Other than waveguide, connectors and cable assemblies are probably the most mature category of RF, microwave and mmWave components. Yet connectors and cable assemblies do evolve, driven by performance requirements for higher frequency and higher power operation, low passive intermodulation (PIM) distortion, rugged environments and shrinking system size.
For this issue of Microwave Journal’s longstanding Cables & Connectors (C&C) supplement, we thought readers would find a survey of manufacturers informative, to see how markets are shaping these RF interconnects and how the industry fared during the pandemic. We invited 17 companies in Europe and the U.S. to respond to our questions; 10 did so: CAES, Gore, HASCO, Maury Microwave, Mini-Circuits, Molex, Pasternack, Samtec, Southwest Microwave and SPINNER.
Our questions and company answers follow. We’ve edited and consolidated some of the responses to keep the article concise and summarize common themes.
HOW HAS DEMAND FARED DURING THE PANDEMIC?
While some markets suffered from lower demand because of the pandemic, most respondents reported either a temporary decline or overall growth in business.
Illustrating this, CAES saw demand from test and measurement (T&M) slow, attributed to less lab work as engineering teams began working from home during the early months of the pandemic. However, aerospace and defense cable assembly revenue grew 5 to 7 percent over the past two years, reflecting demand from aircraft and land-based ELINT and SIGINT systems.
Similarly, Maury Microwave reported the pandemic impacted customers differently, largely reflecting country and company policies. “Many companies reduced access to their labs, which in turn lowered the need to replace cable assemblies. Others went full-speed ahead and doubled or tripled their annual purchases as programs came online or new manufacturing sites opened.” Overall, Maury’s cable assembly business grew.
Echoing the same theme, Molex saw demand from the telecom and broadband segments increase, reflecting the abrupt shift to working from home and remote schooling. Automotive demand dipped during the second quarter of 2020, then ramped up the following quarter and has remained strong. Molex said it “shipped more coax cable assemblies at the end of 2020 and throughout 2021 than ever before,” with 2022 demand from equipment manufacturers and harness tiers remaining “extremely strong.”
Gore, HASCO, Pasternack and Samtec reported steady demand during the pandemic. Samtec has seen a strong reception for its new mmWave cable assemblies, which reach 50 and 67 GHz. SPINNER said it saw no effect on demand from the pandemic; its sales grew some 20 percent in 2020.
HAVE YOU BEEN AFFECTED BY SUPPLIER LEAD TIMES OR SHORTAGES?
While the pandemic didn’t hurt demand, did it hurt the supply chain for connectors and cable assemblies? Yes. Most of the companies did see shortages or increased lead times on materials and were managing their supply chains to minimize disruptions to customers.
The exceptions: Southwest Microwave said it did not experience extended lead times or supply shortages, perhaps because of its manufacturing model and customer demand declined. Pasternack said it was not adversely affected because of its “availability model where we always have stock available for same-day shipping,” including finished assemblies and components to build assemblies. Similarly, Mini-Circuits said its operating model of stocking inventory helped it avoid supply chain delays hurting customers. “In our experience, interconnect products are often spur of the moment purchases. Customers get into the lab and realize they’re missing the right cable or adapter for their test set-up, and they need it fast, so we’ve always maintained stock and availability of these parts to be prepared for those situations.” Maury Microwave said its inventory strategy enabled it to offer “thousands of cable assemblies and tens of thousands of adapters from inventory or with short lead times.”
As Samtec is vertically integrated, internally manufacturing its cable and many components, it has more control than many companies. While it experienced some lead time issues with external suppliers, they were not “major disruptors to our ability to service our customers.” For Molex, its long-term supply agreements “have worked in our favor,” although lead times on some resins increased, causing shortages and additional logistics costs. While some suppliers claimed force majeure, Molex avoided passing those on to its customers.
CAES said global shutdowns increased lead times for raw materials, delaying deliveries by one to two months and, for some specialty products, three to four months. SPINNER said it had difficulties with some suppliers, especially those in Asia. HASCO also said lead times for raw materials “have increased substantially over the past 18 months.” Reframing the challenge to a positive outcome, HASCO said it “created new opportunities to develop new supplier relationships and introduce alternate product lines” to support customers.
For several years, the hottest market has been 5G, adding bands to the sub-6 GHz spectrum and commercializing mmWave frequencies for mobile phones. We wondered how this has shaped RF/microwave cable assembly development. With many of the new 5G bands below 6 GHz, a spectrum well covered by RF/microwave components, the connector and cable assembly suppliers were already well positioned, as confirmed by our respondents. Yet sub-6 GHz 5G poses new challenges.
To achieve the higher data rates promised by 5G, base stations are adopting massive MIMO (mMIMO) architectures that multiply the number of transmit and receive channels compared to LTE MIMO base stations. This increase in channels leads to more volume for cable assemblies and connectors; however, operator demands to minimize the size and weight of base stations means smaller, multi-port interconnect systems, with lighter and smaller cable assemblies needed to fit in tight spaces. The connector interfaces must be able to handle many connect/disconnect cycles without degrading electrical performance.
Gore and Molex both cite the importance of the cable assembly in minimizing electromagnetic interference (EMI). Gore notes that 5G operates in bands very close to those used by aircraft survivability equipment, navigation and communication systems. Spectrum congestion can create interference with systems critical for the safe operation of aircraft—witness the concern over 5G use at C-Band and possible interference with aircraft altimeters. “It is even more crucial for airframe microwave/RF cable assemblies to be properly shielded from EMI. Maintaining signal integrity in these challenging environments is critical for the reliability of the aircraft’s electronic systems,” says Gore.