Reverberation Characteristics of a Large Welded Steel Shielded Enclosure

摘要

For the past several years there has been an increasing interest in thepossibility of testing large items such as aircraft in a reverberation chamber. One concern has been the scaleability of a chamber's operational characteristics. To test a reasonably large aircraft, a chamber would have to have a volume of 50000 cu. m. or greater. NSWCDD was given an opportunity to test an empty cavity with a volume of about 2500 m3. The Hewlett Packard Company made available their empty, 10-m, semi-anechoic chamber during the final stages of construction. Data collection to satisfy a limited, high priority set of objectives was limited to one weekend. Frequency range was 30 MHz to 18 GHz. (Due to tuner effectiveness and signal to noise level obtained with the limited input power available, the effective frequency coverage was 90 MHz to 6 GHz.) Within acceptable measurement uncertainty, the cavity electromagnetic environment was isotropic, randomly polarized and uniform over the frequency interval tested. The cavity quality factor was somewhat lower than expected. Within the limited data set, there were no significant departures from the theoretical scaleability.