A HIRF, or high-intensity radiated field, is a field of RF energy so strong it has a significant impact on the performance of a device under test. HIRF testing focuses on aircraft. In particular, safeguarding against aerospace disasters; HIRF can cause directional malfunctions and potentially aerospace disasters. Common sources of HIRF come from external radiators such as radar and broadcasting, and from transmitters installed on the aircraft.
HIRF regulations exist to prevent aerospace disasters, ensuring aircraft electrical and electronic systems will continue to operate safely without interruption, failure, or malfunction. Specifically, tests are conducted on aircrafts' electrical and electronic systems, which can be damaged or destroyed and cause aircraft to malfunction during flight. A host of regulations govern HIRF testing, including radiated susceptibility requirements mandated by the CRF, FAA, EASA, and numerous other aerospace regulatory agencies. Common testing standards consulted in compensating for HIRF in design include the following.
- RTCA/DO-160 Section 20
- MIL-STD-461G 14
- CFR 23.1308 14
- CFR 25.1317 14
- CFR 27.1317 14
- CFR 29.1317
- AMC 20-158
Required devices for Hirf testing
- Signal Generators
- Begin the process of simulating HIRF by bombarding the device under test with RF emissions.
- Pulse Amplifiers
- Amplify signals produced without changing their waveforms; release powerful pulses of amplification.
- EMC Antennas
- Operators conducting HIRF testing will use EMC antennas to emit the signal generated by the signal generator and amplified by the amplifier.
- RF Power Meters & Sensors
- Measure the output power from the amplifier during HIRF testing, if the output signal is too weak, noise may obscure it, and if the signal is too powerful, distortion or system damage may occur.
- Field Strength Monitors & Probes
- Field probes will measure the strength of a HIRF, giving operators insight into how strong of a HIRF the component under test is currently in contact with.