Designing and building radio frequency devices with tailored dielectric properties using additive manufacturing

• Published in: Microwave and optical technology letters Vol. 65; no. 3; pp. 777 - 784
• Main Authors: Oliveira Neto, Antonio M., Justo, João F., Beccaro, Wesley, Oliveira, Alexandre M.
• Format: Journal Article
• Language: English
• Published: New York Wiley Subscription Services, Inc 01-03-2023
• Subjects: 3D printing; Additive manufacturing; Antennas; antipodal Vivaldi antenna; Devices; dielectric gradient; dielectric lens; Dielectric properties; Filaments; Lenses; Manufacturing; Permittivity; Printers (data processing); Radio frequency; Ultrawideband
• ISSN: 0895-2477; 1098-2760
• DOI: 10.1002/mop.33571

This work presents a technique to produce radio frequency (RF) and microwave devices with relative permittivity (εr ${\varepsilon }_{{\rm{r}}}$) variations in specific locations. It is based on additive manufacturing, using two or more filaments, with different permittivities, which are introduced into the print head and mixed with designed proportions. While other techniques can vary the dielectric permittivity using air cavities along the object, our proposal allows varying permittivity without cavities, which provides devices with more stable properties. As an application of this technique in RF devices, a dielectric planar lens, with varying permittivity, was designed and built to work along with a planar Vivaldi antenna. The antenna plus lens system was experimentally measured, indicating gains of up to 1.98 dBi when compared to the system without the lens. It was also demonstrated that the lens has ultra‐wideband properties since it presented an increase in gain when compared to the reference one from 1.5 to 3.0 GHz.