Deembedding of lossy Foster networks

Data-processing procedures are described, which should be useful for measurement of the radiation Q factors of small antennas such as microstrip patch antennas or dielectric-resonator antennas. Typical values of radiation Q factors are quite low, of the order of ten or even smaller. Two equivalent Foster-type networks are proposed, modified for the presence of losses: one for the single resonance behavior, and another for the dual resonance behavior. The individual network elements are determined by optimization. A least squares procedure is described that can provide a good estimate for the starting values of the optimization.