Design and Manufacturing of Super-Shaped Dielectric Resonator Antennas for 5G Applications Using Stereolithography

Abstract

In this work, the inverted micro-Stereolithography (SLA) is used to show the potential of such additive manufacturing (AM) technology at prototyping super-shaped dielectric resonator antennas (S-DRAs) rapidly and accurately. The S-DRAs, which exhibit 3D complex geometries, were designed to operate at 3.5 GHz, suitable for the assessment of 5G communications in the mid band. Initially, a cross-starred-shaped S-DRA was designed and manufactured via the inverted micro-SLA by means of a photopolymer resin as material. As no information about the used material was available from literature and supplier, the dielectric properties of the photopolymer resin were characterized. Moreover, in the view of challenging further the SLA capability, several prototypes, based on the cross star shaped geometry but exhibiting a twist of variable angles along the longitudinal axis, were fabricated and tested. In order to compare the antennas performance in relation to the material volume and sizes, rectangular and cylindrical DRAs were also realized using same material and technology. Scattering parameter S 11 , gain, bandwidth (BW), efficiency and co-and cross-polarization of all antennas were measured. The experimental results showed that twisted S-DRAs exhibit same performance of the basic cross-starred-shaped antenna, due to the invariance to symmetry of the basic Gielis geometry. The measured gain is about 2.5 dB over a range of 1 GHz in the frequency range of interest; the BW measured for all S-DRAs is about 10%, whereas the efficiency is about 80% at 3.5 GHz. Finally, better performance in terms of bandwidth is shown by the S-DRAs, considering their dramatic volume reduction (∼85%) compared to classic rectangular and cylindrical DRAs and other DRA examples already reported in the state of the art.

Rapid Prototyping of Bio-Inspired Dielectric Resonator Antennas for Sub-6 GHz Applications

“…Nonetheless, a slight asymmetry in the main lobes was detected for the DRAs: this trend is in line with the simulated results that Melchiorre et al reported [34]. Finally, in order to highlight the benefits of exploiting bio-inspired geometries on antenna performance, the comparison between the experimental results concerning some examples of planar antennas and DRAs having various shapes is reported in Table 4: in particular, circular and modified bio-inspired patch antennas [1], regular rectangular Finally, in order to highlight the benefits of exploiting bio-inspired geometries on antenna performance, the comparison between the experimental results concerning some examples of planar antennas and DRAs having various shapes is reported in Table 4: in particular, circular and modified bio-inspired patch antennas [1], regular rectangular patches made with different metals [3], classic rectangular and cylindrical DRAs [26], starshaped DRA [26], and the proposed SsDRA, made with the same photopolymer resin, were considered. All data refer to the frequency range of interest, 2-6 GHz.…”

“…As a matter of fact, several dielectric materials are suitable for use in AM technologies, although few of them have actually been evaluated and characterized in the microwave range. Among polymers, the thermoplastic Poly-Lactic Acid (PLA) [ 23 , 24 , 25 ] and, more recently, photopolymer resins [ 26 ], have been analyzed, characterized, and utilized.…”

3D‐printed ceramics with engineered anisotropy for dielectric resonator antenna applications

“…Finally, we choose the value of a for which f 2 and Q 2 best satisfy Equation (3). Similarly, by means of Equations ( 4)-( 6), from a list of discrete possible values, we choose the value of ε x for which f 1 and Q 1 best satisfy Equation (2).…”

“…If the fabrication of heterogeneous DRAs with complex shapes has so far been limited by traditional manufacturing methods such as tooling, machining, or moulding, recent advances in three‐dimensional (3D)‐printing technologies are opening up new perspectives. Complex shapes have thus been achieved such as super‐shaped DRAs based on photopolymer stereolithography apparatus (SLA) [2], or even full DRA reflectarrays manufactured using the fused deposition modelling (FDM) printing technique [3]. It has also been proposed to control the effective permittivity of DRAs by structuring the 3D‐printed material.…”

Surface Mountable Multiband Dielectric Resonator Antenna for Wireless Communication Systems

“…Employing higher-order modes in conjunction with fundamental modes to achieve multiple resonances in dielectric resonators is communicated in [3]. Various shapes of dielectric material have been proposed to achieve multiband characteristics in [4][5][6][7][8]. Stacking of dielectric resonator materials to attain multiple bands has been discussed in [9][10][11].…”