Layered microstrip helical antenna design

IV ABSTRACT LAYERED MICROSTRIP HELICAL ANTENNA DESIGN A novel broadband microstrip antenna has been developed to advance basic characteristics of microstrip antennas such as narrow bandwidth and low directivity. Patches which have the geometrical configuration of annular sector type are arranged on layered media. The diameters of the patches become smaller into the upper layers of the designed microstrip antenna. The active patches are connected to each other by a short transition wire; therefore the geometrical configuration of the novel antenna seems to be a tapered helical antenna. Analytical models and numerical techniques are applied to find the fundamental antenna parameters for an annular sector microstrip patch antenna, and the results are compared to each other. The analytical techniques, with some appropriate assumptions, based on superposition and array theorems in electromagnetics are applied for layered microstrip helical antenna design, and the results of the fundamental antenna parameters are compared with the results of those of uniform and quasi-tapered helical antennas, approximately. The study shows that the layered microstrip helical antenna increases the pattern bandwidth and the directivity of the antenna, and also reduces half- power beamwidth, as it is expected. The layered microstrip helical antenna can be analyzed by using Dyadic Green's functions to find out more accurate results. This method is complex to apply, therefore the mentioned approximate analytical models have been developed and applied.