A new excitation model for probe-fed printed antennas on finite size ground planes

This paper presents a new excitation model for probe-fed printed antennas on both infinite and finite size ground planes. The model has been developed within the general frame of the mixed potential integral equation (MPIE) and the method of moments (MoM). The technique is based on a delta-gap voltage model, and a special procedure is implemented inside the integral equation to effectively impose a voltage reference plane into a floating metallic plate which is acting as a ground plane. The present technique allows the accurate calculation of the input impedance of printed antennas, and the effects of finite size ground planes can be easily accounted for in the calculations. In addition, an efficient technique is presented for the evaluation of the radiation patterns of printed antennas, taking also into account the presence of finite size ground planes. Comparisons with measured results show that the new derived excitation method is indeed accurate, and can be used for the prediction of the backside radiation and side lobe levels of real life finite ground plane printed antennas.