AntennaDesign.wikiAntenna design, explained

Which antenna should a LoRa device use?

From Antenna Design Wiki · By the · Published · Last reviewed · How we research

LoRa devices operate in sub-GHz bands defined regionally, including EU868 (863–870 MHz) and US915 (902–928 MHz).[1] A full-size λ/4 whip (about 8.6 cm at 868 MHz or 8.2 cm at 915 MHz) on an adequate ground gives the best device performance; compact helical, PCB and chip antennas trade efficiency for size. Gateways typically use vertical collinears mounted high.[2][3]

Why does the device antenna matter so much?

At 868–915 MHz, a small sensor board is electrically small, so efficiency of compact antennas can fall to 10–30%. Each 6 dB lost halves free-space range, and in practice battery life also depends on link margin through adaptive data rate.[4][5]

What power and gain limits apply?

In Europe, short-range device rules in EN 300 220 and the associated band plans specify ERP and duty-cycle limits per sub-band; the common 868.0–868.6 MHz sub-band allows 25 mW ERP with a 1% duty cycle.[2] In the US, 902–928 MHz digital modulation or hopping systems fall under 15.247 with 1 W conducted power and up to 6 dBi antenna gain before reductions.[3] Check the current regional parameters and rules for each deployment.[1]

How should gateways be installed?

Height dominates: raising a gateway antenna above local clutter extends line-of-sight coverage. Use low-loss coax, lightning protection and a collinear with gain matched to the coverage needed; very high gain narrows the elevation beam.[6]

Frequently asked questions

Can I use an 868 MHz antenna at 915 MHz?

Only if its bandwidth covers both; many are tuned for one band.

Is a helical stubby antenna adequate?

It works but usually costs several dB compared with a λ/4 whip.

Does the antenna need a ground plane?

Monopole-type antennas need one; dipoles do not.

References

Online sources accessed October 21, 2026; printed works cited by edition. See all sources.

  1. “LoRaWAN Regional Parameters (RP002)”. LoRa Alliance. current version.
  2. “ETSI EN 300 220: Short Range Devices operating in the frequency range 25 MHz to 1 000 MHz”. ETSI. current version.
  3. “47 CFR 15.247 — Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz”. U.S. FCC, eCFR. current text.
  4. “Modern Small Antennas”. K. Fujimoto and H. Morishita, Cambridge University Press. 2013.
  5. “A Note on a Simple Transmission Formula”. H. T. Friis, Proceedings of the IRE, vol. 34, no. 5, pp. 254-256. May 1946.
  6. “Antennas and Propagation for Wireless Communication Systems, 2nd ed.”. S. R. Saunders and A. Aragón-Zavala, Wiley. 2007.
Categories: Applications by band