RF/Microwave homework

For a double stub tuner

Due to technological tolerances, the width of traces on printed circuit boards can deviate from the ideal

design. As the width of the transmission lines changes, the tuner frequency will shift and the minimum

reflection coefficient magnitude Γm will increase. Assuming that a maximum reflection coefficient

magnitude of Γm=0.2 is allowed at 2GHz, find the maximum percentage deviation allowed in the

transmission line widths.

I only need the equations that would relate Γm to width.