Circular polarization microstrip array on a conical surface

Antenna elements based on microstrip technology are low profile, conformal, low weight and low cost, as such they are commonly used in many applications. Lately, extensive effort was devoted to compute the radiation characteristics of microstrip elements on flat and cylindrical surfaces, but only minor attention has been given to the analysis of microstrip elements on a conical surface. Such a geometry has a significant importance in satellite and space communication. We utilize the cavity model to compute the input impedance of the patch. We use spherical wave functions expansion to compute the internal cavity fields and the external radiated fields. The circular polarization of the microstrip element was obtained by exciting two orthogonal modes with 90/spl deg/ phase difference among them. To obtain an omnidirectional azimuth coverage, three microstrip elements were interconnected and equally spaced along the cone surface. The antenna was built and tested and good agreement between the computed and measured results was obtained.