In aerospace and defense, some of the biggest areas of innovation and investment aren’t on the battlefield but in the electromagnetic spectrum. From electronic countermeasures to electronic counter-countermeasures (yes, you read that right), techniques for intelligence, surveillance, and reconnaissance systems are evolving quickly.
This means engineers’ jobs are more challenging than ever. System complexity may be increasing but timelines and budgets certainly aren’t. Yet, underlying technologies are stepping up their game with the ability to design more sophisticated systems more quickly.
Four recent innovations will have huge enabling impacts on radar technology over the next several years.
1. Gallium Nitride for Front-End Components
Gallium Nitride (GaN) is considered the biggest semiconductor innovation since silicon.
It can operate at much higher voltages than conventional semiconductor material—and higher voltage means better efficiency. RF power amplifiers and attenuators that use GaN use less power and produce less heat, so there is a huge demand for component suppliers to hit the ground running with GaN chips.
GaN components are particularly in demand for a type of radar that has gained a lot of momentum over the last few years: active electronically scanned array (AESA) radars. These radars consist of hundreds or even thousands of antennas, and steer beams electronically without physically moving the antenna. Because there are so many antenna elements, GaN components will be important for this technology. They enable AESA radars to achieve the same output power more efficiently in a smaller form factor.
From the semiconductor test perspective, component manufacturers are adapting production test for GaN components to better reflect the real-world use cases. For example, you can use vector signal analyzers and generators to create wideband pulses that are more realistic to the real-world environments that these chips will ultimately be deployed in.
2. High-Speed Data Converters for Transmit and Receive
Another exciting advancement is in converter technology. The latest analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) being released by major semiconductor companies are ultrafast!
This is great news for radar, because the wider bandwidth not only allows for better spatial resolution but also makes it possible to implement some pretty interesting techniques. For example, a radar can hop around to different frequencies to avoid detection or use the same sensor to act as both a communications system and a radar simultaneously.
These converters are so fast that it’s actually possible to perform “direct RF sampling,” which simply means sampling so fast that you can acquire RF signals directly without up- or down-converting.
For example, the newest FlexRIO transceiver has 12-bit resolution up to 6.4 GS/s. At these rates, it’s possible to directly sample RF input signals up to C-band by moving much of the signal processing to the digital domain. This is also a big deal for AESA radars, because when you’re dealing with thousands of antennas, you can reduce the size and cost significantly by eliminating mixers and local oscillators.
3. Evolving FPGA Technology for Cognitive Techniques
Unsurprisingly, FPGA technology also continues to improve year after year. The computational capability of today’s FPGAs opens the door for innovative techniques that weren’t possible five years ago.
For example, engineers are now applying machine learning techniques so that radars are more responsive to their environment. By using machine learning, radars can perform new techniques like automatically recognizing different targets, or adjusting their operating frequency or waveform based on what’s going on around them.
In addition, higher level FPGA programming tools like the LabVIEW FPGA Module are becoming more capable, making it easier to port algorithms to FPGAs. This is a game changer for engineers and scientists who don’t have previous hardware description language (HDL) expertise or who have tight timelines. The tight integration between NI hardware and software allows LabVIEW FPGA to go a step further by abstracting the hardware infrastructure, such as PCI Express, memory controllers, and clocking.
4. High-Bandwidth Data Buses for Sensor Fusion
Another key technology that’s paved the way for radar innovation is the evolution toward higher bandwidth data buses such as PCI Express Gen 3 and Xilinx Aurora. Using these buses allows you to aggregate data from multiple sensors for centralized processing.
In the same way that autonomous vehicles use sensor fusion to aggregate data from sensors like radar and lidar, you can use sensor fusion for fighters such as the F-35. Combining the data from radars, electronic countermeasure devices, communications devices, and other sensors ultimately provides pilots better situational awareness.
With the rapid evolution of these underlying technologies, it’s unsurprising that radar techniques and architectures are also evolving.