Surface waves in urban propagation

Summary form only given. In urban propagation modelling, reflection is usually most important, followed by diffraction. Surface wave excitation by antennas near lossy building surfaces and their edges is known to occur but omitted. This is perhaps because its importance was unclear and because the mathematics to include it has been very inconvenient. A uniform asymptotic solution (R. Tiberio et al., 1993) applicable to this situation was provided by Professor Tiberio and colleagues a few years ago in two papers on line source scattering by a wedge with impedance faces. Numerical results for a right-angled wedge perfectly conducting on one face and with a lossy dielectric on the other were given. We have used this important advance to obtain numerical results for right-angled wedges with lossy dielectrics on both faces (H.D. Cheung and E.V. Jull, 2004). We also used complex dielectric constants obtained from experimental results in Manhattan (V. Erceg et al., 1992). These indicated H-polarization surface wave effects can be significant near building surfaces in the near field and also in the far field near specular reflection, whereas those for E-polarization are negligible. The situation for H-polarization near specular reflection is usually very important in urban propagation modelling and, when they are so prominent, surface wave effects need to be included. Some numerical results illustrating this and suggestions for further work are given