Efficient wide-band evaluation of mobile communications antennas using [Z]or [Y] matrix interpolation with the method of moments

The development of novel antennas for mobile communications often relies on performance simulations. The evaluation of the antenna surface currents fo r many frequencies using the method of moments (MoM) can take a long time s ince the impedance matrix must be computed for each new frequency, This pap er investigates and compares two efficient methods for the computation of t he broad-band performance of mobile communications antennas using frequency interpolation of either the MoM impedance matrix [Z] or admittance matrix [Y]. In either method, the elements of only a few matrices at relatively la rge frequency intervals are directly computed, These matrices are then used to interpolate the elements of the respective [Z] or [Y] matrices at the i ntermediate frequencies. Both methods reduce the time it takes to compute t he antenna performance over a wide frequency band. The implementation of ea ch method to evaluate the performance of several different antennas used fo r mobile communications is discussed, Examples with both frequency-domain a nd time-domain results are presented and both near-field and far-field quan tities are considered. The accuracy, the simulation run times, and the comp utational requirements of direct MoM, [Z] matrix interpolation, and [Y] mat rix interpolation are compared.