I recently start a collaboration with CongDuc Pham from Université de Pau on the design of a low-cost wireless terminal using LoRa technology.
The board integrate a LoRa transciever (RFM95 from HopeRF), an Arduino Mini Pro and a 868MHz antenna.
Promoting the University Cote d'Azur, the antenna structure is based on the use of the university acronym by smartly connecting the different letters together.
The presentation from CongDuc Pham @IWASI 2017 is available here.
The Arduino code for the board for end node and gateway can be found on CongDuc website
For a 14dBm Tx output power, i measure a total radiated power (TRP) of 12.7 dBm with a plastic casing (76% total efficiency).
The PCB is fabricated on a 0.8mm FR4 substrate. The total cost for components, board and battery is approximatly 10$.
More information can be found on this Github link : here.
C. Pham, F. Ferrero, M. Diop, L. Lizzi, O. Dieng, O. Thiaré, "Low-cost Antenna Technology for LPWAN IoT in Rural Applications", Proceedings of the 7th IEEE International Workshop on Advances in Sensors and Interfaces (IWASI'17), Vieste, Italy, June 15-16, 2017.