STTR Phase I: Additive Manufacturing of Radio Frequency and Microwave Components from a Highly Conductive 3D Printing Filament

Period of Performance: 07/01/2017 - 06/30/2018


Phase 1 STTR

Recipient Firm

Multi3D LLC
434 Golden Harvest Loop Array
Cary, NC 27519
Firm POC, Principal Investigator

Research Institution

Duke University
2200 W. Main St, Suite 710
Durham, NC 27705
Institution POC


This STTR Phase I project will enable the rapid prototyping and manufacturing of radio frequency (RF) components with 3D printing, and thereby reduce component cost, weight, and turnaround time. The global RF components market is expected to reach $17.54 billion by 2022, but fabrication techniques for commercial RF components have seen little innovation. Conventional RF manufacturing techniques, such machining and photolithography, are accurate and reliable, but they are also expensive, time-consuming and produce unnecessary waste. 3D printing enables fast and accurate manufacturing of custom components, as well as the creation of extremely complex geometries at low-cost for improved component performance. 3D printing can also enable users to design components to fit the design space available, removing the necessity of designing technology around commercially available parts, a critical feature in space and weight-sensitive aerospace applications. However, the materials available to 3D printing are mostly limited to non-conducting polymers. By creating a highly conductive 3D printing material, and testing the properties of RF components made with this filament, this project will make it possible to rapidly prototype and produce custom RF components, thereby accelerating research and improving the competitiveness of RF component manufacturing in the U.S. This STTR proposal will create a highly conductive (>2×10^5 S m-1) polymer filament that can be used with low-cost fused deposition modeling 3D printers to create a variety of high-value RF components. The filament will be engineered to print reliably, and retain its conductivity and mechanical integrity to temperatures of ~150 °C. To achieve these goals, the proposed work will determine the relationship between conductivity, the loading of conductive filler, the shape of the conductive filler, the filament mechanical properties, and the viscosity of the filament at printing temperatures. New methods will be developed to prevent oxidation of the conductive filler at elevated temperatures. A novel conductive filler will be developed to achieve these performance specifications at low cost. Concurrent with these material development efforts, novel RF components will be designed, simulated, and printed in order to build a comprehensive database with detailed designs and printing parameters for producing the RF components with a low failure rate. By the end of this project, users will be able to design, predict, and reliably print RF components with conductive filament on low-cost 3D printers.