Cascaded cylinder model for predicting terrain diffraction loss at microwave frequencies

The problem of determining the diffraction loss between a transmitter and receiver in clear air conditions, when the intervening terrain is given, is treated for propagation at microwave frequencies. A model is developed which simulates the terrain by means of a cascaded arrangement of cylinders. This model, which remains valid at grazing angles, extends Vogler´s result (1982) for cascaded half planes to treat cylinders. Experiments are conducted on two cylinders which share the same shadow boundary, for both vertical and horizontal polarisation. Measurements are performed on cylinders which present both zero and non zero surface impedance, and these are found to be in good agreement with predictions.