The first fully functional prototype of the PROLONG receiver has been assembled.
The prototype is printed on a low-cost ready for mass production 0.8 mm thick FR4 substrate. It integrates the dual-band GNSS receiver (ArduSimple simpleRTK2Blite), two LoRa transceivers supporting operation at both 868 (Microchip RN2483A) MHz and 2.4 GHz (NiceRF SX1280), and a Raspberry Pi Zero acting as the main controller. Each transceiver is connected to a dedicated antenna subsystem ensuring energy-efficient wireless communication of the GNSS and LoRa signals. More specifically, the antenna subsystem is constituted of three different antennas: a LoRa 868 MHz slot antenna, a GNSS dual-band antenna, and a LoRa 2.4 GHz Inverted-F antenna.
The design of the three radiating elements has been done by carefully considering the integration constraints and the presence of the other electronic components (transceivers, microcontroller, batteries, etc).
Moreover, the position of the antennas on the PROLONG receiver has been optimized to maximize the antenna radiation efficiency at the working frequencies and to minimize the interferences.