The one you use seems to be Wilkinson Power Splitter
EDIT
As per Wilkinson design, the splitter is designed for a frquency at which each side of top stripline (formig a square shape) is 1/4 wavelength. This means it will will work properly at or near that frequency only.
However the sellers are claiming it to be 100 Mhz to 2700 MHz 
. Well there is nothing to be surprised. Such over-blown Specs are usual at Ebay and Aliexpress. 