The South China Morning Post reported that the carbon silicon technology developed by Xu Xiangang's team at Shandong University has significantly enhanced the "vision" of the J-20 fighter jet's radar, doubling its detection range. This means that even stealth fighters like the F-35 and F-22, which hide far away, are more easily detected by the J-20. This achievement mainly owes to the carbon silicon semiconductor technology developed by the Shandong University team. This raises a question: What role does carbon silicon play in the radar? Compared with another commonly used material in radars, gallium nitride, what are their respective strengths? In fact, they are quite different.

Carbon silicon belongs to the third generation of "wide bandgap" semiconductor materials (a simple understanding is that it is more resistant to high voltage, high temperature, and has higher efficiency). It plays a core role in the power supply part of the J-20 radar:

Firstly, it increases the power density of the power supply: Electronic switches made of carbon silicon are particularly powerful, with fast switching speed and low loss. Previously, with silicon materials, the switching frequency was about 100,000 times per second, while now using carbon silicon can easily reach 200,000 to 300,000 times per second or even higher. What are the benefits of faster switching? Transformers, inductors and other "bulky" components in the power supply can be made smaller and lighter! Thus, the same size power supply can output greater power (power density is increased). Experiments have shown that the radar power supply prototype made of carbon silicon can achieve an efficiency of 95.2% at a high frequency of 270 kHz, and the power density is more than 1.3 times higher than before.

High-frequency operation is especially important for fighter jet radars, making the radar system smaller and saving space, adapting to the aircraft's high maneuverability. The final effect: the radar can see further (enhanced detection range): It is the carbon silicon that makes the power supply more efficient and more powerful, thereby providing stronger and more stable energy for the radar's "transmitting unit." With sufficient energy, the radar can emit stronger detection signals, which can travel farther. The reflected signals from targets are also stronger, so targets can be detected at a much greater distance (especially stealth aircraft). The report says that the detection distance has doubled, and may even be further, and the core reason is this.

So, what is gallium nitride? It is also a third-generation wide bandgap semiconductor material, and it mainly operates in the signal transmission and reception unit (T/R component) of the radar. Compared with previously used gallium arsenide devices, gallium nitride can work at higher power with less loss. This means that the radar signal is stronger, clearer, and has better interference resistance, allowing the J-20 to detect more accurately and gain an advantage in electronic warfare. Gallium nitride devices themselves have high power density and fast switching. This means that the signal transmission and reception modules can be made smaller and lighter. For space-constrained fighter jets (such as the J-20), more signal transmission and reception units can be placed in the same size radar panel. The more units there are, the more precise the radar can be, and the more targets it can track simultaneously.

Key difference: Gallium nitride mainly works in the "front end" of the radar, responsible for signal transmission and reception. Carbon silicon mainly works in the "back end," responsible for powering the entire system. They are experts in different parts of the radar.

It can be said that the strong combination and perfect cooperation of carbon silicon and gallium nitride are the core technical guarantees for the current J-20 radar's superior performance. With the continuous development of technology, especially the maturation of new materials such as Ga₂O₃, the "sharp eyes" of future fighter jets will surely see further and more clearly!



Original article: https://www.toutiao.com/article/7523140099048063534/

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