Multifunction, high-performance AESA radar leads a transformation of the battlefield sensor network

Story

January 30, 2015

Dr. Douglas J. Carlson

MACOM

Active electronically scanned array (AESA) radar systems built with gallium nitride (GaN)-based radio frequency (RF) power components are helping to elevate the capabilities of the modern networked battlefield.

Multifunction active electronically scanned array (AESA) radar is making significant inroads into the modern networked battlefield. AESA radar is featured in technologies such as the Next Generation Jammer (NGJ) capability – developed by Raytheon and soon to be installed on the U.S. Navy’s EA-18 Growler air fleet – bringing conventional electronic warfare and advanced cyber defense capabilities together via an AESA radar-based platform.

Advanced AESA radar is also coming to U.S. Air Force F-16s by way of Northrop Grumman’s Scalable Agile Beam Radar (SABR) technology; Raytheon’s Advanced Combat Radar (RACR) has also emerged as a similar AESA technology platform, offering the ability to simultaneously detect, identify, and track multiple air and surface targets. Every member of NATO has announced AESA upgrade programs based on these and other platforms.

Next-gen radar for increased situational awareness

This evolution of the modern battlefield is being driven by the need for improved connectivity and situational awareness to ensure mission success in the face of unpredictable and dynamic adversaries. The modern fighting force needs to be equipped with advanced sensor and communication infrastructure designed to operate as a unified, highly versatile mesh network that distributes critical data across ground, sea, and air domains at previously unimaginable speeds and bandwidths.

To enable continuous, high-performance data distribution throughout the modern battlefield, the underlying sensor mesh must operate as a homogenous network, adapt quickly to changing operating conditions, and be highly resilient to ensure that the loss of individual sensor nodes throughout the network doesn’t compromise the integrity or effectiveness of the network itself. Next-generation radar systems are therefore critical to providing situational awareness beyond the single platform of operation to the entire networked battlefield. To meet these complex needs, advanced radar systems are transitioning away from conventional radar architectures that rely on mechanical steering – which are prone to limitations in agility and reliability due to size, weight, and functionality – and turning toward AESA radar systems that offer key performance advantages and multifunction capability.

With AESA technology, the mechanical gimbal is eliminated. Scanning is handled electronically via stationary arrays comprised of hundreds to thousands of transmit and receive elements. This array architecture enables simultaneous functions ranging from radar surveillance and fire control to jamming and advanced data link communications. Based on incoming information from nodes across the network, an AESA radar system can be called upon to aid a battle scenario by providing surveillance, jamming an enemy signal, or targeting and eliminating a threat.

Multifunction AESA versatility also enables dramatic improvements in target tracking. Conventional radar systems are optimized for either ultra-high-speed tracking of immediate threats, or long-range tracking of distant targets, but typically not both. Multirole AESA radar can combine these capabilities to allow for high-precision, multi-target tracking spanning both short- and long-range threats. It is easy to imagine how this advanced tracking capability could be applied in a fighter jet cockpit, enabling pilots to detect and visualize a considerably higher number of approaching enemy aircraft and missiles than they can today.

Power for performance

Accelerating the forward progress toward next-generation multifunction AESA radar that strengthens and expands the battlefield sensor network hinges on the ability to develop and manufacture smaller, lighter, wider-bandwidth, and more energy-efficient RF power components that promote multifunction integration. What is needed in all of these cases is a new approach to power component design and packaging that provides greater overall power performance in a smaller form factor with the greatest possible ease of assembly.

AESA radar system designers can achieve high-power operation with improved efficiency while accelerating time to market by using the newly emerging GaN-based RF power components that can be assembled using highly automated commercial techniques. Improved efficiency and lighter-weight system design also enable AESA systems to be placed onto smaller operational platforms – such as unmanned aerial vehicles (UAVs) – that would otherwise be unable to provide critical sensor data in the battlefield.

These new GaN-driven capabilities are yielding a new generation of agile AESA radar systems optimized to meet the increasingly demanding performance and multifunction flexibility requirements of the modern battlefield. Among the many advantages that GaN offers for multifunction AESA radar systems are high-power operation, improved power efficiency, reduced system size and weight, and wide-bandwidth operation (see Figure 1).

GaN delivers minimally eight times the raw power density of incumbent GaAs technology, while boosting efficiency from mid-40 percent to as high as 70 percent depending on the frequency of operation. At the radar system level, the high-output power enabled by GaN-based RF components ultimately enables increased range surveillance with improved resolution in smaller platforms. This capability ensures that AESA radar systems are better equipped to distinguish real from false targets more accurately and alert the operator of threats more quickly. The ability to emit higher power also enables greater flexibility with regard to shaping the signal pulses without compromising on overall system performance.

Figure 1: The gallium nitride on silicon carbide (GaN on SiC) pulsed power transistor for military and civilian radar pulsed applications offers designers a typical 17 W of peak output power with 63 percent efficiency.

(Click graphic to zoom by 1.9x)

The higher breakdown voltage performance of GaN allows for scaling to higher operational voltages, which leads to improved efficiency in the device and therefore the radar system’s power supply. Higher efficiency reduces system-cooling requirements, which are a significant contributor to weight and power consumption, and enables longer mission operation before refueling in mobile platforms such as UAVs and ground units.

GaN in plastic-packaged RF power components has set a new standard for harnessing high power in small enclosures implementing surface-mount assembly, thereby eliminating many of the size and weight limitations of conventional ceramic-packaged GaN-based offerings. This aspect is particularly important given the accelerating proliferation of UAV-mounted AESA radar systems. For UAVs, any reduction in the size and weight of the underlying components has a direct, positive impact on the aircraft’s flight range and operational versatility.

Moreover, the high voltage thresholds of GaN-based RF power components enable increased wideband impedance matching. This capability enables an AESA radar system to perform multifunctional roles across a broader frequency spectrum with increased operational flexibility.

The need for speed

Time to market is a critical consideration for modern military systems, with multifunction AESA radar systems no exception. Design and manufacturing cycles must be accelerated wherever possible to keep pace with rapidly evolving threats. In the electronic warfare domain, the proliferation of improvised explosive devices (IEDs) in urban battle zones has necessitated ever-faster prototyping, testing, and manufacturing of sophisticated IED-jamming devices that aim to minimize roadside casualties and equipment damage. The five- to 10-year design cycles that currently characterize large radar development programs – targeted at large platforms such as aircraft carriers, other warships, and fighter aircraft – will undoubtedly become increasingly compressed as new threats emerge with increasing frequency and are countered with more agile and flexible platforms such as UAVs.

The clear battlefield advantages enabled by multifunction AESA radar make this technology a prime candidate for intensified attention to design and manufacturing efficiency. GaN-based RF power components that support standard surface-mount technology (SMT) assembly lets developers accelerate time to market by leveraging commercial best practices for high-volume manufacturing, ensuring a host of additional benefits including improved assembly yield, lower component count, and reduced-touch labor. By enabling the use of SMT throughout the manufacturing process, radar system manufacturers can avoid the need for cumbersome cutouts, coining, and flange assembly (see Figure 2).

Figure 2: MACOM’s family of gallium nitride on silicon carbide (GaN on SiC) RF power hybrid amplifiers – optimized for military radar applications – supports standard surface-mount assembly, enabling designers to realize improved assembly yield, lower component count, and reduced-touch labor.

(Click graphic to zoom by 1.9x)

Tight integration at the embedded component level reduces the space required for each RF element and reduces the number of overall components needed to be procured, which naturally helps accelerate lead time. Aggregate reduction in part count also minimizes the risk of performance variation from component to component.

Innovation advantage

Continued innovation in GaN-based RF power components promises to accelerate the trend toward advanced, multifunction AESA radar systems by introducing significant benefits including improved power, efficiency, and operational agility; reduced system size and weight; and shorter time to market. As this technology makes its way into the integrated mesh network of sensors that underpins the modern battlefield, it will enhance the potency and agility of our fighting forces for decades to come.

Dr. Douglas J. Carlson received his Sc.B. in Electronic Material from Brown University in 1983 and his Sc.D. in Electronic Materials from the Massachusetts Institute of Technology in 1989. Dr. Carlson subsequently served on the research staffs of MIT and Bell Laboratory. In 1990, Dr. Carlson joined MACOM in its Advanced Semiconductor Division; his current position is Vice President of Strategy. Readers may contact him at [email protected].

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