Parametric analysis of angular inset-feed in circular microstrip patch antenna

This paper presents a parametric analysis of the use of angular inset-feed in different types of circular microstrip patch antennas, and its influence on the impedance matching of these structures. The proposed angular inset technique consists in make an opening in the conventional inset feed in order to improve the return loss (|S11| Parameter) and the impedance matching consequently. Also a modified expression is proposed for calculating the antenna input resistance having as reference the expression used for a conventional inset feed. It was simulated and measured antennas operating at frequencies of 1.4 GHz, 2.4 GHz and 5.0 GHz with good results. With the application of the proposed technique it was possible to obtain an improvement in the impedance matching of up to 33%. Numerical and experimental results are presented, being observed a good agreement between them.