Techniques for model-based parameter estimation of antenna radiation patterns

A hybrid method for the simultaneous interpolation of antenna radiation patterns in the spatial and frequency domains is presented which combines the Pade rational function, a common MBPE fitting model, with a polynomial function to account for spatial variation. One of the most attractive features of this method is that a single set of previously determined interpolation coefficients can be used to reproduce an entire radiation pattern for a particular antenna at any frequency within its operational range, and with any desired angular resolution. Two methods for performing this hybrid interpolation will be presented and discussed in this paper. The first uses a generalized form of the Pade rational function and a multiple-domain sampling scheme to interpolate over the entire range of interest directly, and the second approach involves using a low-order (3-point) piece-wise interpolation scheme that only requires sampling in the spatial domain. The two methods are applied to a 0.5 meter dipole modeled from 150 to 950 MHz and from 0° to 90° in θ. This example is used to illustrate advantages and disadvantages in the use of both of these methods.