Silicon has defined the performance envelope of defense electronics for decades, but many modern systems now operate at voltages, temperatures and switching frequencies that approach the physical limits of silicon MOSFETs and RF devices. Gallium nitride (GaN), a III-V wide bandgap semiconductor, has emerged as a practical solution for these constraints. Its material characteristics directly address the power density, thermal efficiency and frequency requirements that shape contemporary radar, power conversion and spaceborne electronics.

GaN’s primary advantage originates in its wide bandgap, approximately 3.4 eV compared to silicon’s 1.1 eV. A larger bandgap increases the critical electric field at which breakdown occurs, enabling devices to sustain higher voltages in smaller geometries. This also reduces leakage current at elevated temperatures, which supports stable operation under high thermal loading. Combined with a high saturation electron velocity and strong electron mobility, GaN devices can switch at significantly higher frequencies with lower switching losses than silicon MOSFETs or LDMOS devices.

From a device-physics perspective, these parameters translate into higher current density, lower conduction loss and improved efficiency at both low and high duty cycles. For RF applications, GaN-on-SiC structures leverage the high thermal conductivity of SiC substrates to dissipate heat from high-power, high-frequency operation. For power electronics, GaN-on-Si devices allow compact, high-voltage switching stages suitable for converters, actuators and power conditioning units used throughout air, ground and space systems.

Across the defense sector, GaN has already become a core enabling technology in systems with demanding electrical and thermal requirements. In radar, Raytheon has deployed GaN-based transmit-receive modules in multiple active electronically scanned arrays, allowing higher effective radiated power, extended range and improved thermal stability in long-duty-cycle operation. Northrop Grumman, Lockheed Martin and others have incorporated GaN into wide-area surveillance radars, shipboard SPY-class architectures and next-generation fighter apertures. In electronic warfare, GaN power amplifiers support high-power, broadband jamming and rapid tunability across contested RF environments. In power conversion, companies developing electric military vehicles and high-efficiency airborne power systems are adopting GaN converters to reduce system mass and thermal load. In space systems, manufacturers of satellite buses and deep-space payloads are integrating radiation-tolerant GaN power stages to improve efficiency and reduce the size of thermal management subsystems.

Radar performance provides one of the clearest illustrations of the material’s advantages. AESA systems benefit directly from GaN’s higher power density and thermal stability. GaN devices support higher duty cycles without degradation, which enables extended range and improved discrimination in long-range tracking and fire-control radars. These improvements are not dependent on architectural changes; they arise directly from the device physics of GaN compared with silicon-based RF technologies.

In power electronics, GaN’s fast-switching capability enables converters operating at frequencies an order of magnitude higher than silicon designs. Higher operating frequency reduces the required size of inductors and capacitors, improves transient response and increases system efficiency. These characteristics are valuable in electric military vehicles, directed energy systems, distributed power architectures and compact airborne or spaceborne power supplies. GaN’s thermal behavior also reduces the size and weight of heatsinks and cooling systems, which supports system-level reductions in SWaP.

GaN has demonstrated particular value in radiation-exposed environments. Wide bandgap semiconductors inherently offer strong tolerance to total ionizing dose, and GaN devices exhibit stable gate leakage, threshold voltage and on-resistance under radiation conditions typical of space missions. Radiation-hardened GaN power devices that maintain electrical stability after exposure to both ionizing and single-event effects are now available for high-reliability spaceflight applications, enabling reductions in thermal mass and simplifying thermal design.

As GaN adoption expands, system-level engineering considerations have become central. Fast switching introduces sensitivity to parasitic inductance and layout-related failures. Effective packaging must manage thermal paths, minimize loop inductance and address high-frequency electromagnetic interference. Board-level reliability factors such as solder fatigue under thermal cycling and the behavior of substrates at elevated temperatures require careful analysis. These engineering challenges are increasingly reflected in qualification flows and reliability standards developed across the mil-aero supply chain.

Ongoing research indicates that GaN technology will continue to evolve into higher-voltage and more integrated configurations. Vertical GaN structures, which conduct current perpendicular to the wafer surface, are expected to support multi-kilovolt operation and may extend GaN into heavy power stages now dominated by silicon carbide. Monolithic GaN integration is advancing toward combining gate drivers, protection circuits and logic functions on a single chip to reduce parasitics and simplify converter design. Parallel developments in RF and power GaN may eventually support multifunction apertures that combine radar, communication and electronic warfare capabilities.

GaN has transitioned from a specialized RF technology to a broadly applicable semiconductor platform for defense electronics. Its bandgap, breakdown field and mobility characteristics provide functional headroom that silicon cannot match, particularly at high voltage, high frequency and high temperature. As reliability standards mature and manufacturing capacity expands, GaN is poised to become an increasingly standard design choice across radar, power systems and high-reliability space hardware.