Phased array antennas, traditionally used in aeronautics, defense and satellite communications settings, transmit a signal to a series of coordinated antennas which work together to increase signal strength in a particular direction. Now, the technology is being adapted to meet the needs of service providers looking to leverage high-capacity millimeter wave frequencies for 5G systems.
Ian Gresham is a distinguished fellow of technology at integrated circuit firm Anokiwave, which produces highly integrated silicon core IC solutions and silicon front end for millimeter wave applications, as well as partners with Ball Aerospace on the production of phased array antennas. Gresham said that, compared to mobile, delivering fixed wireless over millimeter wave frequencies “is a relatively static problem. My base station is fixed, it’s at the top of a pole; I just have to send data to these 14 houses. The first point is from a practical point of view. The second point of view is coming from a business case point of view. I think the infrastructure roll out for mobile connectivity is going to be a lot more complex. But, from a Verizon or AT&T perspective, one the main costs is the process of laying cable and feeding fixed infrastructure to all the houses. If you can do that wirelessly and increase the customer base, that can save them a lot of money.”
Anokiwave is at the forefront of this antenna evolution. Gresham explained, noting the company has decades of experience working in A&D and satcom, but, in that type of application, he said a single piece of equipments cost a few million dollars, which limits the potential market. “There was this pent up demand, so if we can drive the cost out of them and make them order of magnitude cheaper, there’s this new market and set of applications we can open up.”
Gresham said initial interest was in the 60 GHz WiGig space. “Our thought process was, if we can make phased arrays for commercial and consumer products at 60 GHz, then it’s applicable also for 5G. That was our initial starting point. What has been surprising to us is how fast the market has accelerated and how quickly demand has accelerated. We started developing products for 5G about 18 months ago. We knew the 5G bands were likely going to be somewhere in the 20 GHz to 40 GHz space. We took some of our satcom products at 30 GHz and took our best guess at what the likely architecture would be for a TDD 5G system and converged them at 28 GHz. It was an educated guess and a gamble, but we’ve had an extremely strong pull from the marketplace for those products.” Anokiwave has also recently released products for the 39 GHz band, which along with 28 GHz is of major interest to AT&T and Verizon.
Anokiwave partners with Ball Aerospace to put its IC technology into planar phased array antennas. Gresham said the company’s long history with millimeter wave technology, coupled with their product portfolio, is meant to provide operators with a “reference design” that can be used to develop a field product. “Our value proposition as a company is we don’t just sell you the IC. We’ll work with you to understand your system problems and tailor the IP and the system architecture. Phased arrays are a completely new technology for operators, and the higher the frequency you go, the more problems you have. We wanted to give them a helping hand up the ladder by putting our hands on the table and saying this is not intended to be your end solution or a field deployable thing, but it’ll help you figure out what all those problems you need to figure out are.
Earlier this year National Instruments used Anokiwave’s 28 GHz phase array antenna to demonstrate a real-time, over-the-air prototype system aligned with Verizon’s 5G Technology Forum specification. That test system, showcased at the IEEE Wireless Communications and Networking Conference in San Francisco, used OFDM with eight component carriers in a 2×2 downlink MU-MIMO configuration resulting in a 5 Gbps throughput, scalable to 20 Gbps with eight MIMO streams, according to National Instruments.