I had fixed it and here is the solutions: if left and right only 1:1,then delta vbe is 0, so there's no current flows the resistance and it's why doesn't work.
So it should be keep K:1,K>=2, but the app can't work, you need add extra bjt without connection.
Vref=Vbe+kT/q * R1/R2 * ln(K), R2 left,R1 right!
