High Intensity Radiated Field (HIRF) Testing

With the complexity of your product ever increasing, and the use of composite materials we have invested heavily to match our EMI/EMC test services to the increasingly demanding levels required.

As a result our capabilities can accommodate even the highest HIRF testing levels required by commercial, military and aircraft manufacturer standards.  With Engaged Experts actively involved in RTCA Special Committee 135, and the SAE AE4 HIRF/EUROCAE WG-14 Joint Working Group, we are committed to staying on the leading edge of the industry and helping you understand the technical requirements.

Element can perform HIRF testing at test levels that fully meet and exceed the following requirements:

• FAA HIRF Rule and AC 20-158, ALL CW, SW, and Pulse test levels, for ALL Environments
• RTCA/DO-160D/E/F/G, ALL CW, SW, and Pulse test levels, for all Categories, including Cat. L
• Boeing D6-16050-4/-5/-6, ALL CW, SW, and Pulse test levels
• Airbus ABD0100.1.2, Rev E/F/G, ALL CW, SW, and Pulse test levels
• MIL-STD-464A/C, ALL CW, SW, and Pulse test levels
• ADS-37A-PRF, Table I, Part A & B, ALL CW, SW, AM, FM, and Pulse test levels
• Def-Stan 59-41 & 59-411 DRS02.B, ALL Air, Sea and Land CW, SW, AM and Pulse Levels

HIRF Testing Facilities 

Our high intensity radiated field (HIRF) facilities include a suite of specialist antennas to allow HIRF testing to be performed in the conventional line-of-sight direct illumination method as well as the reverb method. 

The reverb chambers use a reflective paddle to ‘stir’ the RF to ensure that there are no nulls and that the field strength remains uniform throughout the chamber. The paddle can rotate either continuously (stirred) or in a stepped fashion (tuned), the speed or coarseness of which can be adjusted to suit your requirement.

Mode Tuned Testing

The stirrer is operated in step/stop/step/stop type of operation during Mode Tuned testing. The benefits of mode tuned testing are:

• Useful for slow cycling equipment.
• Field continuous during long dwell times.

Mode Stirred Testing

The stirrer is continuously rotated during Mode Stirred testing. The benefits of mode stirred testing are:

• Much quicker than mode tuned method.
• Dwell time very short. 

With the increased use of composite materials in aircraft fuselages, sensitive electronic equipment is provided less RF shielding from the high field strengths generated by, for example, airfield RADAR. This can result in unexpected exposure to several thousand volts per meter of RF energy which has the potential to cause equipment failure. HIRF testing replicates the pulse modulations and energy levels that high power RADARs generate to ensure that aircraft equipment is sufficiently EM – hardened to withstand them.

The latest revision of RTCA-DO-160 (G) states that all 6 faces of a system must be subjected to radiated susceptibility testing. Due to the uniform nature of the field generated in the reverb chamber, this can be achieved with only one test run, as opposed to six when using the conventional semi-anechoic chamber method, resulting in a significant time and cost saving.  

The HIRF equipment can also be programmed to conduct MIL-STD 461 and Def-Stan 59-411 radiated susceptibility testing as per the respective alternative methods for reverberation chambers.

All HIRF tests are performed under full computer control, with flexibility to provide virtually any frequency step size, pulse duty cycle, or modulation type. 

Benefits of using Reverb method of HIRF Testing

Our reverberation chambers have intrinsic properties of isotropy and homogeneity that provide several unique features for testing:

• Randomly polarized, i.e. the phase between all waves is random.
• Spatially uniform, i.e. the energy density in the chamber is uniform everywhere.
• Isotropic, i.e. the energy flow in all directions is the same.
• Field measurement results will be the same regardless of where in the room they are taken.
• Spatial reconfiguration of the EUT will have minimal effect on those measurements.
• EUT measurements made between one or more chambers will be the same.
• A reverb chamber simulates all wave polarizations and incidence angles during a full test.