Antenna Design Wiki
Antenna Design Wiki is a sourced, vendor-neutral educational reference on antenna design. It explains how antennas radiate, the parameters that describe them (directivity, gain, efficiency, VSWR, polarization), the major antenna types, arrays and beamforming, matching, small and embedded antennas, simulation, measurement and regulations, with formulas checked against standard references such as Balanis and IEEE Std 145.[1][2]
Where should you start?
- What is an antenna?: An antenna is the transducer between guided waves on a transmission line and radiated electromagnetic waves in free space. Definition, parameters and types.
- What are the essential antenna formulas?: The essential antenna design formulas in one place: wavelength, directivity, gain, effective aperture, Friis, path loss, VSWR, return loss, far-field distance, Chu limit and arrays.
- What is an antenna radiation pattern?: A radiation pattern is the angular distribution of an antenna's radiated field or power in the far field. Main lobe, sidelobes, E- and H-plane cuts and normalization.
- What is antenna gain?: Antenna gain is directivity times radiation efficiency, G = e_cd·D. Realized gain also includes mismatch. dBi vs dBd, partial gain and how gain is measured.
- What are VSWR and return loss?: VSWR = (1+|Γ|)/(1−|Γ|) and return loss = −20 log|Γ| describe antenna match. Conversion table, mismatch loss, and what values are acceptable.
- What is a half-wave dipole antenna?: The half-wave dipole is a center-fed resonant wire about λ/2 long: about 73 Ω, 2.15 dBi directivity and 78° E-plane beamwidth. Length formula, feeding and variants.
- What is a patch antenna?: A microstrip patch antenna is a metal patch over a ground plane on a dielectric substrate, resonant when about λ_g/2 long. Feeds, gain (≈6–9 dBi), bandwidth and variants.
- What are inverted-F and planar inverted-F antennas?: The IFA and PIFA are quarter-wave antennas folded parallel to a ground plane with a shorting stub. How they work, resonance length, feeding, bandwidth and PCB design notes.
- What is a phased array antenna?: A phased array steers its beam electronically by controlling the phase (or time delay) of each element. Passive vs active arrays, architectures, scan loss and applications.
- What is the Chu limit?: The Chu limit gives the minimum radiation Q of an antenna enclosed in a sphere of radius a: Q ≥ 1/(ka)³ + 1/(ka) (McLean). Derivation, examples and implications.
- How do you match an antenna to 50 ohms?: How to match an antenna to 50 Ω: measure at the feed, then use L, pi or T networks, stubs or quarter-wave transformers. Design equations and worked example.
- How are antennas measured?: Antenna measurement covers impedance (VNA), radiation patterns, gain, efficiency and polarization in anechoic chambers, far-field, near-field and compact ranges, and OTA systems.
What are the essential numbers of antenna design?
- A half-wave dipole has about 2.15 dBi directivity and ~73 Ω radiation resistance.[1]
- A λ/4 monopole on an infinite ground has ~36.5 Ω and 5.16 dBi.[1]
- Free-space wavelength is about 300/f(MHz) meters; 2.4 GHz is about 12.5 cm.
- A 2:1 VSWR reflects 11% of power and costs 0.51 dB.
- The far field starts near 2D²/λ.[1]
- Free-space path loss is 32.45 + 20·log10 d(km) + 20·log10 f(MHz) dB.[3]
- Minimum Q of a small antenna is 1/(ka)³ + 1/(ka).[4]
How is the wiki organized?
Articles are grouped into fundamentals, antenna types, arrays and beamforming, feeding and matching, small and embedded antennas, applications by band, materials and radomes, simulation, measurement, regulations and safety, and propagation. See the contents, the glossary, the FAQ and the formula cheat sheet.
Frequently asked questions
What is this wiki?
An independent, sourced educational reference on antenna design, written by the Antenna Design Wiki editorial team.
Who is it for?
Students, engineers moving into antenna work from other fields, and practitioners who want a quick, sourced refresher.
How are facts checked?
Formulas and facts are checked against textbooks, IEEE standards and papers, ITU and FCC texts and manufacturer application notes.
See also
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 145-2013)”. IEEE Antennas and Propagation Society. 2014.
- “Recommendation ITU-R P.525: Calculation of free-space attenuation”. ITU-R. current edition.
- “A Re-examination of the Fundamental Limits on the Radiation Q of Electrically Small Antennas”. J. S. McLean, IEEE Transactions on Antennas and Propagation, vol. 44, no. 5, pp. 672-676. May 1996.