Mean and differential phase centers of rectangular dielectric rod antennas

Dielectric rod antennas of rectangular ernss section are of increasing interest at millimeterwave frequencies. Fur many applications like e.g. densely packaged feed arrays for refleetornens systems or electromagnetic field probes the exact knowledge of the phase center location is required. This paper will describe two efficient methods to determine the mean and differential phase center Incations of such antennas by means of numerical electromagnetic field simulations and a subsequent analysis of the computed antenna phase pattern. Phase center locations of various dielectric rod antennas with rectangnlar c m section are presented and the influence of geometrical parameters and frequency on the phase center location are analyzed and discussed in detail. The theoretically derived results are also compared tu measurements performed at X-hand frequencies.