A new equivalent circuit and physics-based analytical model have been developed for mm-Wave CMOS inductors simulation and design at various Si substrate resistivities (r_Si). This analytical model can accurately calculate self-resonance frequencies (f_SR) of on-chip inductors in TEM mode and eddy current mode associated with higher r_Si (10~1000 ohm-cm) and very low r_Si ≦0.1 ohm-cm. This equivalent circuit based model can facilitate simulation and design of miniaturized inductors aimed at super-100 GHz f_SR for application in mm-Wave or sub-THz CMOS circuits. Moreover, the f_SR can be boosted up to 548 GHz by sub-40pH inductor at r_Si ≧10 ohm-cm.