How do you design an antenna radome?
A radome is a protective cover that must be electrically transparent at the antenna’s frequencies. Designs use either a thin wall (much less than a wavelength thick in the material), a half-wave wall whose thickness d = nλ0/(2√(εr − sin²θ)) cancels reflections at incidence angle θ, or sandwich constructions such as the A-sandwich of two dense skins around a low-density core.[1][2]
Why does a radome affect the antenna?
Every dielectric interface reflects; reflections reduce transmission, raise sidelobes, shift beam pointing (boresight error) and detune nearby antennas. Absorption by lossy materials and water films further reduces gain, a serious effect at Ka-band and above.[1]
Which materials are used?
Glass- and quartz-fiber composites with epoxy, cyanate ester or PTFE matrices, polycarbonate and ABS plastics for consumer devices, foam cores in sandwiches, and ceramics for high-temperature missile radomes. Low εr and tan δ and stable properties over temperature and moisture are desired.[1]
How close can a radome be?
Placing a radome in the antenna’s reactive near field detunes it like an enclosure; spacing of a fraction of a wavelength, or designing antenna and radome together in simulation, is standard. Automotive radar bumpers are designed as radomes at 76–81 GHz.[1][3]
Frequently asked questions
What is a half-wave wall at normal incidence?
Thickness d = λ0/(2√εr); for εr = 4 at 10 GHz that is about 7.5 mm.
Do wet radomes lose more?
Yes; water films can add several dB of loss at high frequencies, so hydrophobic coatings are used.
What is boresight error?
Shift of the apparent beam direction caused by the radome, critical for tracking radars.
See also
References
Online sources accessed October 21, 2026; printed works cited by edition. See all sources.
- “Analysis of Radome-Enclosed Antennas, 2nd ed.”. D. J. Kozakoff, Artech House. 2010.
- “Antenna Engineering Handbook, 4th ed.”. J. L. Volakis (ed.), McGraw-Hill. 2007.
- “47 CFR 15.253 — Operation within the band 76-81 GHz”. U.S. FCC, eCFR. current text.