Convex envelopes of bivariate functions

Question

In order to convexify my nonlinear non-convex program I need convex envelopes for the function $(x/y)^2$, both x,y are positive. I am only aware of the convex envelopes of the type $xy$ from here https://optimization.mccormick.northwestern.edu/index.php/McCormick_envelopes. I also know that it is in general not possible to have an analytical expression of the convex envelopes for all functions. I would like to know how can I verify if there exists a convex envelope of for the mentioned function? If yes, what is it's analytical expression and how can I find it? If no, is there any other way to convexify such functions? Thanks in adavnce.