The Yagi antenna is tuned to a 200 MHz bandwidth @ VSWR ~1.8:1 from 690 to 890 MHz. This allows the one high gain antenna to operate on both 850 MHz 3G and 700 MHz 4G without any major compromise in performance. Once the 3G network has been shut off the antenna will then provide connectivity over the 5G NR850 network which will take its place.
With a 13 to 14 dBi gain, the antenna is designed to operate in rural and regional areas, out to about 40 kilometres from the nearest base station. This gain provides a good compromise between high gain and narrow beamwidth. Antennas need to maintain a reasonably wide beam (around 25 degrees in this case) to capture reflected and delayed radio paths that your device can digitally reconstruct.