Design of dual-polarized series-fed microstrip arrays with low losses and high polarization purity

The design of a dual-polarized microstrip series-fed linear traveling-wave array is described in this paper. The array is composed of two identical subarrays formed by cascading an equal number of four-port aperture-coupled cross-patch elements and terminated on a two-port radiating matched load. By properly exciting the array, dual linear or circular polarization can be accomplished and by virtue of the symmetric arrangement of the antenna cross- polarization is annihilated. A straightforward design strategy is proposed for the synthesis of a desired current distribution along the array antenna. Some proof-of-concept linear arrays are developed and the corresponding numerical results, obtained through a full-wave approach based on the method of moments (MoM), are provided. As an independent validation, supplementary analyses by the finite integration technique (FIT) are also reported. Very close agreement is found between prescribed and synthesized array performance, which qualifies the proposed design approach as an accurate and effective tool for the synthesis of series-fed aperture-coupled patch arrays.