Connecting Spirals for Wideband Dual Polarization Phased Array

A technique is presented to design dual polarization spiral antenna phased arrays using mono polarization spirals in an alternating configuration. The proposed technique consists of connecting cross polarized neighboring spirals. Thus, the currents in the arms of one spiral flow into the arms of the adjacent spirals. In addition, the currents transmitted to the neighboring spirals radiate the same polarization, as a center fed spiral and an externally fed cross spiral radiate the same polarization. The optimization of the shape of the connection is also presented. The lowest operating frequency of the new array design is 1.8 times lower than an array of isolated spirals while being dual polarized and steerable +/- 30 degrees.