Better, More Compact Radio Frequency Devices Through 3D Printing

5G, the telecommunications advance that promises to carry more information at greater speeds, has an energy problem. 5G technology uses millimeter-wave transmission, a method that can precisely deliver data to specific phones or devices, but one that doesn’t inherently let that data penetrate through common objects like trees, walls or even the human body.

Radio frequency (RF) devices provide a solution, by sitting in front of the radiating elements or antennae to bend, focus and steer the RF energy toward its intended destination. RF lenses will be key to the proliferation of 5G communications, and producing capable devices quickly will be critical.

Conventional RF antenna lenses are made by fabricating layers of material of varying densities through layup. The method works, but can result in RF devices that are heavier, more complex and labor intensive to produce. Fortify, a maker of additive manufacturing technology for specialized applications, has established solutions for 3D printing complex RF geometries directly using high-performance resins created in collaboration with Rogers Corporation that are suited to the company’s Flux series of photopolymerization or digital light processing (DLP) 3D printers.

“We are able to control the waves through filler materials in the resin and the design of the lattice. Changing the density and gradient of the lattice can augment the beam pattern in various ways,” says Karlo Delos Reyes, cofounder of the company. 3D printed RF lenses are simpler to produce, can be more compact, and even offer performance improvements over conventional solutions. “These are low-loss devices, which makes the antennas more efficient,” Delos Reyes says.  

3 Keys to 3D Printing RF Devices

The RF devices I recently saw at Fortify’s Boston-area headquarters feature gyroid-based lattices that vary in unit size and density. Smaller unit cells achieve higher frequencies, and large ones suit lower frequencies. Those lattices, combined with tuning of the filler materials in the 3D printing process, can change the dielectric constant of the material and control radio waves through a compact device.

There are several keys to making this 3D printed RF solution work. They include:

1. The Radix material, a highly viscous resin developed in collaboration with Rogers Corporation. Like most materials used in Fortify Flux 3D printers, it consists of a base resin with filler materials to impart desired properties.
2. Fortify’s DLP platform with Continuous Kinetic Mixing (CKM), which makes it possible not only to print with viscous materials like the Radix resin, but to keep the additives inside properly dispersed throughout the entire printing process. “We can print with resins that are two to ten times more viscous than typical DLP resins,” Delos Reyes says.
3. Design software that is still in work (a beta launch is planned for later in 2023) to help customers translate RF simulations from current industry-standard software into 3D printable designs with minimal friction.

“An RF engineer doesn’t think in mechanical terms,” Delos Reyes says. “We want to make it as easy as possible for them to translate their work, and remove barriers to adoption.”

The solution is being used by a number of partners including Lockheed Martin (which is also an investor in Fortify) and private commercial telecom providers.

Empathy in Applications

Fortify’s entry into the radio frequency device space builds on past lessons learned in another niche: injection mold tooling. The company jointly developed a ceramic-reinforced polymer with Henkel that is suitable for rapid production of prototype and short-run injection molds. Customers using this solution for mold tooling are served by Fortify’s own team of injection molding specialists, employees who understand the pain points and concerns of these users.

“I hire most for empathy,” Delos Reyes says, citing the team of business development professionals, sales representatives and applications engineers that he leads. The approach is paying off in injection molding, illustrating how 3D printing can enter and advance an established industry.

Radio frequency is the next such area of focus for the company. Similar to its approach to mold tooling, Fortify has invested in R&D, industry-specific RF testing equipment, and personnel who can build bridges to current and potential customers interested in this solution.

This applications-first approach means that Fortify doesn’t see itself so much as an AM company, Delos Reyes says, but as a solutions provider diving deep into the niches it can serve.

“We try to avoid ‘shiny object syndrome’ and constantly going after the next cool thing,” Delos Reyes says. “For us, applications are the key to success in additive manufacturing.”