(a)
(b)
Figure 2: In this figure, the height of the antenna is set to 20 m and the radius of the semiopen land is 2000 m. (a) shows propagation time delays of multipath signals produced by horizontal surfaces. The delay is only relative to the elevation angle of the direct signal. (b) shows propagation time delays of multipath signals produced by inclined surfaces. The delay increases by the distance and the absolute value of elevation angle .