Design and development of pattern reconfigurable antennas for vehicular environment

Abstract

Recently the pattern reconfigurable antennas are attracting greater attention as they are useful for systems that suffer from fading and multipath interference. These reconfigurable antennas radiate in the intended direction which makes the network avoid interference from noise sources. This provides a higher Signal to Noise Ratio (SNR), better diversity gain with the larger data rate. On account of its pattern selectivity, the pattern reconfigurable antenna is capable of enhancing system security, improving communication reliability and reducing energy loss to improve the overall performance of vehicular communication. The design of a pattern switchable patch antenna for vehicular applications is presented. The proposed antenna has a square patch that is divided into four triangular regions using diagonal rows of vias. The triangular regions are separately excited using a coaxial feed to achieve frequency and pattern reconfiguration. Each triangular section of the antenna has U shaped and inner rectangular strips to obtain two resonant frequencies of 2.4 and 3.5 GHz, respectively to cover the part of WLAN, WiMax, and car-to-car communication ranging from 3.4 to 3.8 GHz. In order to cover the maximum bandwidth of WLAN and WiMax standards, frequency tuning is done using a varactor diode. Upon exciting any one of the port, the antenna generates a tilted beam with a peak gain of 6.8 and 5.8 dBi at 2.45 and 3.5 GHz, respectively. A full azimuth beam coverage can be achieved by exciting the ports sequentially. The antenna is also capable of generating eight other beams using multiple feed excitations with the maximum gain of 8.4 and 9.4 dBi for the axial beam at 2.45 and 3.5 GHz, respectively newline