using mono polarization spirals is presented. The proposed technique consists of two interleaved subarrays, one for each polarization. The position of every spiral antenna is optimized through a genetic algorithm so that each array is nearly the size of the platform while having low sidelobes. Both resulting arrays have the same properties and are steerable. This method also helps to increase the bandwidth. An 80-element spiral array (spiral of width 0.25 m) with dual polarization is demonstrated, its beam can be steered +/- 30 degrees over almost one octave (1.97:1). The physical rejection of the sidelobes (i.e., without weighting) is about -10 dB.