By J. Sharpe Smith, Inside Towers Technology Editor
It’s crowded at the top. At the top of cell towers, that is. Wireless carriers are adding additional spectrum bands and 5G technology, which means bigger antennas, more ports and more cabling.
RF connectors are impacted by the constant evolution of wireless at the top of towers. As the towers get denser, ports get closer together and it becomes harder to connect cables. As a result, RF connectors are being redesigned to allow antennas to do more without adding weight and wind load.
“We’ve created or designed a lot of solutions to try and address the tower densification issue,” David Smentek, CommScope Director of Engineering, told Inside Towers. “We’ve designed push-pull RF connectors to allow technicians to make connections without having to get a tool into a tight space.”
CommScope designed the M-LOC (Multi-port Latching Outdoor Connector) Cluster Connector to simplify 5G antenna-radio connections, reduce installation time and help prevent connectivity errors, which are especially critical in 4T4R and 8T8R MIMO configurations. The M-LOC system includes NEX10-compatible four- and five-port cluster connector schemes.
“In our M-LOC product, we’ve taken a number of RF connectors and combined them into a single package, so the technician is able to connect four or five RF signals at a time as opposed to one,” Smentek said. “M-LOC installs with a single push/lock motion that reduces installation time by over 75 percent and uses a keyed feature that ensures accuracy in port mating – saving installation time and cost.”
Another way to get more equipment at the top of a tower is through the compact integration of the RF subsystems, such as massive MIMO configuration. The process of integrating antennas, filters and remote radio units also has a major impact on RF connectors.
This connectivity, which traditionally involved the use of coaxial cable jumpers, now requires a board-to-board (B2B) connector solution capable of simultaneously connecting or mating multiple RF paths in a small (and sometimes inaccessible) area.
“For us, these are some relatively new products and we’ve taken a lot of the technologies that we’re familiar with from our traditional HELIAX connector business, and we’re bringing those into the board-to-board connector space now,” Smentek said. “Board-to-board RF connectors are a lot smaller in size, and due to the fact that they’re concealed in most applications, they don’t need to be weatherproof.”
One of the challenges of designing B2B RF connectors is that as many as 64 may be needed to make the connection between the two circuit boards sandwiched together, which can produce alignment issues. “If the RF connectors were all rigid, you really couldn’t align them, so we had to build some kind of float into these RF connectors to allow them to self-align as you bring them together,” Smentek said.
In order to minimize passive intermodulation (PIM) and maximize return loss performance, CommScope looked to the 4.3-10 connector, which is gaining in popularity because of its small size and PIM performance. “People are moving to the 4.3-10 connector because it is smaller, but the other main reason is when it comes to PIM performance, 4.3-10 connector really knocks PIM out of the park,” Smentek said. “We just took the 4.3-10 interface and scaled it down by two-thirds to a 1.5-3.5 interface.”
There may be room at the top, after all, if the RF connectors fit in.
For more information about CommScope’s HELIAX® Innovative RF Connectors, visit https://www.commscope.com/heliax/heliax-innovative-rf-connectors/.
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