Effects of Cross Section Dimensions on Propagation Characteristics in Trapezoid Tunnel

The effect of cross section dimension on propagation characteristics in trapezoid tunnel is analyzed using finite element method. By varying the dimension of top side, bottom side, height, the cutoff frequency for dominant mode and the mode next to dominant and bandwidth in trapezoid tunnel are studied respectively. It comes to a useful conclusion that the increasing of top side, bottom side, height decrease the cutoff frequency and longer bottom side or lower height result in larger bandwidth.