Compact double Meandered Line Inverted-F Antenna for outdoor parking wireless car detector

This paper presents a printed electrically small monopole antenna for outdoor parking wireless car detector. The system relies on a network of wireless sensors (one for each parking space) to transmit whether or not a space is occupied using the 868 MHz and 915 MHz ISM bands. In parking, the maximum distance separating two cars doesn´t exceed 5m. However, the wireless detector has to communicate with the base station at a maximum distance of 100 meters. The antenna is molded in silicon to protect the entire device from humidity. The bandwidth is broadened by inserting a U-slotted patch on the internal layer of the PCB board. Simulation results are presented which are in good agreement with measurement data. The system reading distance measurement shows good performance. We will describe in this paper how the antenna was designed and embedded in the system to fit the size and communication distance constraints.