In this paper, the link budget of the multiband UWB channel is studied based on empirical analysis of path loss and shadow fading by dividing the frequency range into multiple sub- bands with 500 MHz bandwidth. The work is based on ultra- wide band (UWB) propagation measurements performed in two indoor environments of a hall and a corridor in the frequency range of 3-10 GHz. It is found that in the multiband channels, the path loss exponent is independent on frequency, and the mean path loss can be modelled as a function of frequency. Shadowing (in dB) fits well with normal distribution, and the standard deviation (STD) of shadowing shows a tendency of increasing with frequency. Furthermore, the shadow fading margin with 90% link success probability is found to bee fairly low (less than 4 dB) the multiband channels. The presented results can be used for design of UWB radio systems.