How are antennas measured?
Antenna measurement determines impedance (with a vector network analyzer), and radiation patterns, gain, efficiency and polarization on an antenna range: an outdoor or indoor far-field range, a compact range, or a near-field scanner, usually inside an anechoic chamber. IEEE Std 149 is the recommended practice for these measurements.[1]
What gets measured?
| Quantity | Typical method |
|---|---|
| Input impedance, S11, isolation | VNA |
| Radiation pattern (co/cross-pol) | Far-field, compact or near-field range |
| Gain | Gain transfer or three-antenna method |
| Efficiency | Pattern integration, Wheeler cap, reverberation chamber |
| TRP, TIS, EIRP of devices | OTA systems |
What are the main error sources?
- Reflections from chamber walls and fixtures (quiet-zone quality).
- Insufficient range length (phase error) or probe correction errors.
- Cable effects and common-mode currents on small DUTs.
- Positioner alignment, polarization alignment and drift.
- Reference antenna calibration uncertainty.[1][2]
How should a small embedded antenna be measured?
Measure in the final device or a faithful mock-up, feed with a thin cable dressed with ferrite chokes or use the device’s own radio, and prefer TRP/TIS or efficiency measurements over gain at one angle, because embedded antennas are rarely used at a single direction.[3][1]
Frequently asked questions
Which standard covers antenna measurement?
IEEE Std 149, Recommended Practice for Antenna Measurements.
Do I need an anechoic chamber?
For accurate patterns and efficiency, yes, or an outdoor range; impedance can be measured on a bench.
What is a quiet zone?
The region where the test field approximates a plane wave with acceptable ripple.
See also
References
Online sources accessed October 21, 2026; printed works cited by edition. See all sources.
- “IEEE Recommended Practice for Antenna Measurements (IEEE Std 149-2021)”. IEEE Antennas and Propagation Society. 2022.
- “An Overview of Near-Field Antenna Measurements”. A. D. Yaghjian, IEEE Transactions on Antennas and Propagation, vol. 34, no. 1, pp. 30-45. January 1986.
- “Test Plan for Wireless Device Over-the-Air Performance”. CTIA Certification. current version.