On the synthesis of uniformly spaced dual polarized linear series-fed microstrip arrays: a partly empirical approach

The paper presents an approach to the design of uniformly spaced dual polarized microstrip series-fed linear arrays having a four-port slot-coupled cross patch as a basic element. The array is of the travelling wave type, with all elements resonating at the same frequency, and is designed for radiation in the broadside direction. For precise control of the current amplitude distribution and, thus, of the pattern shape, differing antenna sections are required to form the array. Particularly, for series-fed aperture coupled patch arrays, design flexibility can be greatly enhanced by simply varying the size of the coupling slots so as to excite properly the corresponding patches on the line. Upon the consideration that the slot size clearly affects both the transmission characteristics and the amplitude of the current excited on the patch, a novel, partly empirical, approach to the synthesis of the desired current amplitude tapering has been developed. The effectiveness of the proposed design approach is demonstrated through the synthesis of some prescribed excitation along the array.