What is Gallium nitride (GaN) and where can we use it?

Ⅰ. What is Gallium nitride (GaN)?

Gallium nitride (GaN) is an inorganic compound containing gallium and nitrogen with the chemical formula GaN. Since 1990, it has been widely employed in as a direct bandgap semiconductor. The structure of this compound is similar to wurtzite, and it possesses a high hardness. Gallium nitride has a large energy gap of 3.4 electron volts, allowing it to be employed in high-power, high-speed optoelectronic components. Gallium nitride, for example, can be used in violet and non-linear semiconductor-pumped solid-state lasers to produce violet (405nm) laser light (Diode-pumped solid-state laser).

Ⅱ. Military and aerospace applications

Military satellite

GaN is becoming more essential in these systems as manufacturers transition from traveling wave tube amplifier (TWTA) and technology to GaN technology because it is more dependable, has greater power, and is more resilient than previous technologies.

GaN enables the combining of solid-state monolithic microwave (MMICs) to approach power levels previously only possible with as power density improves. For example, Qorvo's Spatium uses patented spatial combining technology to boost power, efficiency, and working frequencies across the spectrum.

Spatium uses a broadband anti-polar fin wire antenna to launch to/from an oversized coaxial waveguide, split into multiple microstrip circuits.

Radar

Satellite networks will increasingly use high-power solid-state broadband technologies like GaN in their radio frequency front-ends (RFFEs). Continuous advancements in GaN performance are assisting in the development of high-power output systems.

Linearity, power, efficiency, reliability, compactness, and weight are just a few of the features that make GaN technology so appealing. In AESE systems, reliability is critical, and GaN can work consistently at greater channel temperatures.

GaN have a high PAE, which implies they use less power, require less cooling, and have lower operating expenses for given output power.

Furthermore, using high-gain, high-PEA GaN MMICs in radar platforms minimizes the total size and cost of the system. This contributes to the new AESA radar system's stricter size, weight, power, and cost (SWaP-C) criteria. In aircraft systems, where weight and size must be decreased, meeting SWaP-C standards is critical.

Electronic warfare

Electronic components with broad power and efficiency, small size, and light weight are required for EW applications. These systems must also be able to function at higher temperatures, with greater dependability, and in exceptionally severe situations. As a result, GaN and technologies are widely deployed, and we continue to see the move from tube-based systems to solid-state GaN and GaAs technologies in the EW arena.

Combining developments in GaN MMIC technology with GaN packaging speeds up the supply of solutions for EW applications that boost bandwidth, compress form factors, improve thermal performance, and enable low-cost plastic packaging. As contractors attempt to produce smaller, broader bandwidth, larger capacity, lower cost, and more powerful EW solutions, GaN is the new technology of choice.

Ⅲ. Commercial applications

5G infrastructure

The growing use of GaN in 5G is due to three key factors: enhanced power output, higher operating frequencies, and lower power consumption. System designers are concentrating on improving amplifier efficiency because PAs spend the most energy in 5G RF FEs. Fortunately, one of GaN's best qualities is its efficiency.

In a variety of infrastructure applications, GaN can boost energy efficiency to new heights. GaN lowers system power usage, saving operators money and making systems more environmentally friendly.

In order for FWA to attain its goal gigabit speeds, it must achieve extremely high output power. The high-efficiency GaN Doherty PA can easily meet the 65 dBm isotropic radiated power (EIRP) criterion, as demonstrated in Figure 1.

Figure. 1 Tradeoffs between Antenna Array Element Count and RF FE Process Technology

Because the waveform shaping gain determines these parameters, GaN has a greater antenna gain and a lower noise figure. When utilizing a uniform rectangular array to produce 65 dBm the PA power output per channel decreases as the number of components increases, as illustrated in Figure 1. Antenna arrays employing GaN technology can deliver the required power output with fewer active elements since GaN has higher power per channel than silicon.

Wired Broadband Applications

When choosing an amplifier, linearity and efficiency are critical factors, which is why GaN is the preferred technology. GaN's excellent efficiency allows for increased linear output power while consuming less DC power. This enables cable designers to achieve faster data speeds and larger bandwidths while also extending the distance between amplifiers and increasing dependability.

Commercial satellite

Commercial satellite communications applications that use GaN and GaAs include 5G backhaul, Ultra HD TV transmission, mobile satellite communications, Internet access for airline passengers, and single-person (portable) terminals.

These trends are driving manufacturers to move away from tube-based systems and toward solid-state devices like GaN. which offer better data throughput and smaller form factors. GaN provides tremendous high-power amplification benefits in commercial satellite communications applications. GaN also supports high-frequency bands such the X, Ku, K, and Ka bands, which are utilized in satellite communications.

Commercial satellite solutions are transitioning away from in the same way as military and aerospace satellite applications are. Solid-state GaN used in MMICs or space-combined products like Qorvo's Spatium. which has instant on capability, needed low voltage rails, reduced noise figure, and improved reliability, is driving this transformation.

GaN is currently a necessary and crucial raw material in the 5G era, and its market growth will continue to increase as GaN technology advances.