We investigate the characteristic of microlensing signals of Earth-like moons orbiting ice-giant planets .
From this , we find that non-negligible satellite signals occur when the planet-moon separation is similar to or greater than the Einstein radius of the planet .
We find that the satellite signal does not diminish with the increase of the planet-moon separation beyond the Einstein radius of the planet unlike the planetary signal which vanishes when the planet is located well beyond the Einstein radius of the star .
We also find that the satellite signal tends to have the same sign as that of the planetary signal .
These tendencies are caused by the lensing effect of the star on the moon in addition to the effect of the planet .
We determine the range of satellite separations where the microlensing technique is optimized for the detections of moons .
By setting an upper limit as the angle-average of the projected Hill radius and a lower limit as the half of the Einstein radius of the planet , we find that the microlensing method would be sensitive to moons with projected separations from the planet of 0.05 { AU } \lesssim d _ { p } \lesssim 0.24 { AU } for a Jupiter-mass planet , 0.03 { AU } \lesssim d _ { p } \lesssim 0.17 { AU } for a Saturn-mass planet , and 0.01 { AU } \lesssim d _ { p } \lesssim 0.08 { AU } for a Uranus-mass planet .
We compare the characteristics of the moons to be detected by the microlensing and transit techniques .