Rather than presenting calculated, estimated or simulated results and comparing them against contested SAR thermal specifications, all AegisGuard™ Radiation Shield tests were conducted by three independent laboratories who measured actual radiation emissions in decibels (dB) for multiple products, with and without AegisGuard™ Radiation Shields installed. dB is the standard unit of measurement used to determine the absolute ratio, or comparison, of two voltage, power, gain, loss, or frequency signal levels.
In 1998, globally accepted test procedures developed by the American Society of Test and Measurement (ASTM D4935-99) were used, and custom shields were also made for radio modems to test the shielding effectiveness frequencies up to 2.6 GHz, which was higher than any wireless phone available at the time. The same procedures were used to test AegisGuard™ Wired Headset, (Life) Series and XP Radiation Shields at frequencies up to 2.6 GHz. Click here for additional information about these tests.
During the design phase of AegisGuard™ Life Series and XP Radiation Shields, it was understood that ASTM D4935-99 procedures could not be used for testing shielding effectiveness above 2.6 GHz. because they were not designed to do so. A procedure that might have been used was a military test standard (MIL-STD-285), but it was designed for testing large enclosures and its use has declined since 1997.
On June 25, 1956, the United States Department of Defense (DoD) approved the use of attenuation testing measurement standards and procedures designated as MIL-STD-285 for the electromagnetic shielding of building entrances, doors and large electronic equipment access panels. DoD formally discontinued using this standard on October 24, 1997 after the responsibility for developing and maintaining a new standard was given to the IEEE. MIL-STD-285, however, continues to be used by many testing laboratories.
Although the frequency range of the new standard, designated IEEE-STD-299, is suitable for testing AegisGuard™ L Series and XP Radiation Shields, the procedures were not designed for testing products where the minimum dimension of any side of an enclosure is less than 2 meters (78 inches).
Procedures for higher frequencies were developed in-house to measure the shielding effectiveness of AegisGuard™ Life Series and XP Radiation Shields with the same type of test equipment used by electronic product manufacturers, including wireless phones manufacturers and carriers, and the same procedures were used to test AegisGuard™ L Series Radiation Shields. The results using these procedures are also presented in dB, which is the same measurement used by manufacturers and carriers for testing, and the shielding effectiveness exceeds the requirements specified by MIL-STD-285, IEEE 299 and Human RF exposure limits as set forth in FCC OET Bulletin 65. Click here for additional information about these tests.