Antenna Array Based on 3D-printed Plastic BoR Elements Coated with Conductive Paint

Abstract

The body-of-revolution (BoR) Vivaldi arrays are usually all-metal, including both antenna elements and the antenna base. However, despite the robustness and low losses of the all-metal designs, they are often heavy and expensive. In this paper, we investigate 3D-printed, dual-polarized BoR antenna elements operating at 2-6 GHz. By 3D printing the antenna elements from plastic, we can make them less expensive, hollow, and thus lightweight. The elements are made conductive by painting them with silver paint. The performance of the antenna array is evaluated with simulations and measurements. Due to the relatively low conductivity of the paint, resistive losses of the array are higher than those of the all-metal counterparts. Nevertheless, the measured total efficiency of the array is still high, 95% at the highest, which confirms the applicability of the proposed manufacturing technique. Furthermore, we compare the proposed design to a previously published inverted BoR antenna array.

Performance Evaluation of a Low-Cost Semitransparent 3D-Printed Mesh Patch Antenna for Urban Communication Applications

“…This level of conductivity is sufficiently high to disregard dielectric and polarization effects, ensuring the continued validity of the approximation provided by Equation (2) [52]. According to this expression, the skin depth in this case is δ s = 14 µm, aligning with typical thicknesses for this type of metallic ink [37,38,47]. The antenna is well matched for smooth cases and for Rq values below 25 µm.…”

“…This is illustrated in Figure 12, where one of the semitransparent antenna models can be seen in Figure 12a, along with the result of printing semitransparent patch prototypes using different non-metallized materials in Figure 12b,c,d. This technique stands out for its relatively low cost compared to traditional manufacturing methods [37,38], as it minimizes material waste by building objects layer by layer, using only the precise amount of material required. Furthermore, 3D printing showcases an impressive diversity of available materials, ranging from plastics and resins to metals, ceramics, and even biodegradable materials, significantly expanding RF design possibilities and applications [39].…”

“…[40] ref [44] ref [45] ref [46] FDM PLA 0.12 mm Conductive paints and inks typically exhibit lower conductivity compared to the bulk material they contain [39]. Nevertheless, metallization using SCP has been successfully employed over the antenna in previous RF designs using methods such as airbrushing, paint-gun application, or manual brush application [37,38,47]. In this work, the antenna was hand-painted with a brush, applying a single layer on both sides of the conductive parts of the patch previously printed with dielectric filament.…”

“…For instance, in [47], a stretchable silver conductive paste was used, yielding a conductivity value of σ = 1.7 × 10 4 S/m for a paste layer with a thickness of 26.5 µm. Another hand-painted design is described in [38], where it was concluded that the manufacturer's nominal conductivity of the paint (σ = 1.3 × 10 6 S/m) did not significantly impact the antenna's efficiency in the measurement. However, the surface layer's conductivity was not experimentally characterized.…”