PEEC Modeling of Radiation Problems for Microstrip Structures

In this work, an accurate radiation model for the partial element equivalent circuit (PEEC) technique is introduced for modeling of microstrip structures. By making use of the concept of generalized complex inductance proposed recently for the free-space case, an accurate decomposition of the radiation resistance for a small dipole on microstrip substrate is derived for the first time using PEEC. Using the semi-analytical Green´s functions for microstrip substrates, the imaginary part of this complex inductance can be shown to represent a frequency-dependent resistance containing contributions from spatial radiations (spherical and lateral) and surface waves (cylindrical). Hence, depending on how the structure of interest is divided into meshes, an equivalent circuit network of “distributed” radiation resistances can be obtained. Two numerical examples have been carried out to validate the model. Results obtained are in good agreement with those from commercial full-wave electromagnetic (EM) solvers, showing the potential of the proposed model for representing high-speed/high-frequency microstrip structures and antennas in the network realm.