Fast frequency sweep of metallic antennas using frequency-independent reaction and enhanced gap source model

In this paper, the enhanced gap source model is combined with the frequency-independent reaction(FIR)-MoM to analyze the input impedance of the metallic antenna over a wide frequency band. The enhanced gap source model is a simple feeding model, which can overcome the instability of the gap source model. Thus, the stable results can be obtained. In the FIR-MoM, the exponential of the Green’s function is expanded as Taylor series in terms of the distance between the centers of the testing and source functions. The impedance matrix is expressed as the summation, in which each term is the multiplication of the frequency-independent matrix and the frequency-dependent phase term. The frequency-independent matrices are computed before the frequency sweep. Thus, the efficiency of the FIR is very high. The impedance matrix can be efficiently generated when the FIR is used for frequency sweep. The FIR-MoM is suitable for the whole frequency range. Moreover, the precision can be dynamically improved. By combining these two techniques, the stable results over a wide frequency range can be efficiently obtained. To test the accuracy and efficiency of the proposed method, two numerical examples are implemented. Numerical results validate the accuracy and the efficiency.