Ultra High Frequency Circuit Identification through Gene Expression Programming

Abstract

The characterization of linear electrical components for frequencies up to a few MHz can be performed through impedance spectroscopy techniques that include the determination of the impedance frequency response and the algorithms that identify the equivalent circuit components. However, at higher frequencies some extra challenges are present since it is not practical to measure the impedance frequency response and s-parameters must be used. Although the conversion between s-parameters and equivalent impedance is well known, the application of the circuit identification algorithms is not straightforward. This paper presents a new procedure to perform circuit identification, through impedance spectroscopy, for components that operate at UHF. The s-parameters are measured and the equivalent circuit is obtained by using evolutionary algorithms, namely genetic algorithms and gene expression programming. The procedure is validated through experimental characterization of an RFID device.