HIRF Testing (High Intensity Radiated Fields)

At NTS, our experience encompasses more than 50 years of electromagnetic compatibility testing for clients in the aerospace, aviation and other related industries. We maintain fully equipped electromagnetic interference testing facilities in Illinois, Arizona, California, Massachusetts, Texas and New Jersey. With the combined expertise of our team, it’s easy to identify the regulatory challenges your organization faces, and develop a comprehensive testing program that ensures your challenges are met.

Background Information

Of particular concern to avionics manufacturers, high intensity radiated fields (HIRF) are any combination of electrical and magnetic interference strong enough to potentially impact the performance of a device in close proximity to it. HIRF is divided into three frequency bands, and each can affect airplane electronics in different ways:

  • Low frequency electromagnetic emissions between 10 kHz and 50 MHz — Low frequency HIRF use electrical components like an antenna, inducing currents in the fuselage skin but demonstrating little interior penetration.
  • High frequency electromagnetic emissions between 100 MHz and 18/40 GHz — High frequency HIRF creates strong field penetration into the fuselage.
  • Medium frequency electromagnetic emissions between 30 MHz and 400 MHz — Medium frequency HIRF combine the effects of both LF and HF emissions, producing both antenna-like behavior and fuselage penetration.

HIRF and Electromagnetic Testing

HIRF testing is a form of EMC testing applicable to equipment that is subject to extreme electromagnetic environments and/or mission critical equipment whose failure would be hazardous to human safety.As greater dependence is placed upon an aircraft’s electrical and electronic systems performing functions required for safe flight operations, concern has increased for the protection of these systems. Concern for the protection of electrical and electronic systems in aircraft has increased substantially in recent years due to:

  • Reduction in the electromagnetic shielding afforded by new composite materials.
  • Increased use of electrical and electronic systems to perform flight and landing functions.
  • Increased susceptibility of systems to HIRF due to increased data bus and processor operating speeds, higher density integrated circuits and cards, and greater sensitivities of electronic equipment.
  • Expansion of frequency usage above 1GHz.
  • Increasing severity of HIRF environment because of an increase in the number of RF transmitters.
  • HIRF requirements are applied to ensure that the aircraft electrical and electronic systems are able to continue safe operation without interruption, failure or malfunction.

HIRF Testing at NTS

NTS testing labs are fully equipped to provide HIRF and other electromagnetic interference testing for some of today’s most demanding clients. We are the nation’s largest independent product testing and standards compliance organization, with a long history of meeting the needs of military contractors, avionics manufacturers and more. We can ensure you meet the requirements for any of the variousspecifications which include HIRF certification, such as:

  • FAA HIRF Rule & Advisory Circular 20-158
  • RTCA/DO-160E/F: Category A-L, All CW, SW and Pulse Test levels
  • Boeing Requirements: All CW, SW and Pulse test levels
  • Airbus Requirements: All CW, SW and Pulse test levels

HIRF certification typically involves measuring transfer functions to estimate the potential effects of electromagnetic interference (EMI) on an aircraft. We employ a variety of tools and techniques to produce accurate testing that is fully compliant with all required specifications.

Reverberation Chambers

Our reverberation chambers and state-of-the-art amplifiers achieve greater that DO-160 Category L levels from 200 MHz to 18GHz. Test frequecies as high was 40 GHz are now possible at our Rockford, IL, Boxborough, MA, Fullerton, CA, Plano, TX and Tempe, AZ locations. The chambers large usable test volume allow for testing multiple-LRU systems. With field densities capable of achieving peak fields up to 15,000 V/m, these chambers are also drive stand-adaptable and can be mated to a motor drive for rotating equipment.

Check our our article “NTS Quick Guide to Reverberation Testing” on the NTS blog or learn more about this type of testing on our reverberation testing page.

Contact us today for more information about how we can help you meet your HIRF testing requirements, or to request a quote for your upcoming project.

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