Multi-standard patch antenna based on stepped impedance microstrip

The paper has presents a study of the feasibility of designing a stepped impedance patch antenna (SIPA). We have developed a design method using two different models in order to process a global optimization on impedance matching and radiation requirements versus frequency. The aim of the method is to reduce the computational complexity that is a limiting factor in the optimization process. A circuit model based on a transmission line and discontinuities equivalent model gives the antenna impedance matching behaviour versus frequency; a radiation model based on a radiating slot line equivalent model of discontinuities gives the antenna radiation pattern shape versus frequency. A SIPA working at 1.01 GHz and 2.78 GHz has been designed on an FR4 substrate. Radiation patterns at both frequencies are quasi omnidirectional.