Military Embedded Systems

GaN in space, military RF trends


June 15, 2021

John McHale

Editorial Director

Military Embedded Systems

GaN in space, military RF trends
Dean White, Qorvo

Satellites, spacecraft, and communications systems are leveraging the performance benefits of gallium nitride (GaN) RF components as demonstrated by the successful landing of the Mars Perseverance Rover. GaN also fuels innovation in military electronic warfare and radar systems. Dean White, senior director of Defense and Aerospace for Qorvo, discussed these trends with me in the following Q&A. We also covered the COVID-19 pandemic’s impact on the U.S. semiconductor industry, military funding, and the engineering recruitment in the defense industry. Edited excerpts follow.

MIL-EMBEDDED: Please provide a brief description of your responsibility within Qorvo and your group’s role within the company.

WHITE: I have [profit and loss] responsibility for Qorvo’s Defense & Aerospace (D&A) business and provide guidance for its strategic direction based on market needs, technology trends, and customer feedback. The Defense and Aerospace division [plays] a vital role for the entire company in terms of developing new and innovative products and manufacturing processes that push the limits of form, fit, function, performance, and cost. These breakthroughs are routinely shared across business units to benefit the entire company. [We] combine gallium nitride (GaN) and gallium arsenide (GaAs) in a single multi-chip module (MCM), making it perfect for defense applications that require reduction in size, weight, and power (SWaP). A key example of this is evidenced by the recent awarding of the Navy SHIP RF (state-of-the-art heterogeneous integrated packaging) contract to Qorvo.

Qorvo made news with the landing of the Mars Perseverance Rover, as GaN and other components are used in the rover systems. What are the unique requirements for RF components leveraged in space applications?

First and foremost, quality and reliability are at the top of the list for space applications since you only get one chance to get it right. Running a very close second is performance. It’s not good enough to just survive in space, you need to be able to deliver on performance as well. With today’s increasing number of satellites and orbital communications networks it is vital to maintain signal strength and integrity to ensure reliable high-performance communications. Qorvo has been in the space business for over 25 years, so we understand that where you operate in space makes a big difference on the type of screening required for space-bound products.

How do you manage the radiation-hardening of your ICs?

The level of radiation screening is determined by the customer requirements and the intended space application. Qorvo does not specifically “manage” the radiation-hardening of the GaAs and GaN products. We have radiation data on select products as well as third-party data on select products from different GaAs and GaN processes that give us confidence that the parts are rad-hard to a given level. CMOS products are designed specifically for rad-hard levels depending on application and orbit.

GaN continues to be the hottest tech in the industry. Does GaN technology have any unique properties that enable performance in space systems? Which defense applications are leveraging GaN the most and why?

We have traditionally used GaAs for space-based devices, but we see a growing demand and need for GaN in space. There is growing interest from our customers to use GaN devices in their applications because it offers higher power density and higher operating voltages that can have a positive impact on SWaP-C [size, weight, power, and cost] for the overall system. GaN power amplifiers are also being used in space applications in place of traveling wave tubes (TWTs) because they have higher reliability. Defense radar, electronic warfare (EW), and com­munications system OEMs are rapidly adopting GaN technology in their next-generation designs. With recent improvements in output power, efficiencies, and bandwidth, GaN power amplifiers are at the center of the radar, EW, and communi­cations revolution. Qorvo recently released a 2-20 GHz GaN power amplifier with > 20 W of saturated output power. But the technology breakthrough we are most excited about is the recently released electronically reconfigurable dual-band (S-X bands) PA (QPA0007). This new technology will revolutionize how radar and EW systems are designed in the future.

How do GaN and LDMOS [laterally diffused metal-oxide semiconductor] compare?

The choice between GaN and LDMOS depends strongly on the application need and the program’s priorities. Performance, development cost, and fielded operational cost of the system must be considered. GaN has significantly higher power density than LDMOS, which reduces parasitic capacitance, allowing for higher fractional bandwidths and increased efficiency. At S-band and above, GaN is the primary solution due to operation frequency, power density, higher efficiency, and module size. At frequencies below 2.5 GHz, the delta in efficiency between LDMOS and GaN is lower than that above 2.5 GHz, but GaN can support larger fractional bandwidth applications, has higher efficiency, and with high reliability has been shown to have lower fielded operational cost versus LDMOS. In the past LDMOS has had a much lower development cost for material, but as time passes the gap between GaN and LDMOS is narrowing quickly.

RF and microwave technology fuel much of the radar technology development in the military market, but the automotive radar market promises even larger growth. How is innovation in automotive radar driving military RF and microwave designs?

All radar is not created equal. It is true that much of radar development in the past has been funded by the defense industry. Radars for defense and automotive applications are very different, even though the intended result is similar. Defense-based radars generally operate at much higher RF power and across a wide spectrum of frequencies depending on the application, while automotive-based radar operates at lower RF power and over a relatively narrow band of frequencies. Defense radar systems are generally very large, heavy, and expensive, whereas automotive systems need to be small, lightweight, and inexpensive. As you can see, these two models are diametrically opposed. However, what we see happening today is these two models beginning to slowly converge to where defense systems are getting smaller and lighter and automotive systems are getting smarter and more capable. Due to economic and competitive pressures, automakers have had to do some innovative things to put radar technology in cars and I think the Department of Defense (DoD) and primes are taking a hard look at how they can reduce the size and weight of their own systems based on these innovations. In the defense industry it is all about SWaP reduction and the auto industry is already doing that effectively.

Has the pandemic impacted the semiconductor market in the U.S.? Do you see more requirements for “made in the U.S.” due to supply-chain concerns?

Yes, it is safe to say the pandemic has affected virtually every aspect of our lives and the semiconductor market is not immune. At the beginning of the pandemic last year, there was a lot of uncertainty and Qorvo – like most other semiconductor manufacturers – faced tremendous uncertainty as to what the demand curve would look like. We contemplated that demand for our customer’s products would be reduced as people lost employment and began to work from home. In fact, the opposite occurred, and demand for our customers’ products grew, thus our products saw an increase. Working from home drove increased demand globally. To support this increased demand, Qorvo quickly and proactively established very strict processes and protocols to protect our employees and to keep our factories running. Because of this, we were able to optimize our output to take advantage of the increased demand and to grow our business during the pandemic. I think the best way to sum up our manufacturing success is that we were able to bend without breaking.

Qorvo is a direct benefactor of the U.S government’s renewed effort to bring key semiconductor manufacturing capability to the United States. Qorvo was recently awarded the RF SHIP program by the DoD. This is the first step at re-establishing the U.S. as the semiconductor innovation and manufacturing leader. As more and more manufacturing has moved oversees, it has slowly eroded our ability to sustain a domestic supply of critical semiconductors for defense applications. We have become dependent and reliant on other nations to provide us with the products that help protect our nation.

Funding for space, radar, and electronic warfare has been rising the last few years. Do you see that continuing post-pandemic and under a different administration?

As with any new U.S. administration, you just don’t know what to expect, but these decisions are typically influenced by world events; the fact that competing nations continue to invest heavily in new technologies represents a real potential threat to our national security. In my opinion, for the U.S. to maintain a battle-ready deterrent, the country needs to stay vigilant and continue to invest in new technologies that will provide us with an advantage. Based on this, I see spending for these defense programs and others to continue at present levels for the foreseeable future.

When one attends a trade show (pre-pandemic, of course) – such as the International Microwave Symposium (IMS) – one can’t help but notice there is a lot less gray hair at these events than at the large Army and Navy events. Does the military-electronics industry have a recruitment challenge on its hands?

You make an interesting observation. As in any industry, you expect a certain amount of turnover each year. However, the defense industry is unique in that once you are in, you usually stay to the end of your career. For the past several decades, the defense industry has been able to insulate itself from this high turnover rate by pulling from its deep talent pool. Unfortunately, time does march on and the defense industry is now faced with an older-than-average workforce that presents a new challenge as far as recruiting new talent. I think we have come to an inflection point where it is important for employers to offer prospective employees the flexibility to explore new opportunities within the company and leverage their past learnings to help enhance their new roles. If possible, companies could enable these employees to cross over between defense and commercial product design.

Looking forward, what disruptive technology or innovation will be a game-changer in the space and military RF/microwave world and and why? Predict the future.

Simply stated, “continued integration” offers industry the greatest benefit for the future. Meaning that with further integration, we can design smaller systems with greater capability like unmanned vehicle technology and space-based capabilities that we were unable to achieve before. This would allow us to perform several different missions with a single platform, as opposed to having multiple platforms. This level of “platform standardization” would offer lasting and meaningful changes in every branch of the defense industry from supply-chain logistics to battlefield readiness and operation. It would also allow the DoD to free up valuable resources to fund research that is vital to national security.

Qorvo •

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