For the past few years, technology headlines have been dominated by talk of the emerging 5G wireless communication network. And while we are closer towards actually being able to transition and experience the new network for ourselves, there are still a few things that need some work before we can smoothly adjust to the new network.
Just like with any other transition between old and new generation technology, there are some capability issues. One hurdle to overcome involves incorporating, within a single phone, new antennas that can support millimeter wavelengths of signals on 5G networks alongside existing antennas that support the longer wavelengths transmitted by LTE networks. However, this is easier said than done. The main challenge is the placement of the antennas so that both fit inside the mobile device and do not deteriorate each other’s performance.
Seeing as how 5G still has a few years to go before taking over 4G LTE networks, having a device that can harness both 5G and 4G LTE frequencies is desirable to keep consumers equipped with today’s technology, while still ready for the tech of the future. But it is a matter of fitting all the necessary components into a single device that will cause an issue.
Researchers from Aalto University have created a new proof-of-concept study, led by Joni Kurvinen that aims to solve this problem. Many LTE antennas are currently integrated within the metal rim of a phone, which acts as a coupling element, exciting resonating currents throughout the whole device. The design by Kurvinen and his colleagues maintains this approach, with an LTE antenna embedded within the metal rim along one side of the bottom of the phone. In this case, the antenna supports both low and high frequency bands of LTE networks.
The second antenna, which supports millimeter-waves, is designed so that all its metal parts are sufficiently far from the metal parts of the LTE antenna. How far is sufficient? As it turns out, putting it on the opposite side of the phone’s bottom edge is distance enough. The antenna is slipped into a hole drilled into the metal frame, which allows millimeter-wave radiation to pass through.
Stimulations suggest that the dual antenna system yields 60 percent efficiency, which is fairly high for mobile phone systems. But that figure comes with a few limitations. Kurvinen and his colleagues acknowledge that this is a mere prototype phone lacking many other components that appear in commercialized phones. What’s more, the size of the printed circuit board for this prototype is larger than what’s used in typical mobile phones. Lastly, this design supports mm-wave communication coming only to and from the end of the device – whereas, for optimal mm-wave coverage, a handset should also be equipped with antennas producing broadside radiation so signals can be received through the phone’s display and/or back cover.