Novel analytical procedures for folded strip dipole antennas

A new analysis method is described in this paper to accurately calculate the input impedance of a folded strip dipole antenna. Previous analytical procedures use a quasi-static approach to analytically predict the input impedance of an equivalent cylindrical folded dipole. The new design procedure takes advantage of new analytical equations for strip dipoles, and consequently does not need the equivalence between a rectangular and a circular cross section dipole antenna, which improves the accuracy of the analytical equations. In addition, a correction factor to the coplanar strip (CPS) transmission line length is presented to allow a wider separation between the strips of the folded dipole. Two examples are given to validate the accuracy of the newly proposed analytical procedure. The results of the analytical equations are compared with the results obtained by the electromagnetic simulation software CST Microwave Studio MWS®. The deviations between Analytical Equations (AE) and the Finite Integration Technique (FIT) do not exceed -11 dB (reflection), which makes this method 3.5 dB more accurate than the most recent reported analytical techniques (-7.5 dB). In addition, the newly proposed solution can be extended to analytically characterize different kind of antennas such as the log periodic, Yagi-Uda and folded dipole array antenna.