This paper presents a parametric study of classical additive 3D-printing settings for use on conductive filaments in applications for high-frequency topologies. First, a wideband characterization was conducted, printing a microstrip transmission line using a conductive filament with variations of typical 3D-printing settings, such as layer height, infill percentage, and infill pattern. The measurement results show a dependence on the high-frequency transmission parameters with respect to the infill percentage and the infill pattern. Finally, two antennas were 3D-printed using conductive material, a microstrip patch, and a low-weight pyramidal horn antenna. The results for the patch agree with the losses found on the line measurements, while the low-weight pyramidal horn exhibits no major differences compared with its equivalent antenna, made using perfect conductors.

This article presents a fully 3D-printed dielectric planar lens operating in the entire Ka-band manufactured using additive manufacturing and a relatively low-cost 3D-printer. The lens consists of ten concentric rings implemented using low-loss ABS filaments with high permittivity values. By varying the infill percentages of them the required refractive indexes of each section are achieved. An additional 3D-printed matching layer, using the same manufacturing and design method was included in the lens, to reduce reflections. Simulation and measurement results show a very good agreement, which confirms the possibility of manufacturing a cost-effective broadband and planar lens solution operating in millimeter wave bands, where Low Earth Orbit Satellites (LEO) networks, future mobile communication systems (5G, 6G) and radar systems operate.

This article presents the design, construction, and evaluation of an easy-to-build textile pressure resistive sensor created from low-cost conventional anti-static sheets and conductive woven fabrics. The sensor can be built quickly using standard household tools, and its thinness makes it especially suitable for wearable applications. Five sensors constructed under such conditions were evaluated, presenting a stable and linear characteristic in the range 1 to 70 kPa. The linear response was modeled and fitted for each sensor individually for comparison purposes, confirming a low variability due to the simple manufacturing process. Besides, the recovery times of the sensors were measured for pressures in the linear range, observing, for example, an average time of 1 s between the moment in which a pressure of 8 kPa was no longer applied, and the resistance variation at the 90% of its nominal value. Finally, we evaluated the proposed sensor design on a classroom application consisting of a smart glove that measured the pressure applied by each finger. From the evaluated characteristics, we concluded that the proposed design is suitable for didactic, healthcare and lifestyle applications in which the sensing of pressure variations, e.g., for activity assessment, is more valuable than accurate pressure sensing.

In this letter, we propose and study a 2-D glide-symmetric dielectric periodic structure. We demonstrate that glide symmetry broadens the bandwidth of operation and achieves lower effective refractive indices when compared to non-glide configurations. These two properties are beneficial for producing graded-index lens antennas. To demonstrate the potential of the proposed unit cell, we designed a Luneburg lens operating in the K- and K $_\text {a}\!$ -bands. The lens was manufactured with conventional additive manufacturing and it has a potential use for future wireless communications given its low-cost and low-profile.

This article presents the design, construction and analysis of a 3D-printed transformed hyperbolic flat lens working on the 30 GHz band. The transformed lens was printed using only one ABS dielectric filament of relative permittivity of 12, varying the infill percentage of each transformed lens section in order to achieve the permittivity values obtained with the transformation optics. The 3D-printed hyperbolic transformed lens exhibits good radiation performance compared to the original canonical lens.

This article presents a parametric study of a fully 3D-printed hemispherical dielectric resonator antenna (DRA) using low loss dielectric filament and high-conductive filaments jointly with a low-cost customized dual-extruding 3D printer. The parametric study consisted in the design and evaluation of five different hemispherical DRA topologies with different internal shapes and the same overall size, in which the printing infill percentage of the DRA was reduced. A 3D-printed metallic cap was included in the antenna to compensate for the resonant frequency shift in order to maintain its original dimensions. Measurement results show that all evaluated antennas kept the same resonant frequencies and similar radiation patterns while reducing the overall weight of the topology in 22% of the nominal weight.