Higher Order Modes: A Solution for High Gain, Wide Band Patch Antennas for Different Vehicular Applications

Low-gain and narrow bandwidth problems are associated with patch antennas, and due to their inverse relation with each other, these problems cannot be improved simultaneously. It is well understood that the patch antenna excited at the higher order modes (HOMs) can overcome the problems of low gain and narrow bandwidth, provided that the modes are excited properly. For a given geometry, all the resonant frequencies are related in fixed ratios, providing no flexibility for the designer. Furthermore, high side lobe levels and undesirable radiation patterns are associated with the higher order modes. The excitation of higher order modes in given dimensions of the patch is achieved by surface modification and loading of slots on the patch. Two antennas based on a novel design procedure are discussed in the Ku and Ka bands to validate the proposed facts. The antenna in the Ka band has a peak gain of 8.5 dBi with 15.14% of bandwidth, while the one in the Ku band has a peak gain of 11.84 dBi with 17.6% of bandwidth. The design procedure is particularly important in designing antennas for applications like mobile satellite communication, wideband and multimedia applications, collision avoidance systems in vehicles, etc.