Massachusetts-based 3D printer manufacturer Inkbit has unveiled gradient-index (GRIN) lenses produced through additive manufacturing (AM), designed for radio frequency (RF) and millimeter-wave (mmWave) systems and developed in partnership with the University of Delaware (UD). The components were presented at the IEEE International Microwave Theory and Technology Symposium (IMS), held June 7-12, 2026.
The announcement signals a change in how high frequency electromagnetic components are made: lenses that once required the assembly of multiple dielectric parts can now be printed as a single graded structure, at sizes and frequencies that earlier AM approaches did not reach.
Why GRIN lenses have been difficult to manufacture
Devices such as the Luneburg lens depend on a permittivity gradient that varies continuously across the component. Conventional production methods approximated this gradient by stacking discrete concentric dielectric shells, an approach that introduced signal losses, constrained how precisely permittivity could be tuned, and proved difficult to scale.
AM offered a route around the geometric problem, but earlier attempts came with trade-offs of their own. Printed lenses were generally confined to smaller electrical sizes or operated only across narrow bandwidths, falling short of what high frequency industrial applications require.
Pairing vision-controlled hardware with a low-loss resin
Inkbit’s approach combines its Vision-Controlled Jetting (VCJ) platform with a material developed specifically for RF use. VCJ relies on real-time computer vision to monitor and correct material deposition during printing, enabling the production of subwavelength lattice structures with tight geometric tolerances.
The lenses are printed in a Cyclic Olefin Thermoset (COT) resin engineered for dielectric performance. According to Inkbit, COT exhibits a loss tangent of 0.0018 at 100 GHz, which the company states is the lowest dielectric loss among additively manufacturable resins, alongside stable thermomechanical behavior. The combination allows graded lattice structures to direct electromagnetic waves with minimal attenuation.
Performance of the 100 mm Luneburg lens
The collaboration with the UD produced a 100 mm diameter Luneburg lens tested across the Ka-, U-, and W-bands, with operation reaching 100 GHz. The component has an aperture exceeding 30 wavelengths and a realized gain above 34 dBi. The findings were published in the SPIE journal Optical Engineering under the title “Fabrication and analysis of electrically large Luneburg lenses using vision-controlled material jetting.”
As passive beamforming devices, GRIN lenses operate without an external power supply and add little weight, positioning them as an alternative to active antenna arrays in applications where power budgets or mass are limiting factors. The geometry supports high directivity, broad angular coverage, and reduced sidelobe interference.
Jetting (VCJ). Image via Inkbit.
Target applications and availability
The technology is aimed at sectors moving toward mmWave frequencies, including telecommunications, aerospace, and defense. Potential use cases identified by the company include communications for autonomous drones, battlefield networks, satellite ground stations, and phased-array radars. The lenses’ data throughput capacity also makes them candidates for interconnects in artificial intelligence (AI) data centers, automotive radar, and industrial sensing arrays.
Inkbit is currently working on custom projects with industrial partners and has listed standard evaluation lenses for sale on its website, allowing engineering teams to test the components within their own RF workflows.
From assembled shells to single printed structures
The core of Inkbit’s strategy lies in collapsing what was once a multi-part assembly problem into a single print job. A Luneburg lens built from stacked dielectric shells inherits losses and tolerance errors at every interface, and the labor involved keeps unit costs high. Printing the full permittivity gradient as one continuous lattice removes those interfaces entirely — but doing so at apertures above 30 wavelengths and frequencies up to 100 GHz requires geometric precision and dielectric purity that earlier AM platforms could not deliver simultaneously. Inkbit’s bet is that VCJ’s closed-loop accuracy and the COT resin together clear both thresholds at once.
Previous efforts in the field illustrate where those ceilings sat. In 2021, Boston-based Fortify partnered with materials manufacturer Rogers Corporation to print Luneburg-style GRIN lenses in a single graded piece using digital light processing (DLP). The resulting Radix dielectric carried a loss tangent of 0.0043 — more than double the figure Inkbit reports for COT — and the lenses demonstrated were smaller in electrical size, typically targeting Ku- and Ka-band operation.
The UD’s own earlier work followed the same trajectory. In 2020, its researchers used fused deposition modeling to print Luneburg lenses as monolithic 5G components for the Ka-band, in collaboration with the U.S. Army. More recently, a University of California-led team printed 19 GHz antennas that cut weight by over 90% — confirming the single-piece approach, but at a fraction of the frequency now being claimed.
Each effort proved a piece of the concept. The result places Inkbit among the most capable commercially available additively manufactured Luneburg lens platforms reported to date.
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Featured image shows the 100 mm diameter Luneburg lens fabricated using Vision-Controlled Jetting (VCJ). Image via Inkbit.
