A Pattern Reconfigurable Antenna System Integrated in a Truck Side Mirror

Truck-to-Truck (T2T) communications possess an essential role in the field of vehicular communications and Intelligent Transportation Systems (ITS). The research investigations that are demonstrated in this paper involve the design, the development and the integration of an antenna array system inside a truck side mirror. A novel printed 3-element Electronically Switched Parasitic Array Radiator (ESPAR) antenna is presented, exhibiting pattern reconfigurability at 5.9 GHz (two directive beams, one omni-directional pattern). The measured reflection coefficient results indicate negligible deviations between the three antenna operating modes due to a switched impedance matching network that is embedded in the planar antenna structure. A system of two ESPAR antennas is enabled through a novel diversity scheme. An accurate integration approach of the two antennas in the upper part of the truck side mirror is proposed, implemented and experimentally verified, demonstrating an impedance bandwidth of 6.7% and a satisfactory pattern switching capability (3-4 dB gain increase between states).