Efficient analysis of finite microstrip phased array antennas

If one wants to design an array of microstrip antennas, it is of great importance that the mutual coupling between array elements is included in the analysis. Mutual coupling deteriorates the input impedance of each array element and affects the radiation pattern of the total array. Mutual coupling in microstrip phased array antennas can be analysed with two approaches: 1) finite array approach (element-by-element approach) and 2) infinite array approach. Small arrays and edge elements can only be analysed in a proper way if a rigorous finite array approach is used. In Arts and Smolders (1993) and Smolders (1993) a method was described to analyse finite arrays of stacked microstrip antennas, which may have an electrically thick one- or two-layer dielectric substrate. The method is based on the well-known spectral domain method of moments which includes the exact spectral domain Green´s function and which includes a very accurate model to describe the feeding coaxial cables. The present paper gives an improvement to this method.