Characterization of multiband antennas using the singularity expansion method

Abstract

ABSTRACTThis article presents modeling of multiband antennas using the Singularity Expansion Method (SEM). The SEM with an improved pole‐residue extraction scheme is developed to precisely characterize multiband antennas in the time and frequency domains. To acquire the accurate physical complex poles and the corresponding residues of the antenna model, a two‐step modified Matrix Pencil (MP) method has been applied to the impulse response of the antenna. A specific time segment parameter TS is introduced to improve the performance of the MP method to extract the actual physical poles and eliminate the nonphysical poles caused by the early time response of the multiband antennas. Furthermore, an adjustable filtering parameter P is used to reject the low energy nonphysical poles between the sensitive multiple bands of the antenna. The proposed MP scheme is applied to the far‐field impulse response of three multiband (dual, triple, and quad band) antennas. The poles extracted by the proposed modified MP method are located precisely within the multiple operating bands of each of the tested antennas. The one set of the developed parameters is used to accurately characterize multiband antennas in both the time and frequency domains. A triple band fractal like antenna has been fabricated and its far‐field impulse response is measured and then reconstructed using the SEM based model. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1012–1018, 2017