These are s-parameters given by simulation, NOT measured results. 

File name indicates conditions of the s-params.  There are three formats for the several files:

1) "ADRF6520_maxgain_flt_XXX.s4p" are s-params at maximum gain (~54 dB) for each filter corner & Bypass mode.  So for example, the file that reads 
"ADRF6520_maxgain_flt_144.s4p", are the s-params at maximum gain while the part is set to the 144 MHz filter corner.

2) "ADRF6520_vgn1_0_VGN2_0_flt_XXX.s4p" are s-params at minimum gain (~-6 dB) for each filter corner & Bypass mode.  So for example, the file that reads 
"ADRF6520_vgn1_0_VGN2_0_flt_144.s4p", are the s-params at minimum gain while the part is set to the 144 MHz filter corner.

3) "ADRF6520_vgn1_1p5_VGN2_0_flt_XXX.s4p" are s-params at max VGA1 and min VGA2 gain (~18 dB) for each filter corner & Bypass mode.  So for example, the file that reads 
"ADRF6520_vgn1_1p5_VGN2_0_flt_144.s4p", are the s-params at max VGA1 and min VGA2 gain while the part is set to the 144 MHz filter corner.