Why A Wilkinson divider is an RF power splitter built from two quarter-wavelength transmission line sections of about 70.7 ohms (the geometric mean of 50 and 100 ohms), with a 100-ohm isolation resistor bridging the two output ports. It takes one 50-ohm input and delivers half the power to each of two 50-ohm loads, while the input still looks like 50 ohms. It is commonly used to feed stacked or phased antenna arrays from a single feed line, and the bridging resistor keeps the two outputs isolated from each other.
Watch out The choices about dividing frequency confuse the word "divider" with a digital frequency divider or prescaler; a Wilkinson divides power, not frequency. Matching a low-impedance source to a high-impedance antenna is the job of a transformer or matching network, not a splitter.
Wilkinson = power splitter, not frequency divider. One 50-ohm in, two 50-ohm outs, quarter-wave 70.7-ohm arms.