RF & microwave innovation enables military 5G solutions

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October 17, 2022

The U.S. Department of Defense (DoD) – not so much as the driver but rather the consumer of commercial technology –often lags behind the commercial world when it comes to adapting wireless technology like 5G and LTE technology. The commercial world is already leveraging 5G solutions en masse: Just look at the screen of any cellphone.

The slower adaption always loses ground, not just to the glacial DoD acquisition process but also to the security requirements for military-communications systems and ensuring the new tech is interoperable with existing warfighter systems.

Defense companies and commercial wireless companies are working together to demonstrate the capabilities of 5G for military programs, including Joint All Domain Command and Control (JADC2). Improved connectivity not only improves communications but also speeds the collection of critical data for intelligence, surveillance, and reconnaissance (ISR) missions and electronic warfare (EW) applications.

“The DoD began facilitating adoption of 5G technology in 2020,” says Bob Vampola, vice president of the aerospace and defense business unit of Microchip Technology (Chandler, Arizona). “Funding has been provided to demonstrate 5G applications and technologies at various military facilities and for key applications. Funding is intended to promote technology development, mitigate vulnerabilities, influence standards, and engage industry partners.”

The DoD needs 5G for the same reason as commercial users: increased bandwidth and enhanced connectivity.

“What’s going on in [commercial] 5G absolutely is a parallel to what’s going on in the military,” says Bryan Goldstein, vice president, Aerospace and Defense, Analog Devices (Wilmington, Massachusetts) in a podcast titled “Semiconductor supply chain, radar & electronic warfare designs, engineering talent” (readers can listen to this podcast at https://militaryembedded.com/radar-ew/rf-and-microwave/semiconductor-supply-chain-radar-electronic-warfare-designs-engineering-talent). “The military realized they don’t always need their own systems, but maybe if they could use the communications protocol and then find ways around encryption and being able to protect data in different way, they could ride onboard with commercial 5G and in parallel LEO [low-Earth-orbit] satellite constellations. [While] we’re just starting to get into this with our [military] customers, they believe this pipeline and this communications protocol will work for them in some applications.”

For some applications this means diving “all the way into the architecture of semiconductor transceivers and communications protocol, but [for others] it is as simple as [managing the] encryption methodologies at both ends of their communications chain," he adds.

“5G technology offers fundamental capabilities critical to multidomain operations captured by the military like low latency and wide bandwidth systems, as well as flexible incorporation of diverse systems to bring different sensors and communications channel together effectively,” just as 5G does in the commercial world with autonomous automobiles and remote healthcare, Goldstein notes.

While commercial 5G systems are becoming abundant, deployment for military 5G systems will be slow as the investment in building blocks for 5G systems has only just begun.

“There is still a long way to go,” says Brian Murphy, business development executive with Benchmark Electronics (Tempe, Arizona). “We are mostly seeing development of the building blocks, like customers looking for custom filters. Filters are really a bellwether that normally comes early in a technology’s development, so that speaks to how early 5G for the battlefield still is. A lot of progress has been made on evaluating vulnerabilities and security and developing solutions to mitigate those challenges. That is an essential step, but still shows that true implementation is several years out.”

Supply-chain issues are also impacting 5G development. “We have been serving commercial 5G customers for some time,” says Hiep Truong, manufacturing design engineer with Benchmark Secure Technology. “While keeping defense designs similar to commercial products has value from a simplicity/replaceability perspective, defense customers have greater supply-chain requirements, particularly for country of origin. While commercial 5G network infrastructure providers are looking to diversify supply chains away from China, for battlefield 5G this is even more of an imperative. People are looking for things like filters made in North America without adding so many specifications and requirements that they are no longer close to being ­commercial products.”

Demanding commercial-level performance

In the same way as commercial users of 5G, military users will need increased bandwidth, more power density, increased coverage, and the like. Enabling these demands starts at the component level.

“ADI [is] starting to get interest from [military] customers talking about our work in about 5G” including RF and microwave solutions such as transceiver solutions, power, and software solutions, Goldstein says. “Military customers are very interested in [5G] work at the hardware and software system level,” he adds.

“We are seeing more and more adoption of higher-power-density GaN [gallium nitride] on SiC [silicon carbide] HEMTs [high electron mobility transistors] and MMICs [monolithic microwave integrated circuits] in the military and aerospace sector in the Ku band, Ka band, L, S, and C bands for radar, electronic warfare, aviation, and satellite communication applications,” Vampola says. The trend is being driven with the need for higher-output powers for these applications to drive longer distances, as well as new applications such as LEO satellite communication for broadband internet access. The ICP2840, Microchip’s flagship product for 5G and satellite communication, has output power of 10 W with power-added efficiency (PAE) of 22% and gain of 22 dB, he adds. (Figure 1.)

[Figure 1 | Microchip figure ]

Meeting military requirements

Battlefield environments, unlike many commercial applications, are often extreme settings, so the 5G systems and the RF and microwave components deployed to these areas need to be rugged, resistant to extreme temperature changes, and resistant or tolerant to radiation.

“Military systems need to operate flawlessly in harsh environments,” Vampola says. “It will be important that these 5G applications use components that are robust enough to handle these environments. This will require selecting components from the industry that offer better reliability over extreme temperatures, humidity, and even adverse radiation environments. In addition, military systems will require working only with component suppliers who can implement physical/operational security measures, while also offering detailed supply-chain risk-management processes with proven commitment to military applications by supporting longevity of supply.”

These ruggedization and security measures must also be applied in ever-shrinking design footprints as the military continues to issue reduced size, weight, and power (SWaP) requirements in every application.

“We are seeing demand for reduced [SWaP] as well as cost on all RF/microwave components and systems for 5G and other high-frequency communications applications,” Benchmark’s Truong says. “One way technology developers are approaching this challenge is by combining RF/microwave/mmWave and digital functions once on separate PCBs [printed circuit boards] or even separate modules into single PCB assemblies or modules using advanced circuit materials. In terms of filters, Benchmark is offering several customizable SWaP-enabling design families, some with responses to 40 GHz, which leverage stripline designs fabricated on low-loss circuit materials for outstanding performance in compact, lightweight packages to fit SWaP needs.”

For such applications Benchmark developed an LPI/LPD [low probability of intercept/low probability of detection] UWB [ultra wideband] radio module that can be used for secure last-mile communications as part of a broader battlefield network. UWB communications is considered a valuable, complementary technology to 5G that can operate effectively within 5G networks, Truong says. “UWB technology enables secure, reliable wireless connection of soldier-worn sensors and other tactical electronics and for last-mile radio connections, such as for wireless robotics controllers, in situations where detection of the signal would put soldiers at risk.” (Figure 2.)

[Figure 2 | The LPI/LPD UWB radio module from Benchmark Secure Technology can be used for secure last-mile communications as part of a broader battlefield network.]

Challenge: interoperability

Enabling interoperability within military systems has been a decades-long challenge for defense electronics designers.

“Across the Joint Domain battlespace, there are so many legacy systems using so many protocols and connectivity methods,” Murphy says. “Those are not all going to be replaced overnight. And battlefield 5G represents network communications in place of traditional radio-to-radio communications. For this reason, battlefield 5G is likely to be made up of layers including not just mmWave communications between cellular connectivity points, but also satellite backhaul, LPI/LPD UWB, and other connectivity options. Since any implementation will need to take place in phases, setting the standards for interoperability will be foundational to the success of the system.”

To solve the interoperability issue over the long term, DoD leaders are also requiring new programs and upgrades to take a modular open systems approach (MOSA). This requirement applies to communications systems as well.

“5G is one of the technologies that will contribute to high-speed, low-latency data transmissions that enable artificial intelligence (AI), battlespace visualization, and other advanced computing applications in the defense space,” Truong says. “We’re particularly paying attention to Project Convergence, as one example, where the U. S. Army has announced it will be demonstrating Vertex’s Gateway Mission Router 1000, vehicle-borne hardware with a MOSA approach to translate otherwise incompatible formats and securely transmit data. Since replacing every proprietary and otherwise existing standard is not going to happen overnight, simple yet powerful MOSA systems like this are going to be key.”