For the first time, a simple analytical model in the form of explicit formulas was derived for on-silicon-chip inductors. This analytical model can accurately calculate self-resonance frequencies (f(SR)) in TEM mode and eddy current mode corresponding to very high and very low substrate resistivities (rho(Si)). Furthermore, this derived model can predict and explain the interesting result that f(SR) keeps nearly a constant independent of rho(Si) in TEM and eddy current modes but is critically determined by the inductance and parasitic capacitances. The simple model is useful in on-silicon-chip inductor design for increasing f(SR) under specified inductance target for broadband RF circuit design and applications. (C) 2008 Elsevier Ltd. All rights reserved.