All-Metal Phased Array with Full Polarization Reconfigurability

An all-metal phased array with full polarization reconfigurability is presented in this paper. Septum polarizers as phased array elements are first used to achieve left-handed and right-handed circular polarizations (LHCP and RHCP), and arbitrary linear polarizations (LPs) can be further synthesized. Two pairs of metal ridges are loaded into the septum polarizer to reduce the profile and aperture size, so that the spacing between the two adjacent array elements can be constrained to about half of the free-space wavelength at the center operating frequency. Phased arrays of 1 × 8 and 8 × 8 elements covering 25.5 - 27 GHz are designed to demonstrate the 1-D and 2-D beam scanning performance with different polarizations. For demonstration, the 1 × 8-element phased array is implemented. Experimental results show that the array exhibits stable beam scanning performance for both CPs and LPs. The synthesized beam scanning range is up to ±55° with a gain-reduction of 4.7 dB for all polarizations. Under beam scanning, the axial ratio (AR) remains below 3.1 dB for the LHCP and RHCP, and the maximum gain variation during polarization reconfiguration is less than 0.8 dB.