As the Microchip RN2483 currently seems to be the most popular integrated LoRaWAN modem on the market, it also has the best library support for the Arduino ecosystem. See also:
For submitting data to TTN, please have a look at:
This is based on the Microchip RN2483 as the “The Things Node” does. See also https://shop.thethingsnetwork.com/index.php/product/the-things-node/.
SODAQ has some RN2483 based hardware:
- “SODAQ ONE” a complete board with Cortex M0 and RN2483 onboard, unfortunately a bit too expensive with EUR 95
https://shop.sodaq.com/en/one-eu-rn2483-v2.html - LoRabee RN2483, XBee form factor, https://shop.sodaq.com/en/lorabee-rn2483.html