How are antennas measured?

From RF Design Wiki · By the RF Design Wiki editorial team · Published October 21, 2026 · Last reviewed October 21, 2026 · How we research

Antenna patterns, gain and efficiency are measured in far-field ranges, anechoic chambers lined with RF absorber, compact ranges that use a reflector to create a plane wave, or near-field scanners that sample fields close to the antenna and transform them mathematically to the far field. Gain is commonly found by substitution against a calibrated reference antenna.^[1]^[2]

How is gain measured?

In the substitution method, received power with the antenna under test is compared with that of a standard-gain horn of known gain at the same position: G_AUT = G_ref + P_AUT − P_ref (dB). The three-antenna method solves Friis equations for three unknown antennas without a reference.^[1]

How is radiation efficiency measured?

By integrating total radiated power over a sphere in a chamber and comparing with accepted power, or with the Wheeler cap method for small antennas, which compares input resistance with and without a conducting cap enclosing the antenna.^[3]

What is OTA testing?

Over-the-air testing measures complete devices, including TRP (total radiated power) and TIS (total isotropic sensitivity), in chambers following procedures such as those from CTIA and 3GPP. It captures the effect of the enclosure, user and self-interference.^[4]

Frequently asked questions

Why use near-field scanning?

It allows large or high-frequency antennas to be measured in compact facilities.

What is a quiet zone?

The region in a chamber where reflections are low enough for accurate measurement.

Is return loss enough to qualify an antenna?

No; an antenna can be well matched and still inefficient.

References

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

“Antenna Theory: Analysis and Design, 4th ed.”. C. A. Balanis, Wiley. 2016.
“IEEE Standard for Definitions of Terms for Antennas (IEEE Std 145)”. IEEE. 2013 revision.
“Fundamental Limitations of Small Antennas”. H. A. Wheeler, Proceedings of the IRE, vol. 35, no. 12, pp. 1479-1484. December 1947.
“3GPP TS 38.101-1: NR; User Equipment (UE) radio transmission and reception; Part 1: Range 1 Standalone”. 3GPP. Release 17 and later.

Categories: Test and measurement

Articles on RF Design Wiki

Start here	Main page What is RF design Learning path Design workflow
Fundamentals	Decibels and dBm RF power Wavelength and frequency Thermal noise Noise figure Noise temperature SNR and Eb/N0 Skin effect Q factor Nonlinearity and harmonics Intermodulation and IP3 P1dB compression Dynamic range and SFDR
Transmission lines	Transmission line theory Characteristic impedance Γ, VSWR and return loss Input impedance of a line Quarter-wave transformer Microstrip Stripline Coplanar waveguide Coaxial cable Waveguides RF connectors
Matching and S-parameters	Impedance matching Maximum power transfer Smith chart L-network matching Pi and T networks Stub matching Bode–Fano limit S-parameters Touchstone files Z, Y, ABCD parameters De-embedding Mixed-mode S-parameters
Filters and passives	RF filter basics Filter approximations LC filter design Microstrip filters Cavity and dielectric filters SAW and BAW filters Diplexers and duplexers Wilkinson divider Couplers and hybrids Baluns Circulators and isolators RF attenuators Passive components
Amplifiers	Gain definitions Amplifier stability LNA design Power amplifier basics PA classes Efficiency and PAE Doherty amplifier Linearization and DPD Load-pull Transistor technologies Transistor biasing ACPR and EVM
Mixers and frequency generation	RF mixers Mixer specifications Image frequency I/Q modulators Oscillator basics Crystal oscillators VCO design Phase noise Jitter from phase noise PLL basics PLL loop filter Fractional-N synthesis Direct digital synthesis Multipliers and dividers
Antennas and propagation	Antenna fundamentals Gain and directivity Dipole antenna Monopole antenna Patch antenna Arrays and beamforming Small antenna limits Polarization Friis equation Free-space path loss Link budget Multipath and fading Atmospheric and rain loss Path loss models Fresnel zones
Receivers and systems	Receiver architectures Superheterodyne Direct conversion Low-IF receiver Software-defined radio Receiver sensitivity Blocking and selectivity Transmitter architectures Modulation ADCs for RF Radar basics
PCB layout and materials	RF PCB layout RF PCB materials Grounding and vias Controlled-impedance stackup Decoupling RF shielding Thermal design
EMC and EMI	EMC and EMI basics FCC Part 15 CISPR standards Immunity and ESD EMI filters and ferrites Precompliance testing RF exposure limits
Test and measurement	Vector network analyzer VNA calibration Spectrum analyzer Noise figure measurement Phase noise measurement RF power measurement Signal generators TDR Antenna measurement Oscilloscopes for RF
Simulation	Simulation overview Harmonic balance EM simulation EM solver methods SPICE for RF
Standards and bands	Frequency bands Radar band letters ISM bands 5G NR bands Wi-Fi and Bluetooth RF GNSS frequencies Amateur radio bands Spectrum regulation
Reference	Formula cheat sheet Textbooks and references Glossary FAQ All sources
About	About Editorial policy