FEKO's Role in Electromagnetic Protection Design for Civil Aircrafts: A Case Study of COMAC

The Commercial Aircraft Corporation of China, Ltd. (COMAC) was established in 2008 to implement strategy for large aircrafts. The former First Aircraft Design Institute Shanghai Branch of China Aviation Industry Corporation I was restructured and incorporated into COMAC in the same year and was renamed as the Shanghai Aircraft Design and Research Institute of COMAC. The missions of Shanghai Aircraft Design include design, testing, pre-research and key technology research of ARJ21 aircraft and C919 passenger plane, complete independent intellectual property rights of ARJ21 aircraft and large aircraft C919 for which China has completely independent intellectual property rights. The Shanghai Aircraft Design and Research Institute of COMAC has successfully designed the country’s first homegrown large passenger aircraft, covering various areas such as overall pneumatic, strength, structure, integrated avionics, electrical, flight control, hydraulic, environmental control, power, fuel, standard material, airworthiness and information systems.

The Commercial Aircraft Corporation of China, Ltd. (COMAC) was faced with the challenge of designing the country’s first homegrown large passenger aircraft. With the rapid development of science and technology, more airborne radio equipment was being installed in aircrafts, leading to a lot of antennas with a very wide frequency range. However, due to the limited length of the aircraft itself, there was not much space for antenna placement. Antenna pattern distortion caused by the aircraft body and inter-antenna electromagnetic compatibility were the highlighted concerns. During take-off, landing or flight, an aircraft may be irradiated by highpower radio transceiver from ground, air or ships at sea, causing electromagnetic environmental problems. These electromagnetic waves, called high-intensity Radiated Fields (HIRF), can induce electromagnetic fields around airborne equipment or induce high-frequency current on interconnected cables, resulting in function disorder or loss of key/critical equipment, endangering the aircraft’s ability to fly safely and land. Another problem was electromagnetic compatibility (EMC), an interdisciplinary gradually built with the growing complexity of electronic equipments and systems. A comprehensive electromagnetic simulation and analysis tool was urgently needed to eliminate the personnel and equipment hazards caused by electromagnetic radiation fields and to improve the safety and reliability for aircrafts in complex electromagnetic environments.

Shanghai Aircraft Design and Research Institute started to cooperate with FEKO® early in 2004. Using rich and powerful FEKO electromagnetic solvers, various types of high-frequency electromagnetic field problems could be quickly and accurately solved. During the development of multiple aircraft models, FEKO helped to solve many problems related to antenna placement, inter-antenna isolation, high-intensity radiated fields and electromagnetic compatibility. An aircraft is also equipped with a large number of radio equipment, such as airborne navigation, communication and cabin information systems. These systems may be affected by electromagnetic fields radiated by other airborne electrical and electronic equipment during operation. In the design process of commercial aircrafts, the front-door coupling interference of airborne receiver has attracted more and more attention in airworthiness reviews. In engineering applications, interference source equipment is distributed throughout various compartments inside the aircraft, including cockpit, cabin, electrical and electronic equipment bay (E/E bay) and cargo bay. Many airborne antennas are located in the back and the belly of the aircraft. The cabin door gap and window structure also need to be taken into account during modeling and simulation. Both modeling and meshing works can be completed within the FEKO pre-processor module.

• FEKO's solutions have been instrumental in the development of multiple aircraft models, helping to solve many problems related to antenna placement, inter-antenna isolation, high-intensity radiated fields and electromagnetic compatibility. The use of FEKO's electromagnetic solvers has allowed for quick and accurate solutions to various types of high-frequency electromagnetic field problems. This has not only been beneficial during the engineering design phase but also during the flight test phase, providing valuable guidance for troubleshooting. FEKO's solutions have also been widely used in electromagnetic compatibility troubleshooting, saving significant time during flight-test for the electromagnetic compatibility issues arising during the development process. The use of FEKO's solutions has led to improved safety and reliability for aircrafts in complex electromagnetic environments.

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