Characterization of additively manufactured cellular alumina dielectric structures

Additive manufacturing (AM, also known as 3D printing) can produce novel three-dimensional structures using low-loss dielectric materials. This enables the construction of dielectrics with complex shapes that enable innovative microwave applications such as resonators, filters, and metamaterial lenses. This paper addresses the production and characterization of cellular structures of various designed densities created with a low loss ceramic material, alumina (aluminum oxide), via vat photopolymerization. The permittivity of these printed structures is variable over roughly an octave, with a range of relative permittivites from 1.78 to 3.60, controlled via part geometry.

1 Introduction

Additive manufacturing (AM) is known for its ability to produce structures that are impossible to create via traditional manufacturing processes such as subtractive machining and casting. Structures with designed internal voids, inaccessible from the exterior of the structure, known as cellular structures, in particular can be easily produced via AM, and such structures can be used to create designed dielectric materials [1], [2]]. Designed dielectric structures have potential applications as elements of dielectric waveguides, high performance antenna substrates, elements of high frequency high-Q analog electronic filters and resonators, and high temperature sensors.