The Benefits of Combining Lens Technology with the Antenna in 5G RAN
A key to realizing the true potential of the next-generation network
Technical Master in Antenna & Propagation Design, Networks Business at Samsung Electronics
Antenna and lens in 5G
The concept of a lens we are familiar with is the camera lens or telegraph lens. As most of us have learned in high school science class, such lenses help us to clearly view objects in the distance, using reflection of light. Surprisingly, these lenses can be applied to cellular technologies including 5G to enhance the performance of radios. These types of applications have recently emerged as one of the most pursued technologies in the industry.
With the introduction of 5G, mmWave spectrums are available to support large amounts of mobile data traffic for users, in order to deliver immersive mobile experiences. With mmWave spectrum, ‘shadowing’ or ‘fading’ can happen where objects or environmental elements impact the received signal strength of the end user’s device. To mitigate this, advanced radio antenna technology--called Phased Array Antenna--was widely used. The technology had been used for military purposes, and today, is commercially applied to all 5G base stations to enhance performance and increase coverage.
At Samsung, we’ve embarked on a prolonged initiative to enhance this powerful Phased Array Antenna technology, and we have been exploring new possibilities using lens technology. In this blog, we will take a look at how Samsung has taken it to new heights.
Applying Lens to Phased Array Antenna
Lens technology has a unique capability in that it can bend radio signals as it does with light. By applying this concept, we can control beams for various purposes. [figure1]
[Figure 1] Various effects of lens in antenna technology
For example, we can shape the beam to gain higher performance or change the direction of the beam. Moreover, we can even create multiple beams to cover several users. Based on these findings, we started our journey to apply the lens to 5G radio so that we can help mobile operators deliver improved wireless experiences to users. After some extensive trials and research, Samsung developed a prototype lens that can be applied to its 5G solutions, and with this lens technology, 5G performance has improved notably. [Figure 2]
[Figure 2] Improved performance of antenna with lens.
We were excited about these successes but soon realized there was another challenge ahead of us.
Locating the Optimal Focal Distance of the Lens in a 5G radio
Recall that to burn a paper using a lens, you need to hold the lens at a specific height to concentrate light energy from the sun. This specific height is called the focal distance of the lens. Like every lens, to have maximum performance of a lens in 5G radio, it must be implemented at its focal distance. As shown in [Figure 3], locating the optimal focal distance between a lens and an antenna is easy. However, in the case of a Phased Array Antenna, which generates narrow beams from multiple antennas, locating the focal distance is a hard task. Without an optimized technology that minimizes the focal distance, the lens in 5G radio would increase the size of the solution.
[Figure 3] Focal distance comparison
To address this dilemma, Samsung has taken two different R&D paths:
1) Controlling the beam shape, and
2) Reflecting beams emitted from antennas
1) Controlling the beam shape
The first path is to develop a technology that allows multiple number of beams from Phased Array Antenna to be shaped as needed. By changing the shape of beams to be more widely dispersed on the lens, Samsung can shorten the focal distance.
2) Reflecting beams: Using partial reflection
The second approach is using partial reflection. Based on a simple science that any beam can be reflected on certain metal surfaces, Samsung designed a lens with a unique pattern to reflect beams more effectively. Using this concept, Samsung successfully improved the performance of the antenna by 50% even with an extremely short focal distance.
Thus far, we have shown how to obtain higher gain by applying the lens to a 5G radio. However, there are other ways to use lenses in 5G radios.
Lens for Widening antenna angle
Typical Phased Array Antenna in 5G radios have a horizontal steering range of 120 degrees. To cover 360 degrees, three radios are required. However, if the beam steering range of the Phased Array Antenna is widened to 180 degrees, the number of radios can be reduced by 33% - to two radios. Samsung has developed a convex lens to bend the beams and this technology allows 180 degrees of beam steering range for an antenna with minimum performance deterioration. As a result, we verified the feasibility of the lens technology. [Figure 4]
[Figure 4] The benefit of lens for widening antenna angle
We have explored the lens technologies that can be applied to a 5G radio to enhance performance and to increase coverage. Additionally, there are some other next-generation lens technology that we are researching and developing.
Lens with re-configurability
Beam forming, an essential part of 5G technology, is traditionally implemented on the circuit of the antenna. The lenses we have explained so far and the industry has been focused on are “passive lenses”, that have no beam forming feature. Currently, re-configurability of the lenses is being studied and researched by numerous experts at Samsung.
Samsung is now researching and developing the latest lens technology focusing on the following points: 1) simplicity, 2) transparency, 3) re-configurability. The goal of this research is to ensure that the lens could be blended with any antenna through its transparency and broaden the applicability of the lens through re-configuration.
Wireless communication technology is constantly evolving. A new era of connecting everything through wireless networks is right around the corner. Subscribers demand a faster, more reliable network everywhere they go, and to cope with large demand, mobile operators are requiring high performance solutions. To help operators to overcome this, Samsung has been innovating various network technologies including Massive MIMO, Phased Array Antenna, and Lens technologies, enabling operators to build a stable yet reliable 5G network with optimized operating and deployment costs.