An antenna can be designed perfectly, manufactured perfectly and tested perfectly, and still fail in the field because the radome someone wrapped around it disturbed the pattern, attenuated the signal or detuned the resonance. Radomes look like packaging. They are in fact part of the antenna system, and they deserve the same engineering attention as the radiator inside.
Additive manufacturing is now a standard route to producing radomes for prototypes and low-volume production, particularly across the defence and unmanned systems sectors. Done well, AM radomes are excellent and shorten development cycles by months. Done poorly, they quietly undermine the very system they are meant to protect.
The material science bit
RF transparency depends on two material properties: dielectric constant and loss tangent. Lower values of both deliver cleaner signal pass-through. Among common AM polymers, PETG, ASA, unfilled PA and PEEK perform well across most defence-relevant bands. PETG-CF, PA-CF, any glass-filled material with significant content, and any metal-filled material are unsuitable. We catalogue suitable RF-friendly grades through OzFDM, so the material side of the decision is made before the print starts.
The implication is important. The same material library you would draw from for a structural bracket is mostly the wrong library for an RF radome. Material substitution at the workshop level, without re-checking the dielectric story, is not safe in this domain.
Wall thickness and layer strategy
Radome walls should be either electrically thin (well under a wavelength) or designed as a tuned half-wavelength wall at the operating frequency. Anything in between attenuates and distorts. For most VHF, UHF and SHF defence applications, an electrically thin wall in the range 1.5 to 3 mm is the practical choice.
Print orientation matters more than usual. Layer lines that run perpendicular to wave propagation create periodic dielectric variation that can act as a weak frequency-selective surface. Orienting layers parallel to the wave path mitigates this. It is the kind of detail that separates an RF-aware AM shop from a general-purpose printer.
Use PETG, ASA, unfilled PA or PEEK,
Avoid all carbon, glass and metal-filled grades,
Specify wall thickness against operating wavelength,
Orient layers parallel to RF propagation where possible,
Validate with a vector network analyser before deployment.
Mechanical and environmental demands
Radomes are structural items too. They must survive vibration, hail, UV, salt, fuel exposure in vehicle applications, and ballistic spalling in some hardened cases. ASA is the workhorse for outdoor radomes; PETG suits indoor or temporary use; PEEK is the premium choice for hot or chemically aggressive environments. External hardware like gaskets, fastener inserts and drainage features must be planned alongside the RF design, not bolted on later. Many radome failures in the field turn out to be mechanical, not electrical.
Validate before you deploy
The single most important step in AM radome work is end-to-end RF validation: print the radome, mount it on the production antenna, and measure pattern, gain and VSWR against the antenna alone. Anything more than 1 dB of insertion loss inside your operating band is a red flag worth investigating before the system reaches a platform.