# A 3D-Printed Enclosed Twist Dielectric Resonator Antenna with Circular Polarization
## 4 Antenna Manufacturing Using 3D Printing  
The antenna was manufactured using a Creality CP-01 printer and using the AVIENT ABS1500 filaments, with a relative permittivity of \(\varepsilon_{r}=15\) and a loss tangent of \(\tan\delta=0.0010\). The printing parameters used for this implementation are shown in Table 1.  
One notable advantage of this antenna design is its manufacturability in a single print, achieved by adjusting the infill percentage during the printing process. By varying the infill, the design enables the controlled tuning of the relative permittivity without the need for multiple fabrication steps or additional materials. For this specific implementation, a low infill percentage was used within the outer box of the antenna to minimize material usage while still meeting the functional requirements.  
To assess the dielectric properties of the printed material under actual fabrication conditions, a characterization process was conducted, considering the tolerances and limitations inherent to the printer. This characterization was performed using the Nicolson-Ross-Weir (NRW) method [25], which provides an effective way to measure complex permittivity values across a defined frequency range. Test samples were analyzed within the frequency range of 4.8 GHz to 7 GHz using a WR159 waveguide setup.  
Through this method, the measured relative permittivity of the ABS1500 material was found to be \(\varepsilon_{r}=13\) when printed with a 100% infill density, utilizing the same printer and parameters outlined in the design. These measurements confirm that, while the manufacturer specifies a relative permittivity of 15, variations in printing parameters can significantly impact the dielectric properties of the material, emphasizing the importance of in situ characterization for precision applications in high-frequency designs.  
As previously described, two different permittivity values were used for the different components of the antenna. To realize this variation in permittivity while using only a single type of filament, two different infill percentages were applied, as indicated in Table 1. By modifying the infill percentage, we effectively altered the density of the material, which in turn adjusts its dielectric properties.  
The slicing software UltiMaker CURA 5.7.1 was used to implement these varying infill percentages. Figure 11(a) illustrates the CURA interface, where different infill percentages are assigned to the different antenna regions. The final, fully fabricated antenna can be seen in Figure 11(b). In this we can see, just for visualization, the different sections of the antenna. First, we see a printed version of the twist without the box, which shows how the printer implements the main radiating structure. Then, there is a version where we can see both the box and twist in the same printing process in order to confirm the compatibility of the printing process and, finally, the full enclosed twist structure. This approach not only simplifies the manufacturing process by using a single filament type but also enhances material efficiency and design flexibility, ensuring that the antenna meets  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value** \\ \hline Printing Temperature & 260 \({}^{\circ}\)C \\ \hline Build Plate Temperature & 90 \({}^{\circ}\)C \\ \hline Printing Speed & 20 (mm/s) \\ \hline Flow & 100\% \\ \hline Infill Percentage Twist & 100\% \\ \hline Infill Percentage Box & 10\% \\ \hline \hline \end{tabular}
\end{table}
Table 1: Printing parameters.  
specific performance requirements without the need for additional materials or complex assembly procedures.