An efficient Integral equation-based electromagnetic propagation model for terrain

An improved fast integral equation (IE) method to evaluate the slow fading signal at 970 MHz over terrain is described here. An 11.1 km, two-dimensional, semi-rural terrain profile is modeled as a series of interconnecting perfectly electrically conducting (PEC) segments. The algorithm achieves its computational speed by approximating the local surface current as a constant-amplitude sinusoid. An appropriately scaled value of this current can be used to quickly compute the scattered field. This process takes 0.05 s on a PC with a 2.2 GHz Pentium 4 processor giving a standard deviation of 15.57 dB and 9.48 dB from the full-wave solution and measurements, respectively. Where the local surface current is modeled as having a Rayleigh distributed envelope the computation time is 2.66 s but a reduction in the standard deviation to 3.07 dB and 8.77 dB from the full-wave solution and measurements ensues.