The concept of generalized complex inductance for the partial element equivalent circuit (PEEC) technique is introduced to model microstrip radiation problems. Using the semi-analytical Greens functions for microstrip substrates, the imaginary part of this generalized complex inductance can be shown to represent a frequency-dependent resistance containing information about the losses from spatial radiations (spherical and lateral) and surface waves (cylindrical). Hence, different radiation components can be derived separately, providing a useful and unique feature for representing high-speed/high frequency microstrip structures and antennas in the network domain.