Physics-based compact lumped circuit model of PIFA using a retarded partial element equivalent circuit

This paper presents a physics based approach of developing a compact lumped circuit model of a narrow-strip printed inverted-F antenna (PIFA) using retarded partial element equivalent circuit (rPEEC) technique. The reduction in the rPEEC model size is achieved by assuming the potential to be uniform along the strip width, which is approximately λ/25, and by using non-uniform sub-gridding of capacitive and inductive cells to capture the charge and current discontinuity near the strip edge. In the proposed approach, the total number of lumped circuit elements is reduced by around 90% and the total number of nodes is reduced by nearly 65% at the cost of 1.037% change in the resonance frequency. Measurements show good agreement with rPEEC results.