Embedded Active Elements in 3D Printed Structures for the Design of RF Circuits

This paper presents a simple, low-cost fabrication technique of RF components with embedded chips using additive manufacturing (3D printing). Three different approaches of embedding actives using 3D printing are discussed: (a) face-up, (b) face-down, and (c) use of flip chip. For the demonstration, tunable circuits using varactor diodes are designed and fabricated. Tunable microwave components such as a T-line resonator, a split ring resonator, and a patch antenna are demonstrated using the face-up embedded active process. Key advantages of this process are: (i) low temperature processing, (ii) use of wire -and ribbon-bonds can be avoided, and (iii) simple to implement. Embedded actives and passives using 3D printing provides a new approach to fabricating system on package (SoP) and system in package (SiP) having high functional density and better electrical performance.