Analysis and design of series-fed arrays of printed-dipoles proximity-coupled to a perpendicular microstripline

An analysis of a printed dipole element and a generalized configuration of a series-fed array of such elements, electromagnetically coupled to a covered microstripline running perpendicularly under it in a substrate-superstrate configuration, is presented. The solution is based on the principle of reciprocity and is formulated using a rigorous method of moments and full-wave spectral-domain Green´s functions for multilayer dielectric substrates. The dipole excitation is characterized by an equivalent impedance, and can be controlled by suitably selecting the offset of the dipole from the feed line. Mutual coupling between dipoles is included. Using the results of the element analysis, a series-fed array prototype has been successfully designed, built, and tested in a standing-wave configuration; the design details are described, and measured performances are evaluated using the results of the array analysis. Mutual coupling effects are found to be not detrimental for this configuration, but can be severe for other nonstanding-wave configurations