The 902-928 MHz ISM segment spans 902 to 928 MHz and is used for us ism / lora / rfid. Wavelength at the center of this band is roughly 328 mm, which sets the physical size of every resonant element and, with it, the gain a given form factor can reach.
Why the band sets the antenna size
A half-wave dipole at the center of the 902-928 MHz ISM band is about 164 mm long, and a quarter-wave element about half that. Every practical antenna in this band is a variation on that dimension: a collinear omni stacks several half-wave sections to trade elevation beamwidth for gain, a panel places elements over a reflector, and a Yagi adds parasitic directors ahead of the driven element. There is no way to get more gain out of the same aperture, so a higher gain figure on this band always means a physically larger part.
This range is the practical sweet spot for wide-area coverage: enough diffraction and building penetration to serve a cell of several kilometers, with antennas that are still small enough to mount on ordinary hardware.
Band summary
| Frequency range | 902–928 MHz |
|---|---|
| Center wavelength | 328 mm |
| Half-wave element | 164 mm |
| Typical service | US ISM / LoRa / RFID |
| Catalog models | 139 |
Gain options on 902-928 MHz ISM
| Gain | Shortest model at that gain | Length | Elevation beamwidth |
|---|---|---|---|
| 2 dBi | AW-SPR0827-2 | 26 mm | 75° |
| 3 dBi | AW-FPC0827-3 | 55 mm | 90° |
| 4 dBi | AW-CMB-5-5GGPSWIFI | 150 mm | 55° |
| 5 dBi | AW-ID0827-5 | 185 mm | 30° |
| 6 dBi | AW-SCF0827-6 | 420 mm | 32° |
| 8 dBi | AW-FGS0827-8 | 1100 mm | 20° |
| 9 dBi | AW-WM0912-9 | 210 mm | 40° |
| 10 dBi | AW-PA7090-V10B120 | 720 mm | 30° |
| 11 dBi | AW-ID0827-11 | 295 mm | 55° |
| 12 dBi | AW-YG0890-12 | 465 mm | 40° |
| 15 dBi | AW-PA8090-V15B65 | 1300 mm | 15° |
| 18 dBi | AW-YG0890-18 | 1290 mm | 25° |
RFID Antennas models in this band
| Model | Band (MHz) | Gain | Polarization | Length | Connector |
|---|---|---|---|---|---|
| AW-PA8090-V18B65 | 806–960 | 18 dBi | Vertical | 2430 mm | N-Female |
| AW-PA8090-V15B65 | 806–960 | 15 dBi | Vertical | 1300 mm | N-Female |
| AW-PA8090-V12B65 | 806–960 | 12 dBi | Vertical | 700 mm | N-Female |
| AW-PA8090-X2x15B65 | 806–960 | 2x15 dBi | Dual ±45° slant | 1300 mm | N-Female |
| AW-PA7090-V18B65 | 698–960 | 18 dBi | Vertical | 2570 mm | N-Female |
| AW-PA7090-V15B65 | 698–960 | 15 dBi | Vertical | 1360 mm | N-Female |
| AW-PA7090-V12B65 | 698–960 | 12 dBi | Vertical | 720 mm | N-Female |
| AW-PA8025-H12B65 | 806–2500 | 12 dBi | Horizontal | 660 mm | N-Female |
| AW-PA8025-V12B65 | 806–2500 | 12 dBi | Vertical | 660 mm | N-Female |
| AW-PA7090-V11B90 | 698–960 | 11 dBi | Vertical | 720 mm | N-Female |
| AW-PA7090-V10B120 | 698–960 | 10 dBi | Vertical | 720 mm | N-Female |
| AW-WM0912-9 | 902–928 | 9 dBi | Vertical | 210 mm | N-Female |
Matching the band to the link
Free-space loss at the center of this band is about 92 dB over one kilometer. Add the loss of the feedline, subtract the gain at both ends, and compare the result against the receiver sensitivity for the modulation you intend to run. If the margin is under roughly 10 dB the link will work on a clear day and drop in rain or foliage, which is usually the point at which a higher-gain aperture or a shorter cell radius becomes the cheaper fix.