Article
The Use of 3D Printing Technology for Manufacturing Metal
Antennas in the 5G/IoT Context
Diogo Helena
1
, Amélia Ramos
1,2
, Tiago Varum
1,
* and João N. Matos
1,2
Citation: Helena, D.; Ramos, A.;
Varum, T.; Matos, J.N. The Use of 3D
Printing Technology for
Manufacturing Metal Antennas in the
5G/IoT Context. Sensors 2021, 21,
3321. https://doi.org/10.3390/
s21103321
Academic Editor: Ángela María
Coves Soler
Received: 24 March 2021
Accepted: 7 May 2021
Published: 11 May 2021
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4.0/).
1
Instituto de Telecomunicações, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal;
diogo.helena@ua.pt (D.H.); ameliaramos@ua.pt (A.R.); matos@ua.pt (J.N.M.)
2
Department of Electronics Telecommunications and Informatics, University of Aveiro,
Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
* Correspondence: tiago.varum@ua.pt
Abstract:
With the rise of 5G, Internet of Things (IoT), and networks operating in the mmWave
frequencies, a huge growth of connected sensors will be a reality, and high gain antennas will be
desired to compensate for the propagation issues, and with low cost, characteristics inherent to
metallic radiating structures. 3D printing technology is a possible solution in this way, as it can print
an object with high precision at a reduced cost. This paper presents different methods to fabricate
typical metal antennas using 3D printing technology. These techniques were applied as an example
to pyramidal horn antennas designed for a central frequency of 28 GHz. Two techniques were used
to metallize a structure that was printed with polylactic acid (PLA), one with copper tape and other
with a conductive spray-paint. A third method consists of printing an antenna completely using a
conductive filament. All prototypes combine good results with low production cost. The antenna
printed with the conductive filament achieved a better gain than the other structures and showed a
larger bandwidth. The analysis recognizes the vast potential of these 3D-printed structures for IoT
applications, as an alternative to producing conventional commercial antennas.
Keywords: 3D printing; metal antennas; horn antennas; IoT sensors; 5G
1. Introduction
The fifth generation of mobile communications (5G) is driven by an unprecedented
growth in the number of connected devices and shared data [
1
]. With the main goal of being
a unifying connectivity structure for the next decade and beyond [
2
], 5G enables the IoT
reality, where a device will be able to maintain connectivity, regardless of time or location.
Everything will be monitored, measured, or sensed, and to gather that information, the
number of devices interacting with the surroundings will increase exponentially.
New scenarios such as the proliferation of sensors to deliver IoT services associated
to home appliances, health monitoring, smart offices, efficient navigation systems (au-
tonomous cars), immersive multimedia experiences, either through augmented or virtual
reality and cloud computing, will all be combined in a typical 5G network [
1
]. Given the
number of the connected devices, their diversity of nature, sizes, and shapes, the antennas
will face multiple challenges with various forms and the combination of several materials.
New techniques to build antennas need to be investigated, to properly create radiation
structures in the daily objects. Technology must be able to handle heterogeneous and
challenging layouts, always bearing in mind the improvement of both energy and cost
efficiencies along with spectrum performance [3].
Wider bandwidths are probably the most effective method to provide the data de-
mands for 5G services [
4
], thus the migration to the millimeter waves region becomes
mandatory. Several concerns arise with these operation frequencies, essentially due to
the huge path-loss and consequent fragile link result of the occurring diffractions [
1
]. To
overcome these communication issues, combating the large propagation loss in mmWaves,
Sensors 2021, 21, 3321. https://doi.org/10.3390/s21103321 https://www.mdpi.com/journal/sensors
