A comparison of CAD models for the radiation from a rectangular microstrip antenna

Different radiation formulas are compared for the case of a rectangular microstrip patch antenna, either on an infinite substrate (Fig. la) or on an infinite ground plane with the substrate truncated at the boundary of the patch (Fig. lb). For both the infinite and truncated substrate cases the electric current model is compared with the magnetic current model using the dominant-mode assumption. A more exact radiation model is then developed which accounts for radiation from the probe and higher-order modes, and this is compared with the simpler dominant-mode models. A comparison will also made with measured results.