Info about the '.dat' files:

In the archive, there is a separate '.dat' file for each radar frequency and 
shape type. 

In each line in the fractal-data files, there are the maximum diameter (mm), 
sample number (1-50), fractal parameter number (1-4) corresponding to number of 
iterations N_iter (5-8), co-polarized horizontal backscattering cross section (m^2), 
co-polarized vertical backscattering cross section (m^2), and the 
cross-polarized backscattering cross section (m^2). 

In each line in the aggregate-data files, there are the maximum diameter (mm), 
sample number (1-10), aggregate number (1-10) corresponding to the number of 
crystals in the aggregate (10, 20, 30, 40, 50, 60, 70, 80, 90, and 100), co-polarized 
horizontal backscattering cross section (m^2), co-polarized vertical backscattering 
cross section (m^2), and the cross-polarized backscattering cross section (m^2). 

Info about the DDA computations:

All computations were carried out with the publicly available ADDA software 
(http://code.google.com/p/a-dda/). In each dipole shape file, there are
the integer coordinates of each dipole in X, Y, and Z-directions. The dipole 
spacing used is 46.875 micrometers. The filtered coupled dipoles is used to
specify the polarizabilities. For the S- and C-bands, the incident wave is 
propagating along the positive X-axis, while for the Ku-, Ka-, and W-bands, 
along the positive Z-axis. The refractive indices used are according to Maezler 
(2006):

S-band (2.7 GHz):   m=1.7844+i0.0001
C-band (5.6 GHz):   m=1.7844+i0.0001
Ku-band (13.6 GHz): m=1.7844+i0.0003
Ka-band (35.6 GHz): m=1.7844+i0.0008
W-band (94.0 GHz):  m=1.7844+i0.0021

All computations were performed in fixed orientation.