- Buyers Guide
Aerospace & Defense Electronics Supplement
Early Returns: U.S. Export Control Reform Positive
A&D Test & Measurement
Efficient Design and Analysis of Airborne Radomes
As urban centers become congested with heavy mobile data traffic, building new, smaller cells to off load some of that traffic is becoming commonplace in making the network flow transparent to the end user. However, smaller cells create a myriad of issues, such as increased leasing costs, adhering to municipality codes for aesthetically pleasing radios, and overcrowded towers, not to mention power and cost issues. Thus, the drum for quality, capacity, and spectral efficiency beats louder each day.
One element of backhaul that has been taken for granted is the importance of the antenna. Often, this element is overlooked while top line technology is sought after for the microwave radio. The antenna has often been thought of as a component where concessions can be made, and costs can be shaved. Since testing antennas is an expensive endeavor, and not easily done in independent or in-house labs, the importance can be overlooked. It’s especially tempting, when there are several vendors offering “similar” products at extremely low prices. However, as this article discusses, “similar” is not always equivalent to ”the same” in terms of standards or quality. The old adage of “you get what you pay for,” could not be truer with antennas.
Having a quality antenna does three things for the backhaul network:
The Benefits of Sticking with Quality
High quality antennas allow the microwave radio and small cell radio that the customer’s R&D team just spent months researching and testing for the best spectral efficiency, scalability, and capacity, to be used in the way it was promised. By pairing a low grade antenna with a cutting edge network defeats the purpose of the cutting edge network. Since the antenna is the means through which all traffic flows, skimping on the technology at this point, prohibits the rest of the system to operate as efficiently as it was designed. Sure, lower end antennas cost less upfront but they can create an overflow of signals, causing interlink interference and lowering the signal to noise ratio performance. The end result? Lower capacity and higher TCO. With limited spectrum resources, using this resource effectively is a central piece to keeping TCO in check.
Better dB performance also means that smaller antennas can be used or that higher modulation schemes can be enabled. Higher order modulation schemes are in almost every microwave vendor’s radio portfolio as a response to the market’s insatiable appetite for capacity. If a substandard antenna is used with a microwave radio that is designed to allow higher modulations, then, due to inadequacies in the quality of the antenna, the radio will throttle down the modulation to a much lower level, resulting in lower capacity and potential congestion, not to mention wasted money spent on a microwave radio with cutting edge ACM (adaptive code modulation). Additionally, smaller antennas, even by one foot in diameter, can save as much as a $1000 per site per year. Multiply that by all the sites in the network, and the savings becomes tangible.
Higher modulation uses larger channels, however, larger channels mean the risk of inter radio link interference rises. The “delicate” high order modulations require immunity or “protection” from potential interferers. Especially where carrier frequencies are being re-used again and again. Frequency re-use is an important element of optimum spectrum utilization. By minimizing interference with high quality antennas that have low side lobe levels, the industry can efficiently use spectrum in areas with crowded channels. In short, low side lobe antennas allow more higher capacity radio links to be packed into a given geographic area, especially when frequency re-use is necessary.
Since antennas are expensive to test in a lab and testing can be an arduous task, it may be challenging to understand why the backhaul network is not operating as efficiently as promised if a substandard or lower class antenna is inadvertently deployed. However, as several operators have found out, the promise of lower upfront costs are quickly swallowed over the headaches of melding various sources of network equipment together, researching or debugging the cause behind under- performing equipment, and trying to get performance targets and scalability from the network that was pieced together.
State of the Market
The antenna market is made up of many vendors, with the leading antenna vendors being: Commscope’s Andrew Antennas, Radio Frequency Systems, General Dynamics, Arkivator, Radio Waves, Airaya, and Integrated Microwave Technologies (IMT). Several Asian vendors also play in the market, offering value based products that compete mainly on price.
Sky Light Research estimates that the antenna market is roughly $500 million. Obviously, this market is very dependent on microwave and emerging millimeterwave radios. The expected dip in microwave in the coming years will be buoyed somewhat by the ramping of millimeterwave radios.
Although antennas are very price sensitive, antenna manufacturers are innovating on technology to help operators keep TCO in check. Even though this keeps prices from declining, savvy operators are realizing the upfront costs pale in comparison to the long term cost of cutting corners. One example of technically advanced antennas isCommscope’s (Andrew’s) Sentinel family. Commscope recently announced a new ETSI class 4 line of antennas, which promises to save operators time and money in the long run by addressing many of the issues discussed in this article.
Realizing that a chain is only as strong as its weakest link, Commscope, launched this new line of cutting edge, class 4 antennas to help operators maximize the technology that is currently being integrated into microwave radios, such as higher order modulation,advanced packet compression, and Multi-channel LAG with cross polarized frequency support. Although, the Sentinel costs more up front, the long term savings in TCO are expected to outweigh the initial cost.
So just how good is it? The chart below compares two antennas. On the left is a value priced antenna and on the right is the Class 4 Sentinel antenna. The central vertical black line at zero degrees represents the intended (boresight) signal and the colored lines represent the signal overflow (or side lobes) at different frequencies. The point of this comparison is to illustrate how interference proportional to side lobe levels can impact the channel, especially in a congested urban environment. The Sentinel’s side lobe interference is much better, thus allowing more links in a dense urban area by creating a stronger signal to noise ratio which enables more capacity. The take away is that a higher quality antenna will provide key improvements in capacity, opening up the potential for lower operational expenditures going forward.
Commscope isn’t the only one with quality antennas. RFS also has cutting edge antennas that offer similar benefits, as do most of the vendors listed previously.
The moral of the story is to not skimp on components to save extra money when installing a quality network. Make sure that quality is end to end, especially in congested data driven environments. Your shareholders will thank you in the long run.
About Emmy Johnson and Sky Light Research: Emmy is the Founder and Principal Analyst of Sky Light Research, a third-party analyst firm specializing in wireless point to point mobile backhaul technologies such as microwave, sub 6 GHz, and millimeterwave radios. The firm’s popular services include quarterly market share reports and forecasts. Sky Light Research was founded in 2001 and is located in Scottsdale AZ, USA. For more information, please email info@SkyLightResearch.comor call +1.480.563.2251.
Get access to premium content and e-newsletters by registering on the web site. You can also subscribe to Microwave Journal magazine.